Time Extension: How to Request a Time Extension How to Request a Time Extension

By Juan Rodriguez

Construction Expert

Cultura RM/Seb Oliver/Collection Mix: Subjects/Getty Images

Contract time extensionsare based on the ability to demonstrate that delays have

occurred in the construction schedule affecting project completion date. All time

extension should be bases on delays beyond the Contractor’s control, many of them as

part of change orderrequests. Time extension requests are normally specified in

contract’s provision and requesting time extensions should be made following all steps

and documentation under the contract guideline.

Time Extension: The Reasons

Time extension requests are normally claimed due to the following circumstances:

1. Legal issues are affecting the project’s completion or the contractor’s performance

2. Long lead items, requested by owner, have not been received

3. The Owner asks for a delayed start

4. New or Extra Work not included in the original scope or contract

5. Unusual or adverse weather conditions

6. Encountering sub-surface conditions differing from the plans

It is also important to highlight that time extensions will be denied by the following

reasons:

When the delays claim are caused by subcontractors

When there is insufficient or inadequate workforce

Underperforming by the contractor, specifically procuring long lead items

When the project is affected by normal weather delays

Time Extension: The Process

When requesting a time extension certain steps must be followed, otherwise the time

extension might not be approved. Normally, the Contractor should notify the Project

Manager, when any issue might affect the project schedule.

A formal letter must be addressed to the Contract Administrator requesting the time

extension and the reasons why those days should be added to the construction

schedule. The Contract Administrator should then, remit the letter to the Project

Manager for evaluation and approval or rejection. If the time extension is granted, then

the Project Manager must answer by written and a change order will be issued. Some

contracts specify that time extension requests should be done within a specific

time frame, if not; the time extension claim will also be rejected.

Time Extension: Documents

The time extension when properly presented must contain the following supporting

documents:

Indicate specific issue causing delays

List of activities from project schedule being affected by the aforementioned issue

Exact amount of time being requested specifying working days or calendar days

Sketches, photographs, or pictures

Recommendations being given to Contract Administrator

Indicate the actions the contractor has taken to avoid or minimize other delays

Alternative solutions presented to Contract Administrator

Time Extension: Important Notes

Time extension request should also consider the following:

Calendar days are not the same as working days

Insurances and other bonds will need to be re-issued to cover extend periods

Winter days are shorter or less productive than summer days

Be sure that the time extension requested is enough to cover all delays including additional

items that might be affected

Be sure to understand the changes being proposed and the ramifications of those changes

No additional time will be granted for the same item once it has been approved

In the case of a continuing delay only one claim is necessary

Time Extension: Sample Letter

The Contractor,

Contractor Address

Contract Name

Contract Number

Extension of time

I refer to your extension of time claim dated (insert date of the Claim).In accordance

with clause (insert the contract clause) of the General Conditions of Contract, the

Principal grants extension/s of time of:

Number of days requested and reasons for the time extension.

The Contractual Completion Date (as previously extended) was (insert contract

completion date including previous time extension approvals). This extension of

(number of days) days makes (insert new completion date) the Contractual

Completion Date

Signed by an Authorized Person

Common Causes for a Change Order

Construction change orders can affect adversely a construction project. By Rutlo

Most common causes for a change order can vary from one project to another, but still they are

additions that need to be quantified in terms of time and money. Change orders, sometimes are

a headache when the complexity and time frame of the requested job are tight. Change order

management is another different process than regular contract documents, and most common

causes for change orders can lead to legal battles, disputes and arbitration.

Drawings Errors and/or Omissions

The most claimed situation for allowing change orders. Inadequate details,

misrepresentation o simply avoidance to prepare a complete set of detailed drawings can lead

to serious change order requests. Sometimes leaving out details andmisrepresenting the

exact environment in which the construction will be held at, can also lead to change order

claims.

Design Changes

Several outer factors can lead us to start a construction project without a completescope of the

project and start the construction without final drawings. This type of error is also common on

design-buildprojects, where the on-going process of design can induce to work stoppage or

produce economic impact in the project.

Specifications

Sometime the drawing asks for one product but the specs calls for another. This situation is very

common on construction projects where the drawings are assigned to different consultants,

each one of them acting on their own, without any kind of direction from a team leader.

This leaves the contractor with the difficult task of assuming and quoting on one article, but

when the installation is going to be made, the owner, requires another article to be installed,

instead of the one that you have already quoted.

Unforeseen Conditions

How many times do you have to complete a soil boring? Soil problems, in particular, are the

most common problems with unforeseen conditions. Soil studies can induce you to expect

some condition based on specific testing. This could be wrong. Your assumptions on the soil

conditions or any other issue regarding the construction of the project can be different from the

actual conditions that you find on the site. Also, if the drawings specify a certain amount of

work, when, in fact, the amount of materials is almost double, and then a change order must be

issued.

Substitutions

This is normally a contractor’s idea to substitute material, when he cannot get the specified

materials or there is a shortage in supplies. This is kind of different because it can lead to

another issue: a credit will be asked if the material cost is less, or sometimes the contractor will

have to absorb the costs’ difference between materials and/or products. Sometimes, the Owner

also asks for some upgrades during the construction process, in this case you must submit a

change order request claiming the economic and time costs associated with the proposed

modifications.

The 8 Things to Know About Change Orders Understand How Remodeling and Construction Change Orders Can Benefit You

By Lee Wallender

Home Renovations Expert

It's no fun dealing with contracts when doing home remodeling or home construction. Most

homeowners just want the thing done--minimizing the paperwork as much as possible.

One inevitable aspect of contracts: change orders. Find out how change orders work within the

purview of home remodeling and construction.

What are change orders?

You and the contractor draw up an initial contract to do some work, likely things like new

home building, putting on an addition, installing a pool, and so on.

Because it is inevitable that changes may occur during the course of the project, change

orders allow the contract to accommodate these changes.

Who requests the changes orders--contractor or homeowner?

Both parties can and do request change orders. Kia Ricchi, in Avoiding the Con in

Construction, states,

"Since change orders typically increase the project cost, they are the curse of every

homeowner. Most change orders result from:

Errors and omissions in contracted work

Work arising from unknown conditions.

Owner-requested additional work."

What specific examples might spur a change order?

The most common event that initiates a change order is when the homeowner decides to

add an element to the project: more windows, better windows, different flooring, higher

ceiling, better-grade appliances, etc. Every change in the contract, even the smallest

change, must be documented in the form of a change order.

Why not just strike out and add language into the original contract instead

of making a change order?

This is a practice that homeowners are accustomed to when purchasing or selling a

property--tweaking a price, condition, or other single data point.

Change orders for remodeling and construction are different because so many data points

are involved.

What kind of information is found in a change order?

Change orders are documents that contain a significant amount of information that cannot

be conveyed via hand-written notes to the contract. For instance, the change order will

contain the date of the original contract; date of the change order; original cost; value of

change; cost after change; and much more. Most importantly, change orders give specifics

about exactly what will be done with the change. The change order will need to be signed

by both you and the contractor.

Is there a form for the change order?

There is no universally-accepted change order form, but the contractor will have a change

order form of her/his own. It is rarely more than one page long, and at the very least will

contain the information stated above.

How can I avoid change orders?

As Kia Ricchi mentioned, it would be very rare to encounter a change order that results in a

lower contract value. Thus, it is imperative to avoid change orders as much as possible--

even if you are the one initiating the changes. Ms. Ricchi advises homeowners to

"...develop a concise, correct, complete, and clear scope of work so that the building plans,

proposals, and contract provide for all the necessary work."

Critical Path Method Scheduling

Schedule sample. Courtesy of jwalker64

Critical Path Methodscheduling was developed in 1957, to address challenges on complex

projects. Being one of the most usedscheduling techniques in the construction industry,the

Critical Path Method is a useful toolthat can lead you to achieve your project results.

The Critical Path Method schedule shall include all work specified in the Contract Documents,

including all expected activities of subcontractors, vendors, suppliers and all other parties

associated with construction of the project.

A critical path method will provide you with a graphical view of the project, will provide you the

time required to complete an activity and determine the activities that will become critical to

the project if not completed within the specified time.

Understanding a Critical Path Method (CPM)

A critical path method (CPM) is a network of events, each one of them linked to the

following activities. Each activity is represented as a node on the network, and connecting

lines are drawn to represent the time schedule to complete that activity. A critical path

method schedule must be completed using the following steps:

1. Identify the activities

2. Determine the sequence of the activities

3. Connect or create a network of the activities

4. Enter the completion time for every activity listed on step 1

5. Identify the critical path or the longest possible path to complete all activities

6. One important and valuable component is the CPM update progress, allowing to track closely the

performance and time used to complete the activities

Identify the Activities

A complete list of activities needed to complete the project must be made. This list can be

prepared from the work breakdown structure or the project scope and details. This will be the

key to later add sequence and duration in subsequent steps. Activities shall be identified by

a name, stationing, and coding, and have a duration.

Determine the Sequence of the Activities

This is one key factor of a critical path method (CPM). A complete and thorough

understanding of the sequence of the activities are needed to prepare and connect the list

of activities prepared in the previous step.Linking activities must be analyzed and

connected properly to achieve the expected result, failing to do so can lead to mistakes

and miss-representation of the project activities, leading to a false time frame or erroneous

project completion date. If one crew is being used to perform similar activities, these

activities must be linked together.

Creating the Network

When all activities have been defined and interdependence of activities has been analyzed,

it is required to create the network of activities. It is of vital importance that all critical work

sequence has been linked withlogical coordination and planning requirements. TheCPM

format shall be based on calendar daysas their main planning unit. Working days should

be avoided when planning or preparing a critical path method schedule.

Estimate Activity Completion Time

Using previous experience, time estimates can be presented, and shall represent the

necessary time to complete the activity for a single resource unit. It is one of the most

important steps when preparing a CPM, because it will help you determine the time needed

or available to perform an activity.

Identify the Critical Path

The critical path is the longest-duration path through the network.What does this mean?

Activities located on this path cannot be delayed without delaying the project. Because of its

impact on the entire project, critical path analysis is an important aspect of project planning.

The critical path can be identified using these parameters:

ES – Early Start: earliest time to start a predetermined activity, given that prior activities must be completed

first

EF – Early Finish: earliest finish time for the activity

LF - Late Finish: latest time the activity must be completed without delaying the entire project

LS – Late Start: latest start date that the activity must be started without delaying the project

The critical path is the path through the project network in which none of the activities have been delayed,

that is, the path for which ES=LS and EF=LF for all activities in the path. A delay in the critical path

delays the project.

Update CPM Diagram

As the project is being developed, a critical path method can be updated. Analyzing a new

critical path may be possible, when entering all the duration times of activities already

completed. A new path might be found and alternative solutions can be presented to

either accelerate the project or continue working as projected. Sometimes it is also

necessary to incorporate changes and extra works that were not part of the original critical path.

What Is a Gantt Chart? Learn to prepare a Gantt Chart

By Juan Rodriguez

Construction Expert

ngkaki/E+/Getty Images

What is a Gantt Chart?

A Gantt chart is a bar chart used to illustrate a project schedule, including start and finish dates

of activities and a summary of activities of a project. These activities form what is usually called

thework breakdown structureof a specific construction project. Gantt charts serve as an

excellent tool to show updated schedule status using actual complete shadings and vertical line

representing the actual date.

Gantt charts sometimes are prepared showing precedence activities and following activities and

their relationships.

Gantt Chart Advantages

Using a Gantt chart offers the following advantages:

Gantt charts can be used to represent phases and activities of a project so they can be understood by

general audience.

It can be useful to indicate the critical points on the chart with bold or colored outlines of the bars.

An updated Gantt chart helps manage the project and head off schedule problems.

Computer software can simplify constructing and updating a Gantt chart.

Drawbacks of Gantt Charts

Gantt charts can also have some setbacks:

A Gantt charts is not recommended to define the work breakdown structure and the schedule activities at

the same time.

It has some limitations for large projects, or projects having more than 30 activities.

Gantt charts are not useful if they are intended to display information.

Gantt charts do not represent the complexity of a project.

Horizontal bars of Gantt charts misrepresent the actual resource requirements of a project.

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Gantt chart with percent-complete shading may actually miscommunicate the true schedule

performance status.

Gantt Charts: When to Use It

Gantt charts have a variety of uses among construction professionals. Gantt charts must be

used under the following circumstances:

To communicate plan or status of a construction project.

To monitor tasks within a project.

To express the sequence and duration of specific tasks or process from a construction project,

To demonstrate which tasks depend on completion of previous tasks.

Gantt Chart Basic Procedure

The basic procedure must be followed to build a Gantt chart.

1. Identify the steps or activities needed to complete the project.

2. Identify milestones within the project.

3. Identify the expected time required to complete each task.

4. Identify the sequence of tasks and the order of precedence of tasks.

5. Draw a horizontal time axis on the bottom of a page.

6. Select a proper time scale to represent the length of tasks.

7. Prepare a column on the left side of the paper; write down each activity and milestoneof the project in

their corresponding order of occurrence.

8. Activities or milestones that occur at a specific point in time represent them using a diamond under the time

the activity must happen.

9. Activities that occur over a determined period of time draw horizontal bars, or an empty rectangle starting

from the first day the activity will take place and finishing the day the activity ends. Do not fill inside the

rectangle.

10. Each activity or tasks must be listed in the Gantt chart.

11. Fill up the diamond or the rectangle as each activity is being performed.

12. Use a weight or plumb as vertical marker to illustrate that actual time and progress of the project.

Gantt Chart Considerations

Gantt charts are also modified with additional columns showing details such as the amount of

time estimated to perform each task, how many resources are needed to complete each activity

and/or the person responsible to execute the activity. Specific meetings or reviewing processes

are not recommended to be listed on a Gantt chart because they might occur over a long period

of time. Gantt chart will transmit a clear idea to construction professionals about what must be

done to complete a specific task and can promote a healthy scheduling process.

Contract Documents Construction Contract Must Have Items

By Juan Rodriguez

Construction Expert

The contract documents are one of the most important pieces that will guarantee of a successful

project. This list contains the most common documents that must form part of every

construction contract.

In addition to this list, there are other numerous contract support documents that can be used in

combination with the standards documents. For example:

Instruction Forms

Time Extension Claim

Request for Information

Preliminary Building Agreement

Progress Payment Certificate

Practical Completion Notice

Defects Document

Contract Information Statement

Contract Document.

1. Agreement

The agreement to be used by the contracting officer (owner) and the contractor.The most

essential part of the contract documents.

2. General Conditions

This contract document will define the obligations and rights on how to execute the project.

3. Special Conditions

This is usually an extension of the contract and to the general conditions. This part must specify

specific conditions and clauses to each particular project or job.

4. Bill of Quantities

This is formed by the list of diverse trades, and materials included that form part of the

construction. Sometimes this document is not required by the contracting officer.

5. Drawings

All set of drawings that form part of the job to be performed. These drawings are usually

the latest drawings and must be received by the contractor prior to the date of commencement.

It must include all drawings from consultants, and will constitute the entire project being

contracted.

6. Specifications

The technical requirement to complete, execute and/or perform every little task or material being

incorporated in the construction projects. It will add intelligence to the construction

drawings;specify common standards, deviations accepted, materials accepted and the

required testingfor all materials. Usually, specifications are composed by referencing

construction standards and codes.

Schedule sample. Courtesy of jwalker64

7. Schedules

The construction schedule is an important piece of the document. In this part, the contracting

office will know how and when the project will be completed. Sometimes,construction

contracts will require updated schedules throughout the construction progress, and might form

part of the monthly, or agreed term, application for payments.

8. Pricing Schedules

Breakdown of all items being incorporated in the construction project. This is usually the base of

the application for payment. It can be detailed per item or in a lump sum form, not specifying

individual items.

Performance bond. J Rodriguez

9. Insurances

This part will be an essential part to the contracting officer, since, it will provide the guarantee to

the owner that the contractor has the means and the economic backup to perform the

construction contract. It will include specific types of coverage’s, required bonding, and

all insuranceprotections to the owner, the contractor and third parties.

Work Breakdown Structure (WBS)

By F. John Reh

Management & Leadership Expert

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Definition:

A Work Breakdown Structure (WBS) is the organized listing of all the tasks in a project. All the

tasks needed to complete a project are listed. The major tasks are listed and then the sub-tasks

of each task are listed below them. Then the sub-tasks of each sub-task are listed below them.

This continues until all the tasks have been listed. This list is the work breakdown sructure.

Also Known As: Project Task List

Examples: After building the work breakdown structure, the project manager assigned

dependencies to each task in order to begin setting the project plan.

Selecting the Best Architect How to Choose the Best Architect

By Juan Rodriguez

Construction Expert

Selecting the Best Architect

The architect plays an important and decisive role in your construction project. The architect

must be hired if you are considering to build a new home or completing a renovation. Hiring the

architect is a process that will help you come up with new ideas and planning spaces, and also

will help you with every step in the construction process. Starting from the planning process and

ending with all the required documentation, the architect is a valuable piece and key process

within the construction industry.

Architects

Green Architecture

Architecture Firm

Design Build Architects

Construction

The selected architect will be able to meet your needs, clarify some doubts and get your

project in compliance with several construction codes and laws. Also the architect will help

you presenting the first realestimate or budget for your new construction project. Your architect,

if decided by agreement, will oversee construction activities and will ensure that your project is

being built in accordance with the construction drawings and specifications.

The Architect in the Construction Process

The architect will design and plan the use of space within your project. He will be acting on your

behalf in every aspect and will be your eyes during the construction process. The architect will

be selecting the materials used in the construction based in your selection and the performance

of the selected materials, using a unique combination of expertise and knowledge. Furthermore,

he will be negotiating with the contractors the time frame to start and finish construction and

help you with all the required permits and compliance with local, state and federal ordinances.

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The following steps will help you in the selection of the architect:

1. Ask for recommendations from friends, family or business associates.

2. Set up an interview with the architect. Prepare a list of your main concerns and discuss it with

their representative. Remember, not all questions will be answered but in general terms, the

architect can guide you and inform you.

3. Research on his background and expertise area. There are several types of architects, and

not all of them work with the same kind of projects.

4. Ask specific questions about their services and their scope of work.

5. Compare several architects, with the information that you have gathered.

6. When selected, please be aware that the construction process is a process that takes time

and not is a fast paced from the beginning.

Remember the benefits of hiring the architect are numerous and that the relationship between

the Architect and you, needs to feel comfortable, up front and above all honest, they will be your

closest confident while bringing your dream to life.

Whatever stage you are with your building project, at planning, designing, submitting the

development application, or you are actually starting the construction, the architect will help the

process run smoothly and the hard work out of it for you.

How the Eichleay Formula Can Be Used to Recover Overhead Costs Using thie Formula Might Help You on Claiming Home Office Overhead

By Juan Rodriguez

Construction Expert

The Eichleay Formula is one of the most used calculations when computing home office

extended overhead damages in construction delay claims. Construction delay claims regarding

extended overhead are among the most complicated claims and almost always require the

services of an expert to both determine damages and how those costs can be recovered. Home

office overhead costs include salaries of management staff, clerical staff, utilities, supplies,

dues, training and insurances, to name a few.

Since it is so difficult to separate the costs associated with a particular project, then these costs

need to be properly identify by assigning a percentage of the total amount of these costs.

Why Does the Eichleay Formula Is Being Used

Normally, Eichleay formula is used when the project has been completed and costs are

available and accountable. The Eichleay formula was established following a decision of the

Armed Services Board of Contract Appeals in Eichleay Corporation, ASBCA No. 5183, 60-2

BCA 2688 (1960), used to calculate home office overhead. In 1984, the Federal Circuit held that

the Eichleay formula was the most appropriate method of allocating home office overhead.

Steps to Calculate Extended Overhead Through the Use of the Formula

Using the Eichleay formula requires three steps for the calculation process:

For these calculations you must multiply the total home office overhead cost by the ration

between project billing and general company billings.

Is obtained form the rate between allocable overhead (step 1) between the days of contract

performance including delay days.

Getting to this point is easy. Just multiply the total amount obtained from step #2 by the delay

days. That total will be the total claim amount that you will be asking for.

1. Find the Contract Allocable Overhead - To find the contract allocable overhead, start by multiplying the

total overhead cost identify during the total contract period by the proportion of billings from the delayed

contract to total billings of the firm during the contract period.

2. Daily Contract Overhead Rate - To calculate the daily contract overhead ratio, divide contract overhead

by the contract performance time (by days)

3. Home Office Overhead - To get the final amount, multiply the daily overhead rate by the amount of delay

days caused by the project owner.

How the Project Owner Can Challenge the Use of the Eichleay Formula

There are certain instances that a project owner can challenge the contractor when the formula

is being used. Here are some of the most common arguments a contractor needs to be ready to

be challenged:

The formula is considered an estimate and its accuracy can be questioned.

Contractors can shift their overhead costs to other projects concurrent with the contract being challenged.

The contractor must prove that delays decreased the stream of direct costs.

The contractor must show that it was unable from taking on other work

You must provide further evidence that the actual office overhead costs are real, by usingaudited financial

statements, information that many small contractors can’t afford.

Some objects included in home office overhead, as entertainment and ads, can be questioned.

Sometimes the contractor must prove that the bonding capacity has been limited.

Resources such as equipment and labor were only available and are still in the 'limbo' just because the

project has been delayed.

Some of the contracts might have set a fixed fee for the contract profit.

Some courts may not recognize Eichleay formula for calculating extended overhead.

When project has been substantially completed, it is hard to justify claims from office extended overhead.

The reason for this is that it can be argued that expenses have already been paid to the contractor.

Common Office Overhead Costs

Some of the costs that can be included during this claim process are classified as indirect or

direct costs. It is important to understand and how to recognize these costs to accurately include

them in the claim. Here is a list of the most incurred office overhead costs:

Salaries and fringe benefits of management, clerks and security personnel. Be sure to include accountants,

executives, and in some instances outsourced employees.

All rented equipment such as copiers, phones, fax and other equipment.

Internet, alarm systems, and any other monthly or recurrent cost.

Insurances and bonds.

Marketing, advertising and travel costs.

Legal fees and human resources staff.

Temporary and permanent office structures.

Project management and/or engineering team costs

Leases and land acquisition fees/contracts

Job specific rentals: equipment, labor, trailers, security, utilities and vehicles.

Impact Analysis: Time Impact Analysis Time Impact Analysis

By Juan Rodriguez

Construction Expert

Mike Clarke/E+/Getty Images

Impact Analysis: Time Impact Analysis

A Time Impact Analysis is a method used to determine extent of impact from potentialdelay in

construction process. Time Impact Analysis could be one of the preferred methods to promote

negotiation and later agreements on delay claims. Time impact analysis is done using existing

schedules, analyzed with all related input entered into the schedule to demonstrate the reason

or possible effects on schedule.

Time Impact Analysis is usually performed by a project scheduler and can be used on the vast

majority of construction projects.This schedule analysis method involves the insertion or

addition of activities indicating delays or changes into an updated schedule representing

progress up to the point when a delay event occurred to determine the impact of those delay

activities.

Time Impact Analysis Expectations

A Time impact analysis will be applied to forecast the construction process and analyze what is

going on and what the outcome will be. It requires a CPM schedulethat is able to show the pure

CPM calculation differences between a schedule that does not include a delay and one that

does include an activity modeling a delay. A time impact analysis is required to calculate with

a standard method the results to the actual project delay.

The analysis is not the project reality simulation, it is intended to understand the time impact

caused by a single event or series of events, and how they will impact the project schedule.

It is a great tool on projects that are currently ongoing and will present a real-time idea of how

the contract adjustment is required. The final result of the time impact analysis must be

presented shortly after completion to the contractor; otherwise, he might present an

additional time extension claim of constructive acceleration. It is the best technique for

determining the amount of Extension of Time that the Contractor should have been

granted at the time that an excusable risk occurred.

Time Impact Analysis Uses

Time impact analyses are used on these occasions:

1. When the contractor has not been able to provide remediation instructions and it is not able to redeploy his

workforce.

2. . Time impact analysis is an excellent tool to measure actual delays on events that are undergoing

construction activities.

3. The analysis could be used when delays are already being expected due to external or internal

circumstances.

4. Time impact analyses are used to model delays on short or simple construction activities. If delays are

longer than usual additional methods and tools must be used in conjunction with the TIA.

Time Impact Analysis: When to Avoid It

Time impact analysis should not be used or will not present the best results when:

1. It must be avoided if your actual project schedules have not been updated. TIA will not present a real

outcome when data input on the analysis has not been updated with real data from the construction

activities.

2. Work plans based upon resource considerations are more easily adjusted without detriment to the project

completion or planned expenses than those based upon physical constraints.

3. Time impact analysis should be avoided when mitigation work has already been started. If the

constructions schedule has been altered, the less effective the modeling of the delay will be.

Time Impact Analysis Procedure

A time impact analysis requires the following steps:

1. The delay should be described as simply as possible with the fewest number of activities reflecting the

project delay.

2. Select the schedule to impact. The schedule should be latest updated schedule of the project.

3. Add the impact activities and make the necessary adjustments to project schedule.

4. Recompute the CPM and note a change in the project completion date.

5. Determine the amount of project delay.

6. Determine the actual dates of the delay using the original schedule

Time Impact Analysis Checklist

When performing a time impact analysis be sure to:

1. Study and understand the scope of the directed change or analyze the extent of the delay being found.

2. It is important to analyze all documents, field directions, contract clauses, drawings, orders, specifications

and conditions that could exert any kind of influence to the expected delay.

3. Identify and describe the condition encountered before performing the time impact analysis.

4. Identify all related construction activities that are or could be affected under the expected delay.

5. After a complete analysis of the construction schedule, determine all related dates, start, duration and

finish, for all affected activities.

6. Prepare a complete set of documents that define when the delay started, what actions took place at that

moment, and demonstrate the effects of the delay on the actual updated schedule and how the remaining

activities should be altered, if required, to complete the project on time.

7. The time impact analysis could present you with the overall schedule result incorporating drawings,

contract requirements, and any type of document that support final conclusions. It is important to highlight

extraordinary measures required to bring the project back on schedule.

8. Be certain that actual delays are result of the change directive or delay, not from a non-excusable cause.

Bid Tips - Government Projects Construction Bid Tips

By Juan Rodriguez

Construction Expert

Bid Tips on Government Projects

These bid tips will increase your opportunity to be contracted. If your bid proposal doesn’t have

the correct ingredients or is poorly targeted, you will be eliminated from competition, without

being able to bid fairly with other contractors. Avoid these bid errors when making your

proposals for government projects.

1. Bid Language. Remember, being simple will allow you to get benefits, contract and bid doors

will be open for you.

Keep it simple, avoid confusing language, and be straight to the point, present facts not ideas.

The wording that you use will be the key for someone to keep reading your bid or to put it aside.

Don’t use long sentences and paragraphs, it’s distracting and probably the reader will lose all

connection with your idea.

2. Don’t Risk Current Projects. Sometimes you will bid on something that, maybe you can’t

complete or don't have the available personnel to do it. Make sure and convince your reader

using past projects or past experiences that you have the necessary skills to do it. You

will then re-focus on gather resources to the new project while your other projects will be left

unattended from you or your staff.

3. Credit Cards. Actually many government agencies makes transactions using credit cards,

and sometimes is a requirement on the bid proposal, for you to present evidence that you can

be paid using plastic.

4. Using Incorrect Bid Units. The most common mistake. Bid what they ask you in the units

they are requiring to do so.

Sometimes they require you to submit a bid price for linear feet, instead your past experience

has allowed you to quote based on linear meter. Don’t use meters if they ask for feet. It may

appear like a mistake, but it can cost you, and present the image that you are not careful.

5. Clean bids. Imagine, if your bid is a mess, what can they expect from you in a project?

Check every piece of paper not only in the front but also in the back, your papers should be neat

and clean, and remember to number the pages and bind everything. Remember every piece of

paper is justified and has one specific purpose.

6. Agencies need. Don't discard any agency just because of their name. You will get surprised

to know all the requirements needed from some agencies, it might sound strange but don’t close

the doors.

7. Bid your skill. Instead of presenting vague or general ideas of your business, nail the

proposal by answering specific requirement solicitations. Present specific ideas on how to solve

the problem, what would you do and how would you do it.

8. Bid Time. Time is essential. Every bid proposal has a deadline that you must meet. Failing

to do so will let you out of business immediately. Don’t wait until the last moment to send your

bid proposal, sometimes the mail get stuck with lots of letters, specially during the holiday

season.

9. Out-Bid Your Competitors. How you would be highlighted from other competitors? What

can you complete or do different than the others? What benefits are we going to receive from

you?

Sometimes winning a bid government is not an easy job, but with these guides you will be so

close to get one, that it is worth a try.

Bids: Common Bidding Errors and Recommendations Bidding errors and how to avoid them

By Juan Rodriguez

Construction Expert

Here are some common errors found when bidding construction projects. There are other

items that you must also consider on a bid like: overhead percentage, mobilization, warranties,

experience, fill-in every line on the bid form, contingencies and allowances. Remember the key

to a successful bid is a mix of experience, performance and remember to follow the

instruction to bidders.

1. Bid Error: Arithmetic

Common bidding errors on calculation and using the wrong scale will lead you to the most

common error when placing a bid. Recommendation: Use bidding software or an electronic

calculator with a recording tape. Remember always to double-check quantities and pricing.

2. Bid Error:Improperly Pricing

Verify the quantities and supplies needed; check if the bid requires a lump sum or a unit

price.Recommendation:Pay special attention when reading the instruction to bidders.

3. Bid Error: Incorrect Allowances

Allowing too much or too little amount to perform a job might send a signal to the owner or the

manager that something on your bid is wrong. Recommendation: Prepare a detailed proposal

for the allowance and prepare a complete take-off for this job. Present the number as requested

in the proposal, fixed price, unit price, lump sum, or per instructed.

4. Bid Error: Incorrect Units

Check theschedule of valuesto verify if they are requiring the bid on a lineal feet, yards or

meter unit.Recommendation:Double Check and prepare a separate list with the requested

units

5. Bid Error: Labor Rates

Labor rates vary widely from jurisdiction to jurisdiction. Some projects require you to comply

with Davis-Bacon Act, local union salary rates, among others.Recommendations: Consult local

business, laws and other reliable resources to get the correct rates and how to incorporate them

to your bid. Special attention must be given to overtime rates.

6. Bid Error: Unfamiliarity With Project Site

Huge mistake! Some contractors present bid by merely completing a take-off from construction

drawings. Recommendation: Complete a Due Diligence assessment and verify that field

conditions are represented on construction drawings.

7. Bid Error: Transportation Costs

That huge piece of steel or that unique material must be transported by train, plane, of

overnight. Request a quotation for the delivery of the material and plan its delivery. Broker costs

or special taxes might add up to unexpected quantities. Recommendation: Prepare a logistic

plan of when and how the material will be transported. Remember to provide specific or realistic

date and stick to that quotation as long as you can.

8. Bid Error: Regulations

Every jurisdiction has a local or state code that must be followed. Sometimes these codes

request for special equipment or additional pieces that were not part of the initial

bid.Recommendation: Hire or consult a local expert that will help you on the assessment of the

construction codes

9. Bid Error: Quality

Sometimes contractors tend to work in certain ways, but specific regulations might require to

bring specialized contractors, even licensed contractors, to perform a job. When bidding be

sure that every requirement is being met, and that the proposed workmanship is

appropriate. Recommendation: Look for high specialized items under the contract and request

a quotation from specialized contractors, this will guarantee that you will be in compliance with

all requested labor quality.

10. Bid Error: Minor Items

Minor items tend to present major costs. Sometimes a bid proposal will not require presenting a

bid number for waste disposal, or even scaffolding; but be aware that adding these little costs

can lead to a significant portion of your bid total. Recommendation: Analyze and list all

necessary equipment to perform a job, no matter how small that equipment can be or how short

its usage will be.

11. Bid Error: Overlapping Items Different subcontractor's can be bidding on the same item if their scope is not precise.Be sure to verify

the extent of the quotation from your subcontractor's and discuss its proposal. Recommendation:

Prepare a scope of work and distribute it to your subcontractor's. On a construction drawing mark the

limits of each contractor and discuss with them what items they are including on their bidand what

items they are leaving unattended.

12. Bid Error: Assumption Many bidders tend to use a rule of thumb quoting price for some items. Regularly, you tend to

analyze your job on a per square price, as you used to, but variance in construction costs or specialties in

the construction project might increase those 'ballpark' estimates.Recommendation:Use specific area

details and a complete analysis of your construction project.

13. Bid Error: Alternate Bid Regularly bid request asks foran alternate bid number. Leaving this area without any information will

disqualify you from the competition.Recommendation:Follow the strict guidelines and the instruction to

bidders as closely as you can.

14. Bid Error: Signing Bid answers and quotations are always prepared against the clock, but you must never forget to sign

the bid bond or the bid proposal. Recommendation: Establish a checklist procedure before sending your

bid proposal.

15. Bid Error: Time-Limit Bid proposal always requires to be delivered on a specific time frame. If you plan to answer a bid

proposal organize your subs and your employees to finish the proposals with at least 24 hours

before the specific deadline. Recommendation: Finishing before the due date will leave you enough

time to review the proposal and to get sure that every instruction or detail is covered.

Lump Sum: What Is A Lump Sum? Lump Sum Construction Contracts

By Juan Rodriguez

Construction Expert

A lump sum contract is normally used in theconstruction industry toreduce design and

contract administration costs. It is called a Lump Sum because the contractor is required

to submit a total and global price instead of bidding on individual items. A lump sum contract

is the most recognized agreement form on simple and small projects, for example, projects

with a well-defined scope orconstruction projects where the risk of different site conditions is

minimal.

Lump Sum Contract Basics

A lump sum contract or a stipulated sum contract will require that the supplier agree to provide

specified services for a stipulated or fixed price.

In a lump sum contract, the owner has essentially assigned all the risk to the contractor, who in

turn can be expected to ask for a higher markup in order to take care of unforeseen

contingencies. A supplierbeing contracted under a lump sum agreement will be responsible for

the proper job execution and will provide its own means and methods to complete the work.

This type of contract usually is developed by estimating labor costs, material costs, and adding

a specific amount that will covercontractor’s overhead and profit margin.

The amount of overhead calculated under a lump sum contract will vary from builder to builder,

but it will be based on their risk assessment study and labor expertise. However, estimating a

very large overhead cost can lead the contractor to presenthigher construction costs to the

project owner. The expertise of the contractor will determine how their estimated profit will

actually be; furthermore, a poor executed and long-delayed job will raise your construction costs

and eventually diminish the contractor's profit.

Lump Sum: When to Use It

A lump sum contract is a great contract agreement to be used if the requested work is well-

defined and construction drawings are completed. The lump sum agreement will reduce owner

risk, and the contractor has greater control over profit expectations. It is also a preferred choice

when stable soil conditions, complete pre-construction studies and assessments are completed

and the contractor has analyzed those documents. The stipulated sum contract might contain,

when agreed-upon parties, certain unit prices for items with indefinite quantities and allowance

to cover any unexpected condition. The time to award this type of contract is also longer;

however, it will minimize change orders during construction.

Lump Sum Contract Advantages

A lump sum contract offers the following advantages:

Low risk to owner.

'Fixed' construction cost.

Minimize change orders.

Owner supervision is reduced when compared to Time and Material Contract.

Contractor will try to complete the project faster.

Accepted widely as a contracting method.

Bidding analysis and selection process is relatively easily.

Contractor will maximize its production and performance.

Lump Sum Contract Disadvantages

This type of contracting has also limitations:

It presents higher risk to contractor.

Changes are difficult to quantify.

The Owner might reject change order requests.

The project needs to be designed completely before the commencement of activities.

The construction progress could take longer than other contracting alternatives.

Contractor will select its own means and methods.

Higher contract prices that could cover unforeseen conditions.

Lump Sum Critical Items

Lump sum contracts are a great tool for smaller jobs and quite simple projects. However, lump

sum contracts could eventually produce large dispute and claims that will arise fromcontract

documents. The most common arguing factors are:

1. Unbalanced Bids

2. Some projects might require to produce an application for payment using unit quantities and unit prices.

Many contractors will produce an unbalanced bid by rising unit prices on items to be completed early in

the project, such as mobilization, insurances andgeneral conditions, and lowering unit prices on items

needed in later stages.

3. Change Orders

If the owner produces or receives a change order proposal from the contractor, the price quotation could be

possibly disputed. The Owner might appeal that the requested change was already covered under contract

provisions. It is important to prepare specific contract clauses specifying how change orders are going to be

managed and to what extent the contractor could claim delay damages.

4. Design Changes

5. A contractor may suggest design changes based on their experience. Contract provisions should be

clear on how those changes will be addressed and how those costs will be divided or who will be

responsible for the economic impact of the proposed changes.

6. Early Completion

7. Lump sum contracts might include an early completion compensation for the contractor. Early

completion might produce higher savings for the project owner; however, those clauses might be explicit in

the construction contract.

Hold Harmless Agreement Three Types of Hold Harmless Agreement

By Juan Rodriguez

Construction Expert

A hold harmless agreementis a contract clause typically found in construction contracts. The Hold

Harmless agreement is commonly provided by the subcontractor to the contractor, builder, or others

related professionals insuring against all work being executed by the subcontractor.The provisions

under a Hold Harmless agreement will minimize the risk of being part of a litigationor allow you to

pursue a claim for indemnity if a subcontractor or any of his employees sustain an injury. A hold harmless agreement clause in a contract document should have a specific language to protect the

contractor or the intended parties.

The agreement must include provisions to neglect any kind of claims, damages, losses, expenses or any

other cause of action to the contractor, if any type of problem or disputearises in the construction project.

The hold harmless agreement protection will vary depending on the jurisdiction that the contract is

being executed. In some cases, the hold harmless agreement will protect the contractor from claims

brought by corporations or companies not forming part to the agreement.

Three Basic Types of Hold Harmless Agreements

There are three basic types of Hold Harmless Agreements in the construction industry:Broad Form,

Limited Form and Intermediate Form. 1. Broad Form

2. The subcontractor being insured, assumes all related liability for accidents, its own negligence, general contractor

negligence and the combined negligence between contractor and subcontractor. This is not the recommended form of

agreement due to its broad responsibility terms, and many jurisdictions prohibit this form of hold harmless

agreement. In some cases to validate this type of agreement, the subcontractor must finance its own liability with an

additional insurance policy.

1. Intermediate Form

2. Under this form of agreements the sub contractor assumes all liability for accidents and negligence. The

subcontractor is responsible for his related actions and will not be held accountable for the general contractor's

accidents or negligence. This is one of the most common used types of hold harmless agreement. It is not dependent

on whether it was subcontractor's fault or not, it only depends on whom was executing the accident or who was acting

in a negligent way. In the case that both parties were negligent, thesubcontractor will be held responsible for his

actions and will be liable for his actions and omissions.

3. Limited-Form

4. In a hold harmless limited-form agreement, the subcontractor will be held accountableonly for the accident or

negligence but on a limited form. The subcontractor will assume liability only to the proportional part of what was

his responsibility. This type of agreement will limit the liability of the subcontractor only to his responsibility, and

will include other, under their respective hold harmless agreements for their corresponding part of the accident or

negligence.

Contract Documents Construction Contract Must Have Items

By Juan Rodriguez

Construction Expert

The contract documents are one of the most important pieces that will guarantee of a successful

project. This list contains the most common documents that must form part of every

construction contract.

In addition to this list, there are other numerous contract support documents that can be used in

combination with the standards documents. For example:

Instruction Forms

Time Extension Claim

Request for Information

Preliminary Building Agreement

Progress Payment Certificate

Practical Completion Notice

Defects Document

Contract Information Statement

1. Agreement

The agreement to be used by the contracting officer (owner) and thecontractor.The most

essential part of the contract documents.

2. General Conditions

This contract document will define the obligations and rights on how to execute the project.

3. Special Conditions

This is usually an extension of the contract and to the general conditions. This part must specify

specific conditions and clauses to each particular project or job.

4. Bill of Quantities

This is formed by the list of diverse trades, and materials included that form part of the

construction. Sometimes this document is not required by the contracting officer.

5. Drawings

All set of drawings that form part of the job to be performed. These drawings are usually

the latest drawings and must be received by the contractor prior to the date of commencement.

It must include all drawings from consultants, and will constitute the entire project being

contracted.

6. Specifications

The technical requirement to complete, execute and/or perform every little task or material being

incorporated in the construction projects. It will add intelligence to the construction

drawings;specify common standards, deviations accepted, materials accepted and the

required testingfor all materials. Usually, specifications are composed by referencing

construction standards and codes.

7. Schedules

The construction schedule is an important piece of the document. In this part, the contracting

office will know how and when the project will be completed. Sometimes,construction

contracts will require updated schedules throughout the construction progress, and might form

part of the monthly, or agreed term, application for payments.

8. Pricing Schedules

Breakdown of all items being incorporated in the construction project. This is usually the base of

the application for payment. It can be detailed per item or in a lump sum form, not specifying

individual items.

9. Insurances

This part will be an essential part to the contracting officer, since, it will provide the guarantee to

the owner that the contractor has the means and the economic backup to perform the

construction contract. It will include specific types of coverage’s, required bonding, and

all insuranceprotections to the owner, the contractor and third parties.

Time and Material: Time and Materials Contract Things to know when using a Time and Materials Contract

By Juan Rodriguez

Construction Expert

Joe Raedle/Getty Images News

Time and materials contractsare used when both parties agree to pay predetermined unit rates.

Time and materials contracts are used when it has been impossible presenting an accurate

estimate or where the schedule cannot be defined. This type of contract presents the highest

risk for the owner and the most secure way for a contractor. Time and materials contracts are

the least desirable contract type for the federal government.

Time and Materials Contracts Items

When using time and materials contracts, the following items could be negotiated:

1. Labor Rate- Specifying a fixed rate for all labor including administrative personnel. If you are using T&M on

large projects, be sure to offer discounted labor rates to reduce total project cost.

2. Material Mark-Up- T&M contracts usually add between a 15 and 35 percent onto material prices.

3. Not-to-Exceed- The Time and Material not to exceed, is a contract in which the contractor can bill the work

being performed but there is a cap that could be used as the maximum amount being charged by the

contractor. This type of variation can be used to increasecontractor’s efficiency and it assumes the

excessive costs. It also provides the owner with a cap that will guarantee that contractor will not exceed

from that cap.

4. Maximum Labor Hours- In addition to the not-to-exceed condition, time and material contracts, a maximum

number of labor hours could be set. When the contractors exceed a specified amount, those additional

hours shall not be billed to the other party. This avoids the “less efficiency = more money” issue of time and

materials contracts.

Time and Material Contracting

Some federal agencies use time and material contract, although not popular among

governmental agencies. Some of the agencies that use T&M Contracts are:

Defense Information Systems Agency (DISA)

Federal Transit Administration (FTA)

U.S. Department of Defense (DOD)

Time and material contracts in the federal government can be used once the contracting officer

determines that it is the most suitable contract that can be issued, and when the contract

includes a not to exceed conditions. The Federal Acquisition Regulations (FAR) explain that this

demonstration may be made by establishing that it is not possible at the time of placing the

contract to estimate accurately the extent or duration of the work or to anticipate costs with any

reasonable degree of confidence (FAR 16.601(c)). When using T&M, the government must also

perform surveillance of contractor performance.

Time and Material Contracts Drawbacks

Time and material contracts has also some disadvantages such as:

Profit Limits- Some savvy customers will try to establish not to exceed conditions, will try to reduce mark-up

on materials and even negotiate reduced billable per hour rates.

Ignored Market Prices- Sometimes companies will set lower prices, based on their internal cost structure,

than actual market rates or even vice-versa.

Reduced Business- Customers are not used to work on time and material contract, so finding new business

opportunities, could be really challenging. Customers will likely preferred fixed price contracts.

Billing- Time and materials contracts should be structured in such way that the company will be able to bill

sufficient amount of money to cover fixed costs. When the billing hours are reduced, fixed costs must also

be reduced at the same rate as the billable hours.

Application For Payment Form Application for payment basic form

By Juan Rodriguez

Construction Expert

An application for payment is a construction document that identifies and presents a method on

how a contractor will be paid. The application for payment contains the services or items that

are being incorporated or jobs being executed under a contract agreement. It is usually

presented as a list with the unit price of each item and the quantities of product/material being

furnished.

Application for Payment Importance:

An application for payment provides both the owner and the contractor, with a method of

controlling what items or materials have been provided by the contractor. It is a great toolto

expedite payment and minimize error possibility.

1. Application for Payment General Form There is some Application for payment standards form widely used:

· AIA Forms - G702 Application and Certificate for Payment,

· ConsensusDOCS 291: Application for Payment (GMP)-Facilitates the calculation and

documentation of progress payments where the basis of payment is a guaranteed maximum

price.

· ConsensusDOCS 292: Application for Payment (Lump Sum)-Facilitates the calculation and

documentation of progress payments where the contract price is a lump sum.

· ConsensusDOCS 293: Schedule of Values-Provides a breakdown of the cost of elements of

the work and should be used with the ConsensusDOCS application for payment forms

(ConsensusDOCS 291 and ConsensusDOCS 292).

2. Application for Payment: Schedule of Values The Schedule of Value, is the sheet were items are listed along with their unit prices, quantities

and summary of what has been paid and what is being certified for payment. It provides a

general overview of the project status.

3. Application for Payment: Schedule #2

The Schedule #2 provide a comprehensive list of subcontractors that took part during the

respective period, performing works under the specified contract. It is require to justify the

amounts being certified under the

4. Application for Payment: Schedule 3 The Schedule #3 under the application for payment is a document that releaes and waivers of

claims and stop notices from all Subcontractors furnishing labor, services, or materials covered

by the certificate for payment.

What is Builder’s Risk Insurance? Information of coverage and exclusion of the Builder's Risk Insurance.

By Juan Rodriguez

Construction Expert

Justin Sullivan/Getty Images News

What is Builder’s RiskInsurance? Builder’s Risk Insurance, people also refer to it asCourse of Construction, is some kind of property

insurance. It's a form of insurance, which covers a building where the building is presently being

constructed. It can cover just the structure, or also the materials on site waiting to be installed or

transported to the job site.

The builder's risk insurance policy will pay for damages up to the coverage limit.

The limit must accurately reflect the total completed value of the structure (all materials and labor costs,

but not including land value). The construction budget is the best source for determining the appropriate

limit of insurance.

Builder’s Risk insurance policies can often be written in terms of three-months, six-months, or 12-

months. If the project is not completed by the end of the initial policy term, it can often be extended, but

usually only one time.

What Does a Builder's Risk Covers?

The builders risk policy will provide coverage for damage done to the insured structure from a wide

variety of events. Damage from the following events will be covered by most policies:

Fire

Wind (may be limited in coastal areas)

Theft

Lightning

Hail

Explosion

Vandalism

Vehicles/Aircraft

You should read your course of builder's risk insurance policy to be familiar with its limitations and

exclusions. Limited coverage is provided for collapse. Standardexclusions include:

Earthquake

Employee theft

Water damage

Weather damage to property in the open

War

Government action

Contract penalty

Voluntary parting

Mechanical breakdown

An important exclusion which should be read in its entirety excludes coverage for damage resulting

from faulty: design, planning, workmanship and materials. Earthquake and flood coverage may be

purchased in some areas.

Extensions of coverage may be provided for certain situations. The coverage for these may be limited.

Common builder's risk insurancecoverage extensions include:

Property in transit A coverage extension to protect your property from loss while being transported to the jobsite.

Scaffolding Coverage is extended to apply to scaffolding, construction forms and temporary structures, but only while they are at

a location you have reported.

Property in temporary storage Property that will be used or installed in the secured location and pertaining to the insured company.

Fire department service charge When the fire department is called to save or protect covered property from a covered cause of loss.

Debris removal The builder's risk insurance policy will pay your expenses to remove debris of covered property. This debris must

result from a loss that is covered under this form.

Sewer and Drain Backup Water damage from the back-up of sewers and drains is usually covered.

Valuable papers (site plans, blueprints, etc)

Important Notes

Some additional information that you should know: The insurance will not cover the property of others.

Sub-contractors are required to have their own insurance.

There is no coverage for tools or equipment.

No coverage for liability.

It does not cover accidents in the job site.

Usually coverage ends when the building is completed, or occupied.

The premium for the annual policy is fully earned.

For specific terms, coverage and exclusions, the original builder's risk insurance policy will

determine the applicable coverage.

Performance Bonds Performance Bonds Basics

By Juan Rodriguez

Construction Expert

Lawrence Sawyer/E+/Getty Images

Performance Bonds guarantee for the satisfactory completion of a project. This will require

having a collateral property or investment to back up the requirements of the surety agency. A

performance bond is usually issued by a bank or aninsurance company, both of which act as a

“surety.”

Performance Bonds: How They Work?

The Government requires performance bonds and payment bonds for projects to protect

the tax payer’s investment.

Construction Bonds

Performance Bond

Surety Bond

Construction Insurance

Construction Contractors

The private sector also requires the issuance of performance bonds. Common performance and

payments bonds for government projects consist of buildingbridges and roads. If the contractor

does not completion the project specified in the contract the surety bonding company will

either pay for the completion of the project or hire a contracting firm to complete the

project.

A performance bond will protect the owner against possible losses in a case a contractor fails to

perform, or is unable to deliver the project as per established and thecontract provisions.

Sometimes the contractor defaults or declares himself in bankruptcy, and then in those

situations the surety is responsible to compensate the owner for the losses. Such

compensation is defined as the amount covered under the performance bond.

Payment from the performance bond is available only to the project/property owner. No one else

can make claims against it. In order for a performance bond to be effective, the contract must be

specific about the work to be done.

A contractor cannot be held accountable for vague descriptions that are open to interpretation.

Performance Bonds Benefits

Performance bonds ensure that:

The owner of a project is assured of the completion of the project.

The owner does not need to incur additional costs.

There are also some drawbacks with the Performance Bonds. The drawbacks of performance

bonds are:

Sometimes, the surety tries to establish that the owner did not comply with the technical conditions of a

bond to avoid paying the compensation.

Sometimes the surety will try to prove, that the owner may have to settle for the least expensive remedy

to the problem.

The owner needs to quantify the losses that might have been suffered when a trader or contractor fails in

their performance.

If the owner underestimates the losses and the future cost of the completion of the project, the owner may

not be able to recover the shortfall from the surety.

Performance Bonds Requirements

Surety and financial institutions have different requirements depending on the capacity of the

contractor, the volume of the project being ensured and the projects challenges. Usually they

ask for the following:

At least two years of CPA prepared financial statements.

Copy of the contract that is being awarded.

Application of the surety.

If you own real estate, it will help you and will accelerate the process.

Florida Contractor License: How to Become a Licensed Contractor Learn How to Get Your Contractor's License

By Juan Rodriguez

Construction Expert

Hero Images/Getty Images

CONSTRUCTION INDUSTRY LICENSING BOARD

Being a licensed contractor in Florida requires documentation and being certified by the

Construction Industry Licensing Board. The Board is responsible for regulating contractors

and their performance in the construction industry. The Construction Industry Licensing

Board meets regularly to review future member’s applications, analyze and recommend

disciplinary sanctions.

It also participates in rulemaking processes and is also on the look to enforce regulations

and standards among contractors.

Florida Contractor License: Types of License

There two major contractor’s license in the state: Registration and Certification. When the

contractor has obtained a local or city license, then he/she must apply for the initial registration

license. When a contractor has been registered by the Board, then it may only practice in the

city or local area where it permission has been granted. Once the contractor completes and

applies the Florida contractor’s license examination, then the Board might allow you to work

through the state. Both applications can be accessed atwww.myfloridalicense.com.

Contractors practicing general, residential, sheet metal, AC, mechanical, swimming pools,

plumbing, solar, building, underground utility, glass and glazing and pollutant storage activities

require a registration or certification permission from the Board.

Florida Contractor License: Swimming Pools Contractors

The state has one of the most per building ratio of swimming pools in the nation, and for

that reason the Board has created new licenses for contractors engaged in that business.

For example, the Board now includes specialties such as: pool layout, structural pool

design, excavation, trim, pool decking, pool piping and finishes. For these contractor

licenses the state requires a practical test and be at least 18 years old. The board is now

finishing technical paperwork required for this processes.

Florida Contractor License: Being a Certified Contractor

In order to be a Florida Certified Contractor, you must be able to pass the contractor’s test,

provide proven record of financial stability, and present evidence of your experience for the

category in which you wish to be licensed. A contractor must have at least four years of field

experience in the category being considered, and one of those years has to be acting under

a supervisory role. This last requirement could be substituted by at least three years of

undergraduate credit hours. When the contractor wishes to be certified as a building or

general contractor, he/she must present evidence of experience in four of these categories:

Foundations/Slabs in excess of 20,000 square feet

Masonry walls

Steel erection

Elevated slabs

Pre-cast concrete structures

Column erection

Formwork for structural reinforced concrete

In addition to these requirements, contractors must present their past criminal history

information, insurance minimum bonding active at all times ($300K liability, $5k property

damage) or any other amount the contractor boards deemed necessary. Finally, the contractor

must also present active workers’ compensation coverage or an exemption.

Florida Contractor License: Uncategorized Trades

The complexity and variety of construction business is changing day to day. If you want to

be considered a certified contractor, but the trade you perform is not listed by the Board,

you must verify with your local county to see if they offer the type of license you are

requesting. In case the trade being performed is not listed and the work you perform

modifies or created a structure, then a residential, building or general contractor’s license

will be issued. However, the following do not require a state contractor’s license:

Cabinets

Countertops

Flooring

Paint

Wallpaper

Window treatments

Florida Contractor License: Reciprocity

The Florida Contractor’s licensing board offers reciprocity. However, you must first

demonstrate that the exam you passed in your local state is similar or equivalent to Florida’s

or that the requirements on which the contractor license was granted are equivalent to

Florida standards.

Selection of the Best Engineering Firm

By Juan Rodriguez

Construction Expert

Selection of the Best Engineering Firm

Selecting the best engineering firm for your project is a hard task to complete and harder to achieve.

Several companies throughout the nation will try to convince you to use their services, but the best one

will be the one that fulfills your requests.

Engineering Firm: Statement of the Project

Prepare a brief detailed summary of the project. This will help Eengineering firms decide whether or not

participate in your project and to know if they can successfully perform the project you are thinking

about.

It will save you time and money and will discard other companies that might not match your desired skills

and scope of work. This preliminary scope should have:

· The name of the project and location.

· Details like proposed use, capacity and other general related information.

· Funding sources or where the money for the investment will come from.

· Prepare or estimate a calendar and targeted dates.

· Special requirements or restrictions.

· Specialties involved in your project, for example, inspection and management services.

Engineering Firm: Request of Qualification

Once your scope has been elaborated using the guidelines from the previous section, engineering firms

must be invited to submit their credentials and qualifications. Public agencies are required to inform

through massive media, that the request for qualification process has begun. The way it will be informed,

depends on the size and complexity of the project. The contract announcement should include:

· The project description.

· Project’s name and contact person.

· Due dates for submission.

· Special requirements.

· Documentation required from the firms.

Each firm then must submit the information requested along with the names of firm owners, number of

years in business, types of services offered, background on key technical personnel, similar projects

designed by the firm, projects underway, etc.

Evaluation of Qualifications

When the deadline for submission of statements for qualifications has expired, the owner should evaluate

the qualifications of those firms that responded, and narrow the field of interested firms to three to five

firms. Then each firm will be evaluated based in their experience on similar projects, key staff, expertise,

facilities and references.

This process is usually done by a committee or in some instances the architect of the project will conduct

the process. This process should be done by competent professionals that are capable of evaluate several

performances.

Frequently, an owner will emphasize on firms having experience in similar projects and solid

performance along their careers. This can be done weighing their experience, staff, economic and finance

stability and past projects using a balanced formula to select the most suitable engineering firm based on

his requirements.

Engineering Firm: Ranking Process

The final process is the more difficult process of all. The Owner’s opinion has huge importance since the

selection will be based using his criteria and evaluation requirement. When conducting the evaluations,

each committee member ranks the firms, highest to lowest, according to their total scores. The firm that is

rated most highly overall should be notified that it has been selected to receive the contract, pending

agreement on the scope of service and the fee for those services.

Understanding Soft Costs Items included in soft costs on a construction project

By Juan Rodriguez

Construction Expert

Soft Costs constitute a big portion of your construction costs. A construction project is possible

due to the soft costs, that when added to the hard cost and land cost, you will have the total cost

amount for your construction project. Soft costs are traditionally non-seen items that composed

the initial part of developing a construction project.

By Brock Builders

1. Architectural and Design Fees

The architectural and design fee includes costs incurred on feasibility studies, master planning,

design costs, and all other cost included from schematic to project completion.

2. Inspection Fees

Cost of inspections, permits and fees paid to local government.

Land. by Neil Ennis

3. Land Costs

Land costs associated withlegal process, appraisal, real estate,land acquisition,

assessments or improvementsto land related issues.

4. Off-Site

Some projects require to improve conditions in their neighborhood or to complete

improvements to local infrastructure.

5. Equipments

Equipments not being incorporated in the final project delivery.

6. Interests

Cost of loan generated interests.

7. Accounting Fees

All accounting expenses and cost incurred during the development of the construction process.

8. Project Management

Staff required to handle all construction related documentation and drawings.

9. Insurances

All required insurances for the completion of the construction project.

10. Taxes

Money required by state and local agencies depending on the amount of money being invested

in the construction.

Construction Schedule Techniques Construction Scheduling Techniques

By Juan Rodriguez

Construction Expert

Construction ScheduleTechniques

There are many ways in the construction industry to represent and createconstruction

schedulestechniques. Which one is the best for you? We will explain briefly four alternatives that

you can use depending on the project requirements and difficulties.

Construction Schedule: Bar Charts

Bar Charts are the most simple and easiest way to produce a scheduling form in the

construction industry.

It is widely used due to its simplicity and multiple adaptations to numerous events. A bar charts

is formed with a list of activities, specifying the start date, duration of the activity and completion

date of each activity, and then plotted into a the project time scale. The detailed level of the bar

chart will depend on your project complexity and the intended use of the schedule.

A variation of the bar chart schedule, is the linked bar chart. Using a linked bar chart, the

activities and subsequent items are linked with arrows and lines, specifying the sequence and

order of preceding activities. The previous activities are linked one to another to demonstrate

that one activity must be completed before the other activity can start.

Bar charts are useful and commonly used todetect the amount of resources needed for one

particular project. Adding the resources vertically will produce what is called the resource

aggregation. The purpose of this aggregation is to estimate the work production and

establishing estimates for man-hour and equipment needed.

Construction Schedule: Critical Path Method

This process is more elaborated and detailed than the previous one. With a large list of

activities, each activity is then linked to previous and subsequent activities, specifying that each

activity has at least another one that must be completed prior to starting the preceding one.

With the Critical Path Method, calendar days are established and activities are assigned with an

early date, first date that an activity can start; late start, specifying the last possible date that this

activity must be started to avoid delays in the overall construction process; early finish, the

earlier date that the proposed activity will be completed; and the late finish, that is the last date

the activity must be completed without affecting the start of the next one, and subsequently

affecting the entire construction schedule. The steps in producing a network are:

- Listing of activities

- Producing a network showing the logical relationship between activities.

- Assessing the duration of each activity, producing a schedule, and determining the start and

finish times of each activity and the available float

- Assessing the required resources.

Construction Schedule: Line of Balance

This process is a planning technique for repetitive work. The essential procedure for this

scheduling technique is to allocate the resources needed for each step or operation, so the

following activities are not delayed and the result can be obtained. The principles employed are

taken from the planning and control of manufacturing processes greatly modified by E. G.

Trimple. This process is usually applied in the construction work and more specific in road

construction.

Construction Schedule: Q Scheduling

Q. Scheduling is quantitative scheduling, in the context that quantities to be executed at

different locations of the construction project form the elements of the schedule. Also Q.

Scheduling is Queue Scheduling in the context that trades pass through the different segments

of the project in a queue sequence. No interference between two activities is allowed at the

same location. It is derived basically from the Line of balance technique with some

modifications to allow for the non repetitive models that are characteristic of the majority of

construction projects.

The Q Scheduling is a new technique, though getting rapid popularity among contracting firms.

It is the only scheduling technique that reveals a relation between the sequence of doing a job

and the cost to be incurred. The Q schedule is similar to the Line of Balance with some

modifications, to allow for a varying volume of repetitive activities at different segments or

locations of the construction project, thus the model produced is closer to reality.

Contract: Construction Contract Basics Construction Contract Basics

By Juan Rodriguez

Construction Expert

Construction contracts can be a very useful tool that every builder must know to perfection.

There are different types of contracts, tips and guidelines that must form part of every

construction contract. Contracting agents are a vital part of the construction industry, but

following these guidelines you can become one great contracting leader.

1. Contract Documents The contract documents are one of the most important pieces that will guarantee of a successful

project. This list contains the most common documents that must form part of every

construction contract.More »

Which contract to use?

2. Contract Types There are a several types of construction contracts used in the industry, but there are certain

types of construction contracts preferred by construction professionals.More »

3. Union Contracts A labor union contract is a powerful agreement between parts to secure your rights in the

workplace. According to labor law, contracts represent the minimum compensation and

benefits for employees. More »

4. Contract: Direct Hire or Sub-Contract Subcontracting can offer you some warranties and hiring someone directly will require

additional efforts from you. But what is the best decision? More »

5. Contract Key Rules When you're ready to negotiate with the company regarding benefits, wages and work

conditions, use the following steps to generate productive talks. More »

6. Contract Negotiation Process The negotiating of a contract is a stressful time, and it will drain you mentally and physically.

Follow these steps to help you reduce the time dedicated to the process.More »

General Scaffold Requirements

By Juan Rodriguez

Construction Expert

List of general scaffold requirements in the construction industry. This list is for informational

purposes only and might not be used as a standard. For more information, regulations and

standard's visit OSHA's website.

Scaffold components must be able to support at least four times their maximum intended load.

The scaffolding platform should be fully planked, with no more than a 1-inch gap between planks and

uprights.

The gap between the last plank and the uprights should be less than 9½ inches.

18 inches is the minimum wide dimension allowed on platforms.

The scaffold should be 14 inches or less from the work face, or 18 inches for plastering and lathing.

12 inches is the maximum extension permitted for planks beyond the frames.

Casters must be locked before work begins.

Platform surfaces should be secured.

The platform should be free from any object that may cause an accident.

Power lines must be at least 10 feet awayfrom scaffolding, material and workers.

Different manufacturers of scaffolding components can be used, but they must fit together without force.

A defective scaffold must be removed from service immediately.

Indemnity Agreements Three common types of indemnity agreements.

By Juan Rodriguez

Construction Expert

Indemnity Agreement in Construction Contracts

An Indemnity agreement can protect you and allow others to bear the costs associated with damages.

An indemnity agreement will reduce your construction risks and can control your total legal expenses. It

is important that the agreement itself can describe the types of losses being covered, including legal

fees. Some states do not favor indemnity agreements and present limitations to indemnity agreements.

It is very important that the agreement properly identifies the scope and extent of the indemnification.

This type of agreement is developed to protect the contractor less active under one particular trade or

series of events.

Types of Indemnity Clauses

Every indemnity agreement should be prepared accordingly to the type of project being executed. The

most common indemnity clauses are:

Type I

Also known as a Broad Form Indemnity. Under this clause the indemnitor is responsible for his own negligence as

well as the negligence of a third party. This means that the indemnitor may be liable for the sole negligence of the

indemnitee. In some states, such as California, the indemnitee cannot transfer damages caused by his sole negligence

or willful misconduct to the indemnitor.

Type II

The type II or intermediate form of agreements will put the indemnitor assuming all the risks associated but not if

the risk is the indemnitee responsibility. It is the preferred clause in the construction industry and could hold the

owner harmless from any and all claims, caused by negligent acts or omissions of the owner. It requires all-or-

nothing indemnification.

Textured Bricks and Blocks.Any Colour or Geometry.Highly Durable.

Type III

A Type III or a comparative form clauserequires a comparison of negligence. Under this clause the indemnitor will

be held responsible for the loss caused by the indemnitor. This Type Three agreement is based upon common law

principalscommonly recognized in the United States. The indemnitor is not liable for direct negligence committed by

the indemnitee.

Other Types of Indemnity Clauses

A work related clause, rarely used, doesn't requires an act of negligence or omission. It only depends on whether the

work was being performed by the subcontractor.

A mutual clause applies the same standard to each party, the indemnitor and the indemnitee.

Indemnity Clause Claims

An indemnity clause can be used for the following purposes:

Breach of Contract

Liability for negligence

Compensation due to injuries or property damages.

Claims for loss.

All types of property infringement.

Legal costs and related expenses.

Loss of profit.

Taxes and interests payable by a default contractor.

Indemnity Clause Contract Forms

The AIA Document A401 'Standard Form of Agreement Between Contractor and Subcontractor' states

and provides for indemnity as follows:

'§ 4.3.4 To the fullest extent permitted by law, the Contractor shall indemnify and hold harmless the

Subcontractor, the Subcontractor's Sub-subcontractors, and agents and employees of any of them from

and against claims, damages, losses and expenses, including but not limited to attorneys' fees, arising out

of or resulting from performance of the Work in the affected area if in fact the material or substance

presents the risk of bodily injury or death as described in Section 4.3.3 and has not been rendered

harmless, provided that such claim, damage, loss or expense is attributable to bodily injury, sickness,

disease or death, or to injury to or destruction of tangible property (other than the Work itself) except to

the extent that such damage, loss or expense is due to the fault or negligence of the party seeking

indemnity.

§ 4.3.5 The Subcontractor shall indemnify the Contractor for the cost and expense the Contractor incurs

(1) for remediation of a material or substance brought to the site and negligently handled by the

Subcontractor or (2) where the Subcontractor fails to perform its obligations under Section 4.3.3, except

to the extent that the cost and expenses are due to the Contractor's fault or negligence.'

If you decide to use ConsensusDOCS 'Standard Form of Agreement Between Contractor and

Subcontractor',ConsensusDocs 750, you will also be covered with an indemnity clause specified under

section 9.1.1 and 9.1.2.

Both of these contract forms limit the subcontractor's obligation to indemnify the contractor. This

last form, imposes additional indemnity obligations not covered under the AIA A401 form. In addition to

these clauses it is very important to consider all other insurance requirements.

9. Construction Planning

9.1 Basic Concepts in the Development of Construction Plans

Construction planning is a fundamental and challenging activity in the management

and execution of construction projects. It involves the choice of technology, the

definition of work tasks, the estimation of the required resources and durations for

individual tasks, and the identification of any interactions among the different work

tasks. A good construction plan is the basis for developing the budget and the

schedule for work. Developing the construction plan is a critical task in the

management of construction, even if the plan is not written or otherwise formally

recorded. In addition to these technical aspects of construction planning, it may also

be necessary to make organizational decisions about the relationships between project

participants and even which organizations to include in a project. For example, the

extent to which sub-contractors will be used on a project is often determined during

construction planning.

Forming a construction plan is a highly challenging task. As Sherlock Holmes noted:

Most people, if you describe a train of events to them, will tell you what the result

would be. They can put those events together in their minds, and argue from them that

something will come to pass. There are few people, however, who, if you told them a

result, would be able to evolve from their own inner consciousness what the steps

were which led up to that result. This power is what I mean when I talk of reasoning

backward. [1]

Like a detective, a planner begins with a result (i.e. a facility design) and must

synthesize the steps required to yield this result. Essential aspects of construction

planning include the generation of required activities, analysis of the implications of

these activities, and choice among the various alternative means of performing

activities. In contrast to a detective discovering a single train of events, however,

construction planners also face the normative problem of choosing the best among

numerous alternative plans. Moreover, a detective is faced with an observable result,

whereas a planner must imagine the final facility as described in the plans and

specifications.

In developing a construction plan, it is common to adopt a primary emphasis on either

cost control or on schedule control as illustrated in Fig. 9-1. Some projects are

primarily divided into expense categories with associated costs. In these cases,

construction planning is cost or expense oriented. Within the categories of

expenditure, a distinction is made between costs incurred directly in the performance

of an activity and indirectly for the accomplishment of the project. For example,

borrowing expenses for project financing and overhead items are commonly treated as

indirect costs. For other projects, scheduling of work activities over time is critical

and is emphasized in the planning process. In this case, the planner insures that the

proper precedences among activities are maintained and that efficient scheduling of

the available resources prevails. Traditional scheduling procedures emphasize the

maintenance of task precedences (resulting in critical path scheduling procedures) or

efficient use of resources over time (resulting in job shop scheduling procedures).

Finally, most complex projects require consideration of both cost and scheduling over

time, so that planning, monitoring and record keeping must consider both dimensions.

In these cases, the integration of schedule and budget information is a major concern.

Figure 9-1 Alternative Emphases in Construction Planning

In this chapter, we shall consider the functional requirements for construction

planning such as technology choice, work breakdown, and budgeting. Construction

planning is not an activity which is restricted to the period after the award of a

contract for construction. It should be an essential activity during the facility design.

Also, if problems arise during construction, re-planning is required.

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9.2 Choice of Technology and Construction Method

As in the development of appropriate alternatives for facility design, choices of

appropriate technology and methods for construction are often ill-structured yet

critical ingredients in the success of the project. For example, a decision whether to

pump or to transport concrete in buckets will directly affect the cost and duration of

tasks involved in building construction. A decision between these two alternatives

should consider the relative costs, reliabilities, and availability of equipment for the

two transport methods. Unfortunately, the exact implications of different methods

depend upon numerous considerations for which information may be sketchy during

the planning phase, such as the experience and expertise of workers or the particular

underground condition at a site.

In selecting among alternative methods and technologies, it may be necessary to

formulate a number of construction plans based on alternative methods or

assumptions. Once the full plan is available, then the cost, time and reliability impacts

of the alternative approaches can be reviewed. This examination of several

alternatives is often made explicit in bidding competitions in which several alternative

designs may be proposed or value engineering for alternative construction methods

may be permitted. In this case, potential constructors may wish to prepare plans for

each alternative design using the suggested construction method as well as to prepare

plans for alternative construction methods which would be proposed as part of the

value engineering process.

In forming a construction plan, a useful approach is to simulate the construction

process either in the imagination of the planner or with a formal computer based

simulation technique. [2] By observing the result, comparisons among different plans

or problems with the existing plan can be identified. For example, a decision to use a

particular piece of equipment for an operation immediately leads to the question of

whether or not there is sufficient access space for the equipment. Three dimensional

geometric models in a computer aided design (CAD) system may be helpful in

simulating space requirements for operations and for identifying any interferences.

Similarly, problems in resource availability identified during the simulation of the

construction process might be effectively forestalled by providing additional resources

as part of the construction plan.

Example 9-1: A roadway rehabilitation

An example from a roadway rehabilitation project in Pittsburgh, PA can serve to

illustrate the importance of good construction planning and the effect of technology

choice. In this project, the decks on overpass bridges as well as the pavement on the

highway itself were to be replaced. The initial construction plan was to work outward

from each end of the overpass bridges while the highway surface was replaced

below the bridges. As a result, access of equipment and concrete trucks to the

overpass bridges was a considerable problem. However, the highway work could be

staged so that each overpass bridge was accessible from below at prescribed times.

By pumping concrete up to the overpass bridge deck from the highway below, costs

were reduced and the work was accomplished much more quickly.

Example 9-2: Laser Leveling

An example of technology choice is the use of laser leveling equipment to improve

the productivity of excavation and grading. [3] In these systems, laser surveying

equipment is erected on a site so that the relative height of mobile equipment is

known exactly. This height measurement is accomplished by flashing a rotating laser

light on a level plane across the construction site and observing exactly where the

light shines on receptors on mobile equipment such as graders. Since laser light does

not disperse appreciably, the height at which the laser shines anywhere on the

construction site gives an accurate indication of the height of a receptor on a piece

of mobile equipment. In turn, the receptor height can be used to measure the height

of a blade, excavator bucket or other piece of equipment. Combined with electro-

hydraulic control systems mounted on mobile equipment such as bulldozers, graders

and scrapers, the height of excavation and grading blades can be precisely and

automatically controlled in these systems. This automation of blade heights has

reduced costs in some cases by over 80% and improved quality in the finished

product, as measured by the desired amount of excavation or the extent to which a

final grade achieves the desired angle. These systems also permit the use of smaller

machines and less skilled operators. However, the use of these semi-automated

systems require investments in the laser surveying equipment as well as modification

to equipment to permit electronic feedback control units. Still, laser leveling appears

to be an excellent technological choice in many instances.

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9.3 Defining Work Tasks

At the same time that the choice of technology and general method are considered, a

parallel step in the planning process is to define the various work tasks that must be

accomplished. These work tasks represent the necessary framework to

permit scheduling of construction activities, along with estimating

the resources required by the individual work tasks, and any necessary precedences or

required sequence among the tasks. The terms work "tasks" or "activities" are often

used interchangeably in construction plans to refer to specific, defined items of work.

In job shop or manufacturing terminology, a project would be called a "job" and an

activity called an "operation", but the sense of the terms is

equivalent. [4] The scheduling problem is to determine an appropriate set of activity

start time, resource allocations and completion times that will result in completion of

the project in a timely and efficient fashion. Construction planning is the necessary

fore-runner to scheduling. In this planning, defining work tasks, technology and

construction method is typically done either simultaeously or in a series of iterations.

The definition of appropriate work tasks can be a laborious and tedious process, yet it

represents the necessary information for application of formal scheduling procedures.

Since construction projects can involve thousands of individual work tasks, this

definition phase can also be expensive and time consuming. Fortunately, many tasks

may be repeated in different parts of the facility or past facility construction plans can

be used as general models for new projects. For example, the tasks involved in the

construction of a building floor may be repeated with only minor differences for each

of the floors in the building. Also, standard definitions and nomenclatures for most

tasks exist. As a result, the individual planner defining work tasks does not have to

approach each facet of the project entirely from scratch.

While repetition of activities in different locations or reproduction of activities from

past projects reduces the work involved, there are very few computer aids for the

process of defining activities. Databases and information systems can assist in the

storage and recall of the activities associated with past projects as described in

Chapter 14. For the scheduling process itself, numerous computer programs are

available. But for the important task of defining activities, reliance on the skill,

judgment and experience of the construction planner is likely to continue.

More formally, an activity is any subdivision of project tasks. The set of activities

defined for a project should be comprehensive or completely exhaustive so that all

necessary work tasks are included in one or more activities. Typically, each design

element in the planned facility will have one or more associated project activities.

Execution of an activity requires time and resources, including manpower and

equipment, as described in the next section. The time required to perform an activity

is called the duration of the activity. The beginning and the end of activities are

signposts or milestones, indicating the progress of the project. Occasionally, it is

useful to define activities which have no duration to mark important events. For

example, receipt of equipment on the construction site may be defined as an activity

since other activities would depend upon the equipment availability and the project

manager might appreciate formal notice of the arrival. Similarly, receipt of regulatory

approvals would also be specially marked in the project plan.

The extent of work involved in any one activity can vary tremendously in construction

project plans. Indeed, it is common to begin with fairly coarse definitions of activities

and then to further sub-divide tasks as the plan becomes better defined. As a result,

the definition of activities evolves during the preparation of the plan. A result of this

process is a natural hierarchy of activities with large, abstract functional activities

repeatedly sub-divided into more and more specific sub-tasks. For example, the

problem of placing concrete on site would have sub-activities associated with placing

forms, installing reinforcing steel, pouring concrete, finishing the concrete, removing

forms and others. Even more specifically, sub-tasks such as removal and cleaning of

forms after concrete placement can be defined. Even further, the sub-task "clean

concrete forms" could be subdivided into the various operations:

Transport forms from on-site storage and unload onto the cleaning station. Position forms on the cleaning station. Wash forms with water. Clean concrete debris from the form's surface. Coat the form surface with an oil release agent for the next use. Unload the form from the cleaning station and transport to the storage

location.

This detailed task breakdown of the activity "clean concrete forms" would not

generally be done in standard construction planning, but it is essential in the process

of programming or designing a robot to undertake this activity since the various

specific tasks must be well defined for a robot implementation. [5]

It is generally advantageous to introduce an explicit hierarchy of work activities for

the purpose of simplifying the presentation and development of a schedule. For

example, the initial plan might define a single activity associated with "site

clearance." Later, this single activity might be sub-divided into "re-locating utilities,"

"removing vegetation," "grading", etc. However, these activities could continue to be

identified as sub-activities under the general activity of "site clearance." This

hierarchical structure also facilitates the preparation of summary charts and reports in

which detailed operations are combined into aggregate or "super"-activities.

More formally, a hierarchical approach to work task definition decomposes the work

activity into component parts in the form of a tree. Higher levels in the tree represent

decision nodes or summary activities, while branches in the tree lead to smaller

components and work activities. A variety of constraints among the various nodes

may be defined or imposed, including precedence relationships among different tasks

as defined below. Technology choices may be decomposed to decisions made at

particular nodes in the tree. For example, choices on plumbing technology might be

made without reference to choices for other functional activities.

Of course, numerous different activity hierarchies can be defined for each

construction plan. For example, upper level activities might be related to facility

components such as foundation elements, and then lower level activity divisions into

the required construction operations might be made. Alternatively, upper level

divisions might represent general types of activities such as electrical work, while

lower work divisions represent the application of these operations to specific facility

components. As a third alternative, initial divisions might represent different spatial

locations in the planned facility. The choice of a hierarchy depends upon the desired

scheme for summarizing work information and on the convenience of the planner. In

computerized databases, multiple hierarchies can be stored so that different

aggregations or views of the work breakdown structure can be obtained.

The number and detail of the activities in a construction plan is a matter of judgment

or convention. Construction plans can easily range between less than a hundred to

many thousand defined tasks, depending on the planner's decisions and the scope of

the project. If subdivided activities are too refined, the size of the network becomes

unwieldy and the cost of planning excessive. Sub-division yields no benefit if

reasonably accurate estimates of activity durations and the required resources cannot

be made at the detailed work breakdown level. On the other hand, if the specified

activities are too coarse, it is impossible to develop realistic schedules and details of

resource requirements during the project. More detailed task definitions permit better

control and more realistic scheduling. It is useful to define separate work tasks for:

those activities which involve different resources, or those activities which do not require continuous performance.

For example, the activity "prepare and check shop drawings" should be divided into a

task for preparation and a task for checking since different individuals are involved in

the two tasks and there may be a time lag between preparation and checking.

In practice, the proper level of detail will depend upon the size, importance and

difficulty of the project as well as the specific scheduling and accounting procedures

which are adopted. However, it is generally the case that most schedules are prepared

with too little detail than too much. It is important to keep in mind that task definition

will serve as the basis for scheduling, for communicating the construction plan and for

construction monitoring. Completion of tasks will also often serve as a basis for

progress payments from the owner. Thus, more detailed task definitions can be quite

useful. But more detailed task breakdowns are only valuable to the extent that the

resources required, durations and activity relationships are realistically estimated for

each activity. Providing detailed work task breakdowns is not helpful without a

commensurate effort to provide realistic resource requirement estimates. As more

powerful, computer-based scheduling and monitoring procedures are introduced, the

ease of defining and manipulating tasks will increase, and the number of work tasks

can reasonably be expected to expand.

Example 9-3: Task Definition for a Road Building Project

As an example of construction planning, suppose that we wish to develop a plan for

a road construction project including two culverts. [6] Initially, we divide project

activities into three categories as shown in Figure 9-2: structures, roadway, and

general. This division is based on the major types of design elements to be

constructed. Within the roadway work, a further sub-division is into earthwork and

pavement. Within these subdivisions, we identify clearing, excavation, filling and

finishing (including seeding and sodding) associated with earthwork, and we define

watering, compaction and paving sub-activities associated with pavement. Finally,

we note that the roadway segment is fairly long, and so individual activities can be

defined for different physical segments along the roadway path. In Figure 9-2, we

divide each paving and earthwork activity into activities specific to each of two

roadway segments. For the culvert construction, we define the sub-divisions of

structural excavation, concreting, and reinforcing. Even more specifically, structural

excavation is divided into excavation itself and the required backfill and compaction.

Similarly, concreting is divided into placing concrete forms, pouring concrete,

stripping forms, and curing the concrete. As a final step in the structural planning,

detailed activities are defined for reinforcing each of the two culverts. General work

activities are defined for move in, general supervision, and clean up. As a result of

this planning, over thirty different detailed activities have been defined.

At the option of the planner, additional activities might also be defined for this

project. For example, materials ordering or lane striping might be included as separate

activities. It might also be the case that a planner would define a different hierarchy of

work breakdowns than that shown in Figure 9-2. For example, placing reinforcing

might have been a sub-activity under concreting for culverts. One reason for

separating reinforcement placement might be to emphasize the different material and

resources required for this activity. Also, the division into separate roadway segments

and culverts might have been introduced early in the hierarchy. With all these

potential differences, the important aspect is to insure that all necessary activities are

included somewhere in the final plan.

Figure 9-2 Illustrative Hierarchical Activity Divisions for a Roadway Project

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9.4 Defining Precedence Relationships Among Activities

Once work activities have been defined, the relationships among the activities can be

specified. Precedence relations between activities signify that the activities must take

place in a particular sequence. Numerous natural sequences exist for construction

activities due to requirements for structural integrity, regulations, and other technical

requirements. For example, design drawings cannot be checked before they are drawn.

Diagramatically, precedence relationships can be illustrated by a network or graph in

which the activities are represented by arrows as in Figure 9-0. The arrows in Figure

9-3 are calledbranches or links in the activity network, while the circles marking the

beginning or end of each arrow are called nodes or events. In this figure, links

represent particular activities, while the nodes represent milestone events.

Figure 9-3 Illustrative Set of Four Activities with Precedences

More complicated precedence relationships can also be specified. For example, one

activity might not be able to start for several days after the completion of another

activity. As a common example, concrete might have to cure (or set) for several days

before formwork is removed. This restriction on the removal of forms activity is

called a lag between the completion of one activity (i.e., pouring concrete in this case)

and the start of another activity (i.e., removing formwork in this case). Many

computer based scheduling programs permit the use of a variety of precedence

relationships.

Three mistakes should be avoided in specifying predecessor relationships for

construction plans. First, a circle of activity precedences will result in an impossible

plan. For example, if activity A precedes activity B, activity B precedes activity C,

and activity C precedes activity A, then the project can never be started or completed!

Figure 9-4 illustrates the resulting activity network. Fortunately, formal scheduling

methods and good computer scheduling programs will find any such errors in the

logic of the construction plan.

Figure 9-4 Example of an Impossible Work Plan

Forgetting a necessary precedence relationship can be more insidious. For example,

suppose that installation of dry wall should be done prior to floor finishing. Ignoring

this precedence relationship may result in both activities being scheduled at the same

time. Corrections on the spot may result in increased costs or problems of quality in

the completed project. Unfortunately, there are few ways in which precedence

omissions can be found other than with checks by knowledgeable managers or by

comparison to comparable projects. One other possible but little used mechanism for

checking precedences is to conduct a physical or computer based simulation of the

construction process and observe any problems.

Finally, it is important to realize that different types of precedence relationships can

be defined and that each has different implications for the schedule of activities:

Some activities have a necessary technical or physical relationship that cannot be superseded. For example, concrete pours cannot proceed before formwork and reinforcement are in place.

Some activities have a necessary precedence relationship over a continuous space rather than as discrete work task relationships. For example, formwork may be placed in the first part of an excavation trench even as the excavation equipment continues to work further along in the trench. Formwork placement cannot proceed further than the excavation, but the two activities can be started and stopped independently within this constraint.

Some "precedence relationships" are not technically necessary but are imposed due to implicit decisions within the construction plan. For example, two activities may require the same piece of equipment so a precedence relationship might be defined between the two to insure that they are not scheduled for the same time period. Which activity is scheduled first is

arbitrary. As a second example, reversing the sequence of two activities may be technically possible but more expensive. In this case, the precedence relationship is not physically necessary but only applied to reduce costs as perceived at the time of scheduling.

In revising schedules as work proceeds, it is important to realize that different types of

precedence relationships have quite different implications for the flexibility and cost

of changing the construction plan. Unfortunately, many formal scheduling systems do

not possess the capability of indicating this type of flexibility. As a result, the burden

is placed upon the manager of making such decisions and insuring realistic and

effective schedules. With all the other responsibilities of a project manager, it is no

surprise that preparing or revising the formal, computer based construction plan is a

low priority to a manager in such cases. Nevertheless, formal construction plans may

be essential for good management of complicated projects.

Example 9-4: Precedence Definition for Site Preparation and Foundation Work

Suppose that a site preparation and concrete slab foundation construction project

consists of nine different activities:

A. Site clearing (of brush and minor debris),

B. Removal of trees,

C. General excavation,

D. Grading general area,

E. Excavation for utility trenches,

F. Placing formwork and reinforcement for concrete,

G. Installing sewer lines,

H. Installing other utilities,

I. Pouring concrete.

Activities A (site clearing) and B (tree removal) do not have preceding activities since

they depend on none of the other activities. We assume that activities C (general

excavation) and D (general grading) are preceded by activity A (site clearing). It

might also be the case that the planner wished to delay any excavation until trees were

removed, so that B (tree removal) would be a precedent activity to C (general

excavation) and D (general grading). Activities E (trench excavation) and F (concrete

preparation) cannot begin until the completion of general excavation and tree removal,

since they involve subsequent excavation and trench preparation. Activities G (install

lines) and H (install utilities) represent installation in the utility trenches and cannot be

attempted until the trenches are prepared, so that activity E (trench excavation) is a

preceding activity. We also assume that the utilities should not be installed until

grading is completed to avoid equipment conflicts, so activity D (general grading) is

also preceding activities G (install sewers) and H (install utilities). Finally, activity I

(pour concrete) cannot begin until the sewer line is installed and formwork and

reinforcement are ready, so activities F and G are preceding. Other utilities may be

routed over the slab foundation, so activity H (install utilities) is not necessarily a

preceding activity for activity I (pour concrete). The result of our planning are the

immediate precedences shown in Table 9-1.

TABLE 9-1 Precedence Relations for a Nine-Activity Project Example

Activity Description Predecessors

A

B

C

D

E

F

G

H

I

Site clearing

Removal of trees

General excavation

Grading general area

Excavation for utility trenches

Placing formwork and reinforcement for concrete

Installing sewer lines

Installing other utilities

Pouring concrete

---

---

A

A

B,C

B,C

D,E

D,E

F,G

With this information, the next problem is to represent the activities in a network

diagram and to determine all the precedence relationships among the activities. One

network representation of these nine activities is shown in Figure 9-5, in which the

activities appear as branches or links between nodes. The nodes represent milestones

of possible beginning and starting times. This representation is called an activity-on-

branch diagram. Note that an initial event beginning activity is defined (Node 0 in

Figure 9-5), while node 5 represents the completion of all activities.

Figure 9-5 Activity-on-Branch Representation of a Nine Activity Project

Alternatively, the nine activities could be represented by nodes and predecessor

relationships by branches or links, as in Figure 9-6. The result is an activity-on-

node diagram. In Figure 9-6, new activity nodes representing the beginning and the

end of construction have been added to mark these important milestones.

These network representations of activities can be very helpful in visualizing the

various activities and their relationships for a project. Whether activities are

represented as branches (as in Figure 9-5) or as nodes (as in Figure 9-5) is largely a

matter of organizational or personal choice. Some considerations in choosing one

form or another are discussed in Chapter 10.

Figure 9-6 Activity-on-Node Representation of a Nine Activity Project

It is also notable that Table 9-1 lists only the immediate predecessor relationships.

Clearly, there are other precedence relationships which involve more than one

activity. For example, "installing sewer lines" (activity G) cannot be undertaken

before "site clearing" (Activity A) is complete since the activity "grading general

area" (Activity D) must precede activity G and must follow activity A. Table 9-1 is

an implicit precedence list since only immediate predecessors are recorded. An

explicit predecessor list would include all of the preceding activities for activity G.

Table 9-2 shows all such predecessor relationships implied by the project plan. This

table can be produced by tracing all paths through the network back from a particular

activity and can be performed algorithmically. [7] For example, inspecting Figure 9-6

reveals that each activity except for activity B depends upon the completion of

activity A.

TABLE 9-2 All Activity Precedence Relationships for a Nine-Activity Project

Predecessor Activity Direct Successor Activities All Successor Activities All Predecessor Activities

A

B

C,D

E,F

E,F,G,H,I

G,H,I

---

---

C

D

E

F

G

H

I

E,F

G,H

G,H

I

I

---

---

G,H,I

I

I

---

---

---

---

A

A

A,B,C

A,B,C

A,B,C,D,E

A,B,C,D,E

A,B,C,D,E,F,G

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9.5 Estimating Activity Durations

In most scheduling procedures, each work activity has an associated time duration.

These durations are used extensively in preparing a schedule. For example, suppose

that the durations shown in Table 9-3 were estimated for the project diagrammed in

Figure 9-0. The entire set of activities would then require at least 3 days, since the

activities follow one another directly and require a total of 1.0 + 0.5 + 0.5 + 1.0 = 3

days. If another activity proceeded in parallel with this sequence, the 3 day minimum

duration of these four activities is unaffected. More than 3 days would be required for

the sequence if there was a delay or a lag between the completion of one activity and

the start of another.

TABLE 9-3 Durations and Predecessors for a Four Activity Project Illustration

Activity Predecessor Duration (Days)

Excavate trench

Place formwork

Place reinforcing

Pour concrete

---

Excavate trench

Place formwork

Place reinforcing

1.0

0.5

0.5

1.0

All formal scheduling procedures rely upon estimates of the durations of the various

project activities as well as the definitions of the predecessor relationships among

tasks. The variability of an activity's duration may also be considered. Formally,

the probability distribution of an activity's duration as well as the expected or most

likely duration may be used in scheduling. A probability distribution indicates the

chance that a particular activity duration will occur. In advance of actually doing a

particular task, we cannot be certain exactly how long the task will require.

A straightforward approach to the estimation of activity durations is to keep historical

records of particular activities and rely on the average durations from this experience

in making new duration estimates. Since the scope of activities are unlikely to be

identical between different projects, unit productivity rates are typically employed for

this purpose. For example, the duration of an activity Dij such as concrete formwork

assembly might be estimated as:

(9.1)

where Aij is the required formwork area to assemble (in square yards), Pij is the

average productivity of a standard crew in this task (measured in square yards per

hour), and Nij is the number of crews assigned to the task. In some organizations, unit

production time, Tij, is defined as the time required to complete a unit of work by a

standard crew (measured in hours per square yards) is used as a productivity measure

such that Tij is a reciprocal of Pij.

A formula such as Eq. (9.1) can be used for nearly all construction activities.

Typically, the required quantity of work, Aij is determined from detailed examination

of the final facility design. This quantity-take-off to obtain the required amounts of

materials, volumes, and areas is a very common process in bid preparation by

contractors. In some countries, specialized quantity surveyors provide the information

on required quantities for all potential contractors and the owner. The number of

crews working, Nij, is decided by the planner. In many cases, the number or amount of

resources applied to particular activities may be modified in light of the resulting

project plan and schedule. Finally, some estimate of the expected work productivity,

Pij must be provided to apply Equation (9.1). As with cost factors, commercial

services can provide average productivity figures for many standard activities of this

sort. Historical records in a firm can also provide data for estimation of productivities.

The calculation of a duration as in Equation (9.1) is only an approximation to the

actual activity duration for a number of reasons. First, it is usually the case that

peculiarities of the project make the accomplishment of a particular activity more or

less difficult. For example, access to the forms in a particular location may be

difficult; as a result, the productivity of assembling forms may be lower than the

average value for a particular project. Often, adjustments based on engineering

judgment are made to the calculated durations from Equation (9.1) for this reason.

In addition, productivity rates may vary in both systematic and random fashions from

the average. An example of systematic variation is the effect of learning on

productivity. As a crew becomes familiar with an activity and the work habits of the

crew, their productivity will typically improve. Figure 9-7 illustrates the type of

productivity increase that might occur with experience; this curve is called alearning

curve. The result is that productivity Pij is a function of the duration of an activity or

project. A common construction example is that the assembly of floors in a building

might go faster at higher levels due to improved productivity even though the

transportation time up to the active construction area is longer. Again, historical

records or subjective adjustments might be made to represent learning curve

variations in average productivity. [8]

Figure 9-7 Illustration of Productivity Changes Due to Learning

Random factors will also influence productivity rates and make estimation of activity

durations uncertain. For example, a scheduler will typically not know at the time of

making the initial schedule how skillful the crew and manager will be that are

assigned to a particular project. The productivity of a skilled designer may be many

times that of an unskilled engineer. In the absence of specific knowledge, the

estimator can only use average values of productivity.

Weather effects are often very important and thus deserve particular attention in

estimating durations. Weather has both systematic and random influences on activity

durations. Whether or not a rainstorm will come on a particular day is certainly a

random effect that will influence the productivity of many activities. However, the

likelihood of a rainstorm is likely to vary systematically from one month or one site to

the next. Adjustment factors for inclement weather as well as meteorological records

can be used to incorporate the effects of weather on durations. As a simple example,

an activity might require ten days in perfect weather, but the activity could not

proceed in the rain. Furthermore, suppose that rain is expected ten percent of the days

in a particular month. In this case, the expected activity duration is eleven days

including one expected rain day.

Finally, the use of average productivity factors themselves cause problems in the

calculation presented in Equation (9.1). The expected value of the multiplicative

reciprocal of a variable is not exactly equal to the reciprocal of the variable's expected

value. For example, if productivity on an activity is either six in good weather (ie.,

P=6) or two in bad weather (ie., P=2) and good or bad weather is equally likely, then

the expected productivity is P = (6)(0.5) + (2)(0.5) = 4, and the reciprocal of expected

productivity is 1/4. However, the expected reciprocal of productivity is E[1/P] =

(0.5)/6 + (0.5)/2 = 1/3. The reciprocal of expected productivity is 25% less than the

expected value of the reciprocal in this case! By representing only two possible

productivity values, this example represents an extreme case, but it is always true that

the use of average productivity factors in Equation (9.1) will result

in optimistic estimates of activity durations. The use of actual averages for the

reciprocals of productivity or small adjustment factors may be used to correct for this

non-linearity problem.

The simple duration calculation shown in Equation (9.1) also assumes an inverse

linear relationship between the number of crews assigned to an activity and the total

duration of work. While this is a reasonable assumption in situations for which crews

can work independently and require no special coordination, it need not always be

true. For example, design tasks may be divided among numerous architects and

engineers, but delays to insure proper coordination and communication increase as the

number of workers increase. As another example, insuring a smooth flow of material

to all crews on a site may be increasingly difficult as the number of crews increase. In

these latter cases, the relationship between activity duration and the number of crews

is unlikely to be inversely proportional as shown in Equation (9.1). As a result,

adjustments to the estimated productivity from Equation (9.1) must be made.

Alternatively, more complicated functional relationships might be estimated between

duration and resources used in the same way that nonlinear preliminary or conceptual

cost estimate models are prepared.

One mechanism to formalize the estimation of activity durations is to employ a

hierarchical estimation framework. This approach decomposes the estimation problem

into component parts in which the higher levels in the hierarchy represent attributes

which depend upon the details of lower level adjustments and calculations. For

example, Figure 9-8 represents various levels in the estimation of the duration of

masonry construction. [9] At the lowest level, the maximum productivity for the

activity is estimated based upon general work conditions. Table 9-4 illustrates some

possible maximum productivity values that might be employed in this estimation. At

the next higher level, adjustments to these maximum productivities are made to

account for special site conditions and crew compositions; table 9-5 illustrates some

possible adjustment rules. At the highest level, adjustments for overall effects such as

weather are introduced. Also shown in Figure 9-8 are nodes to estimate down or

unproductive time associated with the masonry construction activity. The

formalization of the estimation process illustrated in Figure 9-8 permits the

development of computer aids for the estimation process or can serve as a conceptual

framework for a human estimator.

TABLE 9-4 Maximum Productivity Estimates for Masonry Work

Masonry unit

size Condition(s)

Maximum produstivity

achievable

8 inch block None 400 units/day/mason

6 inch Wall is "long" 430 units/day/mason

6 inch Wall is not "long" 370 units/day/mason

12 inch Labor is nonunion 300 units/day/mason

4 inch Wall is "long"

Weather is "warm and dry"

or high-strength mortar is used

480 units/day/mason

4 inch Wall is not "long"

Weather is "warm and dry"

or high-strength mortar is used

430 units/day/mason

4 inch Wall is "long"

Weather is not "warm and dry"

or high-strength mortar is not

used

370 units/day/mason

4 inch Wall is not "long"

Weather is not "warm and dry"

or high-strength mortar is not

used

320 units/day/mason

8 inch There is support from existing

wall

1,000 units/day/mason

8 inch There is no support from existing 750 units/day/mason

wall

12 inch There is support from existing

wall

700 units/day/mason

12 inch There is no support from existing

wall

550

TABLE 9-5 Possible Adjustments to Maximum Productivities for Masonry

Construction/caption>

Impact Condition(s)

Adjustment

magnitude

(% of maximum)

Crew type Crew type is nonunion

Job is "large"

15%

Crew type Crew type is union

Job is "small"

10%

Supporting

labor

There are less than two laborers per crew 20%

Supporting

labor

There are more than two masons/laborers 10%

Elevation Steel frame building with masonry exterior

wall has "insufficient" support labor

10%

Elevation Solid masonry building with work on exterior

uses nonunion labor

12%

Visibility block is not covered 7%

Temperature Temperature is below 45o F 15%

Temperature Temperature is above 45o F 10%

Brick texture bricks are baked high

Weather is cold or moist

10%

Figure 9-8 A Hierarchical Estimation Framework for Masonry Construction

In addition to the problem of estimating the expected duration of an activity, some

scheduling procedures explicitly consider the uncertainty in activity duration

estimates by using the probabilistic distribution of activity durations. That is, the

duration of a particular activity is assu med to be a random variable that is distributed

in a particular fashion. For example, an activity duration might be assumed to be

distributed as a normal or a beta distributed random variable as illustrated in Figure 9-

9. This figure shows the probability or chance of experiencing a particular activity

duration based on a probabilistic distribution. The beta distribution is often used to

characterize activity durations, since it can have an absolute minimum and an absolute

maximum of possible duration times. The normal distribution is a good approximation

to the beta distribution in the center of the distribution and is easy to work with, so it

is often used as an approximation.

Figure 9-9 Beta and Normally Distributed Activity Durations

If a standard random variable is used to characterize the distribution of activity

durations, then only a few parameters are required to calculate the probability of any

particular duration. Still, the estimation problem is increased considerably since more

than one parameter is required to characterize most of the probabilistic distribution

used to represent activity durations. For the beta distribution, three or four parameters

are required depending on its generality, whereas the normal distribution requires two

parameters.

As an example, the normal distribution is characterized by two parameters, and

representing the average duration and the standard deviation of the duration,

respectively. Alternatively, the variance of the distribution could be used to

describe or characterize the variability of duration times; the variance is the value of

the standard deviation multiplied by itself. From historical data, these two parameters

can be estimated as:

(9.2)

(9.3)

where we assume that n different observations xk of the random variable x are

available. This estimation process might be applied to activity durations directly (so

that xk would be a record of an activity duration Dij on a past project) or to the

estimation of the distribution of productivities (so that xk would be a record of the

productivity in an activity Pi) on a past project) which, in turn, is used to estimate

durations using Equation (9.4). If more accuracy is desired, the estimation equations

for mean and standard deviation, Equations (9.2) and (9.3) would be used to estimate

the mean and standard deviation of the reciprocal of productivity to avoid non-linear

effects. Using estimates of productivities, the standard deviation of activity duration

would be calculated as:

(9.4)

where is the estimated standard deviation of the reciprocal of productivity that

is calculated from Equation (9.3) by substituting 1/P for x.

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9.6 Estimating Resource Requirements for Work Activities

In addition to precedence relationships and time durations, resource requirements are

usually estimated for each activity. Since the work activities defined for a project are

comprehensive, the total resources required for the project are the sum of the

resources required for the various activities. By making resource requirement

estimates for each activity, the requirements for particular resources during the course

of the project can be identified. Potential bottlenecks can thus be identified, and

schedule, resource allocation or technology changes made to avoid problems.

Many formal scheduling procedures can incorporate constraints imposed by the

availability of particular resources. For example, the unavailability of a specific piece

of equipment or crew may prohibit activities from being undertaken at a particular

time. Another type of resource is space. A planner typically will schedule only one

activity in the same location at the same time. While activities requiring the same

space may have no necessary technical precedence, simultaneous work might not be

possible. Computational procedures for these various scheduling problems will be

described in Chapters 10 and 11. In this section, we shall discuss the estimation of

required resources.

The initial problem in estimating resource requirements is to decide the extent and

number of resources that might be defined. At a very aggregate level, resources

categories might be limited to the amount of labor (measured in man-hours or in

dollars), the amount of materials required for an activity, and the total cost of the

activity. At this aggregate level, the resource estimates may be useful for purposes of

project monitoring and cash flow planning. For example, actual expenditures on an

activity can be compared with the estimated required resources to reveal any problems

that are being encountered during the course of a project. Monitoring procedures of

this sort are described in Chapter 12. However, this aggregate definition of resource

use would not reveal bottlenecks associated with particular types of equipment or

workers.

More detailed definitions of required resources would include the number and type of

both workers and equipment required by an activity as well as the amount and types

of materials. Standard resource requirements for particular activities can be recorded

and adjusted for the special conditions of particular projects. As a result, the resources

types required for particular activities may already be defined. Reliance on historical

or standard activity definitions of this type requires a standard coding system for

activities.

In making adjustments for the resources required by a particular activity, most of the

problems encountered in forming duration estimations described in the previous

section are also present. In particular, resources such as labor requirements will vary

in proportion to the work productivity, Pij, used to estimate activity durations in

Equation (9.1). Mathematically, a typical estimating equation would be:

(9.5)

where Rkij are the resources of type k required by activity ij, Dij is the duration of

activity ij, Nij is the number of standard crews allocated to activity ij, and Ukij is the

amount of resource type k used per standard crew. For example, if an activity required

eight hours with two crews assigned and each crew required three workers, the effort

would be R = 8*2*3 = 48 labor-hours.

From the planning perspective, the important decisions in estimating resource

requirements are to determine the type of technology and equipment to employ and

the number of crews to allocate to each task. Clearly, assigning additional crews

might result in faster completion of a particular activity. However, additional crews

might result in congestion and coordination problems, so that work productivity might

decline. Further, completing a particular activity earlier might not result in earlier

completion of the entire project, as discussed in Chapter 10.

Example 9-5: Resource Requirements for Block Foundations

In placing concrete block foundation walls, a typical crew would consist of three

bricklayers and two bricklayer helpers. If sufficient space was available on the site,

several crews could work on the same job at the same time, thereby speeding up

completion of the activity in proportion to the number of crews. In more restricted

sites, multiple crews might interfere with one another. For special considerations

such as complicated scaffolding or large blocks (such as twelve inch block), a

bricklayer helper for each bricklayer might be required to insure smooth and

productive work. In general, standard crew composition depends upon the specific

construction task and the equipment or technology employed. These standard crews

are then adjusted in response to special characteristics of a particular site.

Example 9-6: Pouring Concrete Slabs

For large concrete pours on horizontal slabs, it is important to plan the activity so

that the slab for a full block can be completed continuously in a single day. Resources

required for pouring the concrete depend upon the technology used. For example, a

standard crew for pumping concrete to the slab might include a foreman, five

laborers, one finisher, and one equipment operator. Related equipment would be

vibrators and the concrete pump itself. For delivering concrete with a chute directly

from the delivery truck, the standard crew might consist of a foreman, four laborers

and a finisher. The number of crews would be chosen to insure that the desired

amount of concrete could be placed in a single day. In addition to the resources

involved in the actual placement, it would also be necessary to insure a sufficient

number of delivery trucks and availability of the concrete itself.

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9.7 Coding Systems

One objective in many construction planning efforts is to define the plan within the

constraints of a universal coding system for identifying activities. Each activity

defined for a project would be identified by a pre-defined code specific to that

activity. The use of a common nomenclature or identification system is basically

motivated by the desire for better integration of organizational efforts and improved

information flow. In particular, coding systems are adopted to provide a numbering

system to replace verbal descriptions of items. These codes reduce the length or

complexity of the information to be recorded. A common coding system within an

organization also aids consistency in definitions and categories between projects and

among the various parties involved in a project. Common coding systems also aid in

the retrieval of historical records of cost, productivity and duration on particular

activities. Finally, electronic data storage and retrieval operations are much more

efficient with standard coding systems, as described in Chapter 14.

In North America, the most widely used standard coding system for constructed

facilities is the MASTERFORMAT system developed by the Construction

Specifications Institute (CSI) of the United States and Construction Specifications of

Canada. [10] After development of separate systems, this combined system was

originally introduced as the Uniform Construction Index (UCI) in 1972 and was

subsequently adopted for use by numerous firms, information providers, professional

societies and trade organizations. The term MASTERFORMAT was introduced with

the 1978 revision of the UCI codes. MASTERFORMAT provides a standard

identification code for nearly all the elements associated with building construction.

MASTERFORMAT involves a hierarchical coding system with multiple levels plus

keyword text descriptions of each item. In the numerical coding system, the first two

digits represent one of the sixteen divisions for work; a seventeenth division is used to

code conditions of the contract for a constructor. In the latest version of the

MASTERFORMAT, a third digit is added to indicate a subdivision within each

division. Each division is further specified by a three digit extension indicating

another level of subdivisions. In many cases, these subdivisions are further divided

with an additional three digits to identify more specific work items or materials. For

example, the code 16-950-960, "Electrical Equipment Testing" are defined as within

Division 16 (Electrical) and Sub-Division 950 (Testing). The keywords "Electrical

Equipment Testing" is a standard description of the activity. The seventeen major

divisions in the UCI/CSI MASTERFORMAT system are shown in Table 9-6. As an

example, site work second level divisions are shown in Table 9-7.

TABLE 9-6 Major Divisions in the Uniform Construction Index

0 Conditions of the contract

1 General requirements

2 Site work

3 Concrete

4 Masonry

5 Metals

6 Wood and plastics

7 Thermal and moisture prevention

8 Doors and windows

9 Finishes

10 Specialties

11 Equipment

12 Furnishings

13 Special construction

14 Conveying system

15 Mechanical

16 Electrical

While MASTERFORMAT provides a very useful means of organizing and

communicating information, it has some obvious limitations as a complete project

coding system. First, more specific information such as location of work or

responsible organization might be required for project cost control. Code extensions

are then added in addition to the digits in the basic MASTERFORMAT codes. For

example, a typical extended code might have the following elements:

0534.02220.21.A.00.cf34

The first four digits indicate the project for this activity; this code refers to an activity

on project number 0534. The next five digits refer to the MASTERFORMAT

secondary division; referring to Table 9-7, this activity would be 02220 "Excavating,

Backfilling and Compacting." The next two digits refer to specific activities defined

within this MASTERFORMAT code; the digits 21 in this example might refer to

excavation of column footings. The next character refers to the block or general area

on the site that the activity will take place; in this case, block A is indicated. The

digits 00 could be replaced by a code to indicate the responsible organization for the

activity. Finally, the characters cf34 refer to the particular design element number for

which this excavation is intended; in this case, column footing number 34 is intended.

Thus, this activity is to perform the excavation for column footing number 34 in block

A on the site. Note that a number of additional activities would be associated with

column footing 34, including formwork and concreting. Additional fields in the

coding systems might also be added to indicate the responsible crew for this activity

or to identify the specific location of the activity on the site (defined, for example, as

x, y and z coordinates with respect to a base point).

As a second problem, the MASTERFORMAT system was originally designed for

building construction activities, so it is difficult to include various construction

activities for other types of facilities or activities associated with planning or design.

Different coding systems have been provided by other organizations in particular sub-

fields such as power plants or roadways. Nevertheless, MASTERFORMAT provides

a useful starting point for organizing information in different construction domains.

In devising organizational codes for project activities, there is a continual tension

between adopting systems that are convenient or expedient for one project or for one

project manager and systems appropriate for an entire organization. As a general rule,

the record keeping and communication advantages of standard systems are excellent

arguments for their adoption. Even in small projects, however, ad hoc or haphazard

coding systems can lead to problems as the system is revised and extended over time.

TABLE 9-7 Secondary Divisions in MASTERFORMAT for Site Work [11]

02-010

02-012

Subsurface investigation

Standard penetration tests

02-350

02-355

Piles and caissons

Pile driving

02-016 Seismic investigation

02-050

02-060

02-070

02-075

02-080

Demolition

Building demolition

Selective demolition

Concrete removal

Asbestos removal

02-100

02-110

02-115

02-120

Site preparation

Site clearing

Selective clearing

Structure moving

02-140 Dewatering

02-150 Shoring and underpinning

02-160 Excavation supporting system

02-170 Cofferdams

02-200

02-210

02-220

02-230

02-240

02-250

02-270

02-280

02-290

Earthwork

Grading

Excavating, backfilling and compaction

Base course

Soil stabilization

Vibro-floatation

Slope protection

Soil treatment

Earth dams

02-300

02-305

02-310

02-320

02-330

02-340

Tunneling

Tunnel ventilation

Tunnel excavating

Tunnel lining

Tunnel grouting

Tunnel support systems

02-360

02-370

02-380

Driven piles

Bored/augered piles

Caissons

02-450 Railroad work

02-480 Marine work

02-500

02-510

02-515

02-525

02-530

02-540

02-545

02-550

02-560

02-575

02-580

Paving and surfacing

Walk, road and parking paving

Unit pavers

Curbs

Athletic paving and surfacing

Synthetic surfacing

Surfacing

Highway paving

Airfield paving

Pavement repair

Pavement marking

02-600 Piped utility materials

02-660 Water distribution

02-680 Fuel distribution

02-700 Sewage and drainage

02-760 Restoration of underground pipelines

02-770 Ponds and reservoirs

02-800 Power and communications

02-880 Site improvements

02-900 Landscaping

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9.8 References

1. Baracco-Miller, E., "Planning for Construction," Unpublished MS Thesis, Dept. of Civil Engineering, Carnegie Mellon University, 1987.

2. Construction Specifications Institute, MASTERFORMAT - Master List of Section Titles and Numbers, Releasing Industry Group, Alexandria, VA, 1983.

3. Jackson, M.J. Computers in Construction Planning and Control, Allen & Unwin, London, 1986.

4. Sacerdoti, E.D. A Structure for Plans and Behavior, Elsevier North-Holland, New York, 1977.

5. Zozaya-Gorostiza, C., "An Expert System for Construction Project Planning," Unpublished PhD Dissertation, Dept. of Civil Engineering, Carnegie Mellon University, 1988.

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9.9 Problems

1. Develop an alternative work breakdown for the activities shown in Figure 9-2 (Example 9-3). Begin first with a spatial division on the site (i.e. by roadway segment and structure number), and then include functional divisions to develop a different hierarchy of activities.

2. Consider a cold weather structure built by inflating a special rubber tent, spraying water on the tent, letting the water freeze, and then de-flating and removing the tent. Develop a work breakdown for this structure, precedence relationships, and estimate the required resources. Assume that the tent is twenty feet by fifteen feet by eight feet tall.

3. Develop a work breakdown and activity network for the project of designing a tower to support a radio transmission antenna.

4. Select a vacant site in your vicinity and define the various activities and precedences among these activities that would be required to prepare the site

for the placement of pre-fabricated residences. Use the coding system for site work shown in Table 9-7 for executing this problem.

5. Develop precedence relationships for the roadway project activities appearing in Figure 9-2 (Example 9-3).

6. Suppose that you have a robot capable of performing two tasks in manipulating blocks on a large tabletop:

o PLACE BLOCK X ON BLOCK Y: This action places the block x on top of the block y. Preconditions for applying this action are that both block x and block y have clear tops (so there is no block on top of x or y). The robot will automatically locate the specified blocks.

o CLEAR BLOCK X: This action removes any block from the top of block x. A necessary precondition for this action is that block x has one and only one block on top. The block removed is placed on the table top.

For this robot, answer the following questions:

3. Using only the two robot actions, specify a sequence of robot actions to take the five blocks shown in Figure 9-10(a) to the position shown in Figure 9-10(b) in five or six robot actions.

4. Specify a sequence of robot actions to move the blocks from position (b) to position (c) in Figure 9-10 in six moves.

5. Develop an activity network for the robot actions in moving from position (b) to position (c) in Figure 9-10. Prepare both activity-on-node and activity-on-link representations. Are there alternative sequences of activities that the robot might perform to accomplish the desired position?

Figure 9-10 Illustrative Block Positions for Robot Motion Planning

7. In the previous problem, suppose that switching from the PLACE BLOCK action to the CLEAR BLOCK action or vice versa requires an extra ten seconds. Movements themselves require 8 seconds. What is the sequence of actions of shortest duration to go from position (b) to position (a) in Figure 9-10?

8. Repeat Problem 6 above for the movement from position (a) to position (c) in Figure 9-10.

9. Repeat Problem 7 above for the movement from position (a) to position (c) in Figure 9-10.

10. Suppose that you have an enhanced robot with two additional commands capabilities:

o CARRY BLOCKS X-Y to BLOCK Z: This action moves blocks X-Y to the top of block Z. Blocks X-Y may involve any number of blocks as long as X is on the bottom and Y is on the top. This move assumes that Z has a clear top.

o CLEAR ALL BLOCK X TO BLOCK Z: This action moves all blocks on top of block X to the top of block Z. If a block Z is not specified, then the blocks are moved to the table top.

How do these capabilities change your answer to Problems 6 and 7?

11. How does the additional capability described in Problem 10 change your answer to Problems 8 and ?

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9.10 Footnotes

1. A.C. Doyle, "A Study in Scarlet," The Complete Sherlock Holmes, Doubleday &

Co., pg. 83, 1930. Back

2. See, for example, Paulson, B.C., S.A. Douglas, A. Kalk, A. Touran and G.A.

Victor, "Simulation and Analysis of Construction Operations," ASCE Journal of

Technical Topics in Civil Engineering, 109(2), August, 1983, pp. 89, or Carr, R.I.,

"Simulation of Construction Project Duration," ASCE Journal of the Construction

Division, 105(2), June 1979, 117-128. Back

3. For a description of a laser leveling system, see Paulson, B.C., Jr., "Automation and

Robotics for Construction," ASCE Journal of Construction Engineering and

Management, (111)3, pp. 190-207, Sept. 1985. Back

4. See Baker, K.R., Introduction to Sequencing and Scheduling, John-Wiley and Sons,

New York, 1974, for an introduction to scheduling in manufacturing. Back

5. See Skibniewski, M.J. and C.T. Hendrickson, "Evaluation Method for Robotics

Implementation: Application to Concrete Form Cleaning," Proc. Second Intl. Conf. on

Robotics in Construction, Carnegie-Mellon University, Pittsburgh, PA., 1985, for

more detail on the work process design of a concrete form cleaning robot. Back

6. This example is adapted from Aras, R. and J. Surkis, "PERT and CPM Techniques

in Project Management," ASCE Journal of the Construction Division, Vol. 90, No.

CO1, March, 1964. Back

7. For a discussion of network reachability and connectivity computational

algorithms, see Chapters 2 and 7 in N. Christofides, Graph Theory: An Algorithmic

Approach, London: Academic Press, 1975, or any other text on graph theory. Back

8. See H.R. Thomas, C.T. Matthews and J.G. Ward, "Learning Curve Models of

Construction Productivity," ASCE Journal of Construction Engineering and

Management, Vol. 112, No. 2, June 1986, pp. 245-258. Back

9. For a more extension discussion and description of this estimation procedure, see

Hendrickson, C., D. Martinelli, and D. Rehak, "Hierarchical Rule-based Activity

Duration Estimation," ASCE Journal of Construction Engineering and Management,

Vol 113, No. 2, 1987,pp. 288-301. Back

10. Information on the MASTERFORMAT coding system can be obtained from: The

Construction Specifications Institute, 601 Madison St., Alexandria VA 22314. Back

11. Source: MASTERFORMAT: Master List of Section Titles and Numbers, 1983 Edition, The construction Speculations Institute, Alexandria, VA, 1983. Back

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