integrated approach to overcome shortcomings in current delay analysis practices

Integrated Approach to Overcome Shortcomingsin Current Delay Analysis Practices

M. Talat Birgonul, Ph.D.1; Irem Dikmen, Ph.D.2; and Sinasi Bektas3

Abstract: Many factors, such as unforeseeable events, managerial and financial problems of contractors, insufficient technical capacity ofsite teams of contractors or Consultants, and so on, may lead to delays in construction projects. Proper analysis of compensability andquantum of a delay event is of prime importance. Any delay analysis application can be considered as a result of the combination of contractdocuments, scheduler, record-keeping mechanism at the site, communication among project participants, delay analyst, and delay analysismethodology. The main purposes of this study are to identify the shortcomings frequently encountered in the implementation of delay analy-sis applications in all stages of a construction project, to address the responsible element, and to propose a set of rules to overcome theseshortcomings and obtain accurate and reliable results. For this purpose, 17 shortcomings were identified. Moreover, an integrated approach isdeveloped which is composed of a set of rules solving all of the identified shortcomings, and a flowchart guiding the parties from scratch untilthe end of the project. This study is unique in its nature as it encompasses all stages of a construction project that contribute to a delay analysisapplication. DOI: 10.1061/(ASCE)CO.1943-7862.0000946. © 2014 American Society of Civil Engineers.

Author keywords: Construction delay; Delay analysis; Extension of time; Cost and schedule.

Introduction

Project delays are the most common and costly problem encoun-tered on construction projects. Analyzing construction delays hasbecome an integral part of a project’s construction life. Even withtoday’s technology and understanding of project management tech-niques, construction projects continue to suffer delays, and projectcompletion dates still get pushed back. There are many reasonswhy delays occur. They may be due to strikes, rework, poor organi-zation, material shortage, equipment failure, change orders, naturaldisasters, and so on. In addition, delays are often interconnected,making the situation even more complex (Alkass et al. 1996). Barry(2009) listed five commonly used delay analysis techniques:• Impacted as-planned method,• Time impact analysis (TIA) method,• Collapsed as-built method,• Snapshot/windows/time slice analysis method, and• As-planned versus as-built windows analysis method.

The time impact analysis is the most credible delay analysismethod among the five commonly used techniques. Time impactanalysis does not display the shortcomings of the other methods.This approach uses fragnets to analyze individual delay events. Theduration of delays and the relationship of delays to project activitiesare reviewed in detail with contemporaneous information. Thedelay is then inserted into the project. This process provides both

parties with an opportunity to scrutinize the delay and reducedisputes (Arditi and Pattanakitchamroon 2006).

Recent Developments in Delay Analysis

Quite a few researchers began to focus their attention on findingsolutions to existing shortcomings of delay analysis techniques.A number of solution methods and delay analysis techniques wereproposed. In the following sections, the most controversial short-comings of delay analysis techniques and proposed partial solu-tions will be discussed.

Float Ownership

In the critical path method, total float or slack is defined as the totalamount of time that an activity can be delayed without delaying theproject’s completion date. Because float is a critical asset, the ques-tion of who owns float has increasingly concerned contractualparties. The result of schedule delay analysis can be affected bythe various views regarding who owns float (Arditi and Pattana-kitchamroon 2006). Consequently, float ownership and its usecan be a major source of dispute when the project suffers fromdelay (Prateapusanond 2003).

Many researchers proposed apportionment methods of float, tobe adopted by the parties to a project. Sakka and El-Sayegh (2007)quantify the impact of float loss on project schedule and cost. De laGarza et al. (1991) suggest that the contractor owns float but has totrade it on demand by the owner, whereas Zack (1993) recommendsthe use of a joint ownership of float. Gong (1997) created the safefloat concept, which can be used without severely affecting the riskof project delay. Householder and Rutland (1990) propose a differ-ent approach that entitles the party who loses or gains as a result offluctuation in the project cost to own and use float. Pasiphol andPopescu (1994) allocate total float to individual activities to solvethe float ownership problem. Al-Gahtani and Mohan (2007) pro-pose a different total-float apportionment method. According totheir method, if a party is responsible for a delay event which

1Professor, Dept. of Civil Engineering, Middle East Technical Univ.,Ankara, Turkey. E-mail: [email protected]

2Professor, Dept. of Civil Engineering, Middle East Technical Univ.,Ankara, Turkey. E-mail: [email protected]

3Civil Engineer, PM Consultancy, Ankara, Turkey (correspondingauthor). E-mail: [email protected]

Note. This manuscript was submitted on May 30, 2014; approved onOctober 10, 2014; published online on November 17, 2014. Discussionperiod open until April 17, 2015; separate discussions must be submittedfor individual papers. This paper is part of the Journal of ConstructionEngineering and Management, © ASCE, ISSN 0733-9364/04014088(11)/$25.00.

© ASCE 04014088-1 J. Constr. Eng. Manage.

J. Constr. Eng. Manage.

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http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000946




consumes the total float to some degree, the responsible party willbe discredited to the affected activity. Prateapusanond (2003) pro-poses that each party owns half of the total float available on anyactivity, which is an equitable method to some extent and easilyaccepted by the construction industry. Ibbs and Nguyen (2008)propose a technique which sets rules to be followed by the delayanalyst with regard to ownership of float. According to this method,total float is shared, based on the agreed basis. If the total float isincreased or decreased as a result of acceleration or delay,the responsible party’s total float of the corresponding activity isincreased or decreased accordingly.

Concurrent Delay

Concurrent delays occur frequently, particularly at the peak of aproject when multiple-responsibility activities are being performedsimultaneously (Baram 2000). Analysis of schedule delays takes amajor leap in complexity when there are multiple sources of delaywith interrelated impacts (Galloway and Nielsen 1990; Kutil andNess 1997). Concurrent delay is customarily described as two ormore delays that occur at the same time, either of which would causea project delay. If either of them had not occurred, the project sched-ule would have been delayed by the other (Stumpf 2000). Even themost reliable delay analysis techniques, including time impact analy-sis, are not capable of handling concurrent delays. Recently, research-ers proposed new techniques such as the delay analysis method usingdelay section (DAMUDS) and daily windows delay analysis.

Kim et al. (2005) proposed the delay analysis method usingdelay section. Two inadequacies in existing methods of scheduledelay analysis were identified:1. Ambiguity in the analysis of concurrent delay, and2. Inadequate consideration of time-shortened activities.To overcome the shortcomings of the existing methods, which

are the ambiguity of concurrent delay analysis and inadequateconsideration for time-shortened activities, two core concepts aresuggested here:• Delay section (DS) and• Contractor’s float (CF).

The DS is defined as a discrete and meaningful delay analysistime increment for dividing the delay-occurred duration into a sin-gle delay-occurred period (not overlapped) and two or more delays-occurred periods (overlapped) (Kim et al. 2005). This treatmentmakes the analysis unit discrete and meaningful. CF representsthe effort of a contractor to shorten the time of activities, thus reduc-ing the total project duration (Kim et al. 2005). The delay analysisprocedure of DAMUDS is based on DS, CF, and the analyticalapproach of traditional windows analysis (TWA). The DAMUDSmethod calculates the delay impact by three discrete streams: nodelay, a single portion of delay or a single delay, and two or moreportions of delay on the analysis section.

Hegazy and Zhang (2005) proposed the daily windows delayanalysis method (DWDA). DWDA requires the analyst to updatethe project on a daily basis, which can be criticized for beingimpractical even though concurrency problems can be cured byproper implementation of this method.

The Society of Construction Law (SCL) Delay and DisruptionProtocol sets valuable rules for concurrency as it relates to cost andextension of time.

The SCL (2002) Delay and Disruption Protocol defines concur-rency as follows: true concurrent delay is the occurrence of two ormore delay events at the same time, one an employer risk event, theother a contractor risk event, and the effects of which are felt atthe same time. The term concurrent delay is often used to describe

the situation in which two or more delay events arise at differenttimes, but the effects of which are felt (in whole or in part) at thesame time. To avoid confusion, this is more correctly termed theconcurrent effect of sequential delay events.

The SCL (2002) Delay and Disruption Protocol further discussesthe issue of concurrency in relation to extensions of time as follows.Where contractor delay in completion occurs concurrently withemployer delay in completion, the contractor’s concurrent delayshould not reduce any extension of time (EOT) due. Where employerrisk events and contractor risk events occur sequentially but haveconcurrent effects, here again, any contractor delay should not reducethe amount of EOT due to the contractor as a result of the employerdelay. If the contractor incurs additional costs that are caused both byemployer delay and contractor delay, then the contractor should onlyrecover compensation if it is possible to separate the additional costscaused by the employer delay from those caused by the contractordelay. In most cases, this will mean that the contractor will be entitledto compensation only for any period in which the employer delayexceeds the duration of the contractor delay.

Loss of Productivity

Productivity is commonly defined as the quantity of work pro-duced, or work output (e.g., linear feet of pipe), per unit of inputor effort (e.g., dollars or work hours). Productivity measurementis typically expressed as a ratio or as a percentage. Other measure-ment schemes may use a production rate such as the amount ofwork that may be accomplished in a given amount of time(e.g., 200 m3 of concrete placed per day) (Klanac and Nelson2004). For example, if it is assumed that a factory, working withone concrete batch plant, is producing 1,000 m3 of concrete perday, then the factory’s production rate is 1,000 m3=day, whereasits productivity is 1,000 m3=batch plant. If the factory’s capacityis increased by purchasing an additional batch plant, the factory’sproduction rate increases to 2,000 m3=day, whereas productivity ofbatch plant remains the same.

Lee and Diekmann (2011) proposed a delay analysis techniqueconsidering production rate. The central idea of their modifiedmethod is to incorporate the varying rate of production into thedelay analysis process. Using the learning curve effect, the produc-tion rate is divided into three subphases of performance: learningrate, production rate, and three subphases of performance; a modi-fied method for delay analysis, DAP (delay analysis consideringproduction rate), is proposed.

Resource Overallocation

The need for reflecting and capturing the practice of resourceallocation in schedule analysis is apparent and imperative. Manyexisting and new techniques pay little attention to this critical issue(Ibbs and Nguyen 2007).

Ibbs and Nguyen (2007) used window analysis to show theeffects of resource allocation in delay analysis. Enhanced windowanalysis considering resource allocation includes additional stepscompared to the current window analysis. Seven steps of currentwindow analysis are adopted from Stumpf (2000). Basically, steps2, 3, 5, and 6 between current and enhanced window analyses aresimilar. The enhanced window analysis introduces step 0, whichemphasizes that technical and resource constraints and resourceavailability and allocation practice should be documented and dis-seminated, and a consensus should be obtained between the con-tractor and owner. This ensures that schedule analysis, consideringthe effects of resource allocation, is legally enforceable thereafter.



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For instance, the contractor must inform the owner at the beginningthat he or she will only be able to allocate two backhoes on the site.Resource allocation practices can change and/or be changed overtime when more information from the project or project parties isavailable. This is reflected in step 7, which includes updating step 0and repeats the procedure from steps 2–6 for each window period tothe end of the project (Ibbs and Nguyen 2007).

Rework

Rework is a serious problem facing large and complex constructionprojects, particularly industrial projects that involve multiple par-ties such as contractors, suppliers, and trades. In such a complexenvironment, where many activities by many parties take placesimultaneously, errors, omissions, and misunderstandings oftencause undesirable outcomes that have to be reworked. Rework,thus, has been defined as the effort of redoing a process or activitythat was incorrectly implemented the first time (Love and Li 2000).

Various researchers have studied rework from different perspec-tives such as the rework cycle, root causes, and impact on projectperformance (Love et al. 2010). Cooper (1993) introduced the con-cept of the rework cycle in projects, where the rework itself is notdone properly, thus requiring further rework in a recursive cyclethat can extend project duration far beyond what was originallyconceived. This concept becomes important to the understandingof the interactions among various project factors including rework,which can be studied using system dynamics tools (Lyneis andFord 2007). With respect to root causes, several studies and surveyswere conducted to identify and classify the root causes of rework.Almost all studies reported that rework plays a major role in costand schedule overruns (Hegazy et al. 2011).

Hegazy et al. (2011) proposed a technique called delay analysisconsidering rework, which modified the daily windows analysis toaccommodate the representation and analysis of rework events aswell as the consideration of resource overallocation in delay analysis.

Acceleration

Thomas (2000) described acceleration as having more work to per-form in the same period of time, or having a shorter period of timeto perform the same amount of work.

The windows analysis has no mechanism for taking into accounttime-shortened activities that reduce the total project duration.Hegazy and Zhang (2005) proposed a new approach for represent-ing and analyzing acceleration in windows analysis. This approachuses daily windows and deals with acceleration as a negative delay,attributable to the party who creates it. In another effort, Kim et al.(2005) introduced a new concept called contractor’s float to solvethe problem of handling time-shortened activities that contributeto a reduction in the total duration of the project. When the totalproject duration is reduced by time-shortened activities becauseof the contractor’s efforts, the time reduced could be utilized by thecontractor as a safety margin against future delays (Hegazy andMenesi 2008).

Integrated Approach

Even though the aforementioned researchers have studied a numberof shortcomings of delay analysis practices, none of them focusedon all of the shortcomings, including those• arising out of contract documents,• originating from the scheduler,• resulting from lack of record keeping and efficient

communication,• growing out of the incapability of delay analysis technique, and• caused by the delay analyst.

Researchers have mostly focused on the shortcomings arisingout of the incapability of delay analysis techniques; in fact, eventhe researchers did not address all of the above mentioned short-comings in one study. It is apparent that, in practice, there are lots ofstages in the construction process, yet to implement an efficientdelay analysis application, it is crucial to identify the problems ineach stage.

The main objectives of this research are to identify frequentlyencountered shortcomings of delay analysis applications in allstages of a construction project, address the responsible element,and propose a set of rules to overcome these shortcomings andobtain accurate and reliable results.

For this purpose, identified shortcomings are listed in Table 1together with the responsible element(s). Some of the shortcomingswere resolved by SCL Delay and Disruption Protocol’s principles,which are widely accepted by the construction industry, such as

Table 1. Identified Shortcomings of Delay Analysis Applications and Major Causes

Numbers DescriptionContractdocuments Scheduler

Delayanalyst

Delay analysistechnique

Record keepingand communication

1 Unreasonable productivity estimation — — O — —2 Loss of productivity — — O — —3 Float ownership O — — — —4 Critical path changes — — — O —5 Concurrent delay — — — O —6 Nonworking days — O — — —7 Net and concurrent effect — O — — —8 Introduction of a new work item — — — — O9 Omission of an existing work item — — — O O10 Pacing delay — — O — —11 Resource overallocation — O O — —12 Rework — — — — O13 Acceleration — — — O O14 Mitigation — — — O O15 Increase in quantity of a work item — — — — O16 Decrease in quantity of a work item — — — O O17 Change in sequence of activities — — — — O

Note: O = shortcoming applies.



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liability analysis in concurrent delays. Therefore, they are notincluded in the list and are adopted directly in the analysis.

An integrated approach was created to overcome all of the iden-tified shortcomings. In this approach, a set of rules was prepared asshown in Table 2. Moreover, a flowchart was prepared (as shownin Fig. 1), which demonstrates the process of the integrated ap-proach’s rules. As shown in Table 2, all of the shortcomings wereaccounted for in one or two rules of the integrated approach. Theserules guide the parties to a contract from scratch until the end ofthe performance period. Rule 1 solves the float ownership problemby requiring the parties to define the ownership of the float andincorporate it into the contract documents. Rules 2 and 3 guide thescheduler to identify the nonworking days and prepare a resource-loaded schedule to be able to identify resource overallocations and

net effects of delay events during the course of the project. Rules4–7 require a proper record-keeping system and efficient commu-nication among project participants. Rule 8 represents the coreprinciple of time impact analysis which accounts for changes incritical paths during the course of the project. Rule 9 guides thedelay analyst to check whether a noncritical activity is assigneda critical resource to identify resource overallocations. Rule 10 con-siders advancements (negative delays) such as mitigation, acceler-ation, or decrease in quantities of activities, and requires the delayanalyst to change the activity durations accordingly or omit activ-ities when necessary. Rule 11 is another core principle of the timeimpact analysis which necessitates the delay analyst to reflect theeffect of delay events in the schedule by adding fragnets or in-creasing activity durations. Rule 12 deals with productivity issues,

Table 2. Integrated Approach’s Rules

Rule Corrected shortcoming Description

1 Float ownership Apportionment method of the project float will be included in the contract documents to avoid debate withregard to ownership of the float between the parties in the course of the project. Any party may own the floator they share as agreed

2 Resource overallocation An activity that is off the critical path may suffer delay. Such activities may possibly be critical in terms ofavailability of resources. Construction schedule will be resource loaded to be able to determine suchactivities and identify resource overallocations resulting from delays in noncritical activities

3 Nonworking days netand concurrent effect

Quantum of delay or advancement is determined in terms of working days. Therefore, nonworking daysincluding religious, weekend or national holidays, and special days in the country the project is beingundertaken will be identified in the construction schedule, in order to calculate the net impact of an eventcorrectly

4 Change in sequence In the course of any construction project, management team may change the construction methodology andhence change the sequence of the works in the as-planned section of the construction schedule uponagreement between parties to the project. Delay analyst will be informed with regard to such changes

5 Rework By their very nature, most construction work items are prone to error. Therefore, rework is inevitable inlarge-scale construction projects due to erroneous applications. Because reworks in large-scale projects canbe easily overlooked, it is important to properly record such items. These records will be conveyed to thedelay analyst properly

6 Increase in quantity Variation order (change order) is a common occurrence in all types of construction projects. This can occurthrough a variety of ways including increase or decrease in quantities of work items (change in quantity),introduction of a new work item, or omission of an existing work item (change in scope). Such changes willbe recorded and conveyed to the delay analyst

Decrease in quantityIntroduction of itemsOmission of items

7 Acceleration Many construction contracts together with SCL Delay and Disruption Protocol necessitate the contractor torecover all types of delays by way of mitigation and excusable delays by way of acceleration when orderedby the other party to do so. This kind of action will be recorded and conveyed to the delay analyst

Mitigation

8 Changes in critical path Delay analyst will update the construction schedule as of the start date of the event giving rise to delayanalysis application. After the updating process, the delay analyst will identify the critical path and willcheck whether the event affects the critical path

9 Resource overallocation If the event does not affect the critical path, the delay analyst will check whether the work item which isaffected by the event is assigned a critical resource or not. If so, the critical activities that become concurrentafter incorporation of the event will be examined to determine whether they are impacted in terms ofresource overallocation. If it does not affect such an activity, net impact to affected activity will be recorded

10 Acceleration If the event is the kind which results in a decreased time for completion such as acceleration, mitigation,decrease in quantity of a work item, or omission of an existing work item, the delay analyst will decrease theduration of the impacted activity or simply remove it when necessary

MitigationDecrease in quantity omission

11 Increase in quantity If the event is a kind of delay event that extends the completion date of the project, the delay analyst willincrease the duration of the impacted activity or add a fragnet activity when necessaryIntroduction of items

12 Loss of productivity Delay analyst will determine the liability of the delay event taking account of risk responsibilities and floatapportionment method defined in the contract documents. Lost productivity of contractor due to the otherparty’s actions or inactions and unreasonable productivity estimations of the contractor during preparationof the schedule will not be left out in determination of responsibility

Unreasonable productivity estimationFloat ownership

13 Concurrent delay Delay analyst will check whether a concurrent delay in a parallel critical path starts simultaneously orwhether another delay event occurs on the same path between start and finish dates of the delay event inquestion. If so, liability analysis of the concurrent delay event will be performed as is in Rule 12 andconcurrency rules of SCL will be performed for the concurrent portion provided that concurrent delay is nota result of deliberate slow down

Pacing delayConcurrent effect

14 — Net impact of the event will be calculated based on the liability analysis. Rules 4–14 will be performed foreach of the events encountered in the course of the project

15 — Aggregate impact of all events will be calculated based on the liability analysis performed before for eachparty. Mitigation and acceleration may be deducted from the employer-culpable delay events based on thecircumstances and against compensation, respectively



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including lost productivity as a result of actions or inactions of theemployer and unreasonable (generally overoptimistic) productivityestimations. Rule 13 guides the delay analyst to account for con-current delays.

Finally, rules 14 and 15 require the application of liability analy-sis principles of the SCL Delay and Disruption Protocol to calculatethe net impact of events for each of the parties. Because mitigationis considered the inherent responsibility of the contractor by the

Delay Analysis Stage

Construc�on Stage

Planning & Programming Stage

Contract Agreement Stage

Scru�nize the Contract Documents

Is appor�onment method of the project

float defined in the Contract Documents?

Add the appor�onment method of float in the Contract

Documents

Load cri�cal resources into Construc�on

Schedule

Is the Construc�on Schedule resource

loaded?

Are the non-working days defined in the

Construc�on Schedule?

Define non-working days by crea�ng various

calendars and assign them to relevant

ac�vi�es

Is there any planned change in construc�on method within the as-

planned por�on?

Change the sequence of the work items in the as-planned por�on and revise the comple�on date

Keep records of all delaying or advancing events including rework, increase or decrease in quan��es of work items, added or omi�ed work items, accelera�on and mi�ga�on

Convey the records to delay analyst

Update the project as of the start date of the event and

iden�fy the cri�cal path

Does the event affect the cri�cal

path?

Does the event extend the �me for comple�on?

Does the event affect an ac�vity which is on

cri�cal path in terms of resource usage?

If an ac�vity which is not on the cri�cal path is delayed due to resource constraint,

record this event for possible future use.

Comple�on date is not affected by the event

Increase the dura�on of affected work items, add

fragnets or slip start dates when necessary

Decrease the dura�on of affected ac�vity or omit

where necessary and revise comple�on date

Determine liability of event considering the float appor�onment

method and lost produc�vity or op�mis�c produc�vity es�ma�ons

Is there another delay event occuring concurrently or

affec�ng the comple�on date concurrently?

Is the concurrent delay a result of a deliberate slow down in concurrent work

items in order not to hurry up and wait

Determine liability of concurrent event considering the float

appor�onment method and lost produc�vity or op�mis�c produc�vity es�ma�ons

Apply concurrency rules to determine liability of concurrent por�on

Net impact of event on project dura�on

Repeat the steps in Construc�on Stage and Delay Analysis Stage for all

events

Net impact of all events to project dura�on for each party as of data

date

YES

NO

NO

YES

YES

NO

YES

NO

NO

YES NO

YESNO

YES

NO

YES

YES NO

RULE 1

RULE 2

RULE 3

RULE 4

RULES 5-7

RULE 8

RULE 9

RULE 10

RULE 11

RULE 12

RULE 13

RULE 14

RULE 15

Fig. 1. Integrated approach flowchart



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SCL Delay and Disruption Protocol, it may be deducted fromemployer-culpable delay events according to circumstance. If thecontractor is ordered to accelerate the work, accelerated days canbe deducted from employer-culpable delay events against compen-sation. Rules of the integrated approach will be applied in thefollowing case study.

Case Study

The as-planned schedule of a simple project with six activities isshown in Fig. 2. Because the contractor developed the constructionschedule, and float is an integral part of it, pursuant to the integratedapproach’s Rule 1, the parties agreed that the contractor owns thefloat. However, the employer may freely use the float of a path, aslong as the remaining float amount is more than or equal to the totalcontractor-culpable delay events on the same path. If the comple-tion date of the project is delayed as a result of a combination ofboth the employer’s and contractor’s usage of the total float of thesame path, the delay event will be treated as if it is an employer-culpable delay event. Nonworking days were identified by thescheduler as required by rule 3. Activities A–C and D–F are

assigned 2 and 1 nonworking days, respectively. According torule 2, activities B and E are assigned major resources.

The contractor has only one unit of resource 1 assigned to thisproject. All changes in scope of the project, including additionalactivities, omissions, or decrease or increase in quantities of activ-ities, will be the responsibility of the employer. Parties have agreedto apply the SCL Delay and Disruption Protocol’s principles incontroversial situations such as liability analysis in concurrent de-lays and mitigation. The description of events encountered by thecontractor in the course of the case study is summarized togetherwith relevant shortcoming(s) and the integrated approach’s rule(s)in Table 3. Detailed analysis of events will be performed under thefollowing subheadings together with updated schedules.

Analysis of Delay Events

Day 5: Two Days Employer-Culpable and 1 DayContractor-Culpable DelayIn the baseline schedule, the duration of Activity Awas determinedaccording to quantities specified in tender documents and produc-tion rate estimations from the contractor. In tender documents, the

TF 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

3 daysResource 1

3 days

0 day

0 dayResource 1

0 day

Non-working Day EC IE EN

A

Activity

B

C

D

3 days

E

F

Fig. 2. As-planned schedule

Table 3. Description of Events Together with Relevant Shortcomings and Rules

Day Relevant shortcoming(s)Applicablerule(s) Description

4,5 Increase in quantity 6 Employer issued a variation order increasing the duration of Activity A from 3 to 5 days5 Unreasonable

productivity estimations12 One-day delay event is originated from overoptimistic productivity estimation of contractor’s

engineers6 Mitigation 7,10 Contractor decided to mitigate 1-day delay suffered on day 5 and employer issued a variation

order adding a new activity which was not included in the original scope of worksIntroduction of anactivity

6

7 Rework 5 Employer commented that the work does not satisfy the requirements of standard technicalspecifications and must be repeated on day 7. Activity B affects Activity E in terms ofresource overallocation. Even though the delay suffered on Activity B is inexcusable,responsibility is passed to employer because contractor owns the float

Resource overallocation 2,9Float ownership 1,12

9 Acceleration 7,10 Contractor finished Activity B on ninth day by doubling performance10 Changes in critical path 8 After 1-day delay, it was realized that the path on which Activity C takes part became critical.

Moreover, actual quantity of Activity G turned out to be half of the presumed quantityDecrease in quantity 611 Concurrent delay 13 One-day contractor-culpable delay and one-day employer-culpable delay (delay due to lost

productivity) occurred concurrently. It was realized that pacing delay is not applicable in thissituation. SCL principles were applied in liability analysis

Pacing delay 13Loss of productivity 12

12 Net effect 3 Contractor could not start work on Activity E. Even though duration of Activity E is increasedby 1 day, net effect of this delay event turned out to be 2 days due to nonworking daysassigned to this activity. After that, contractor decided to change the sequence in theas-planned section to recover this delay

Nonworking days 3Change in sequence 4

14–16 Concurrent effect 3,13 One-day contractor-culpable delay and 2 days third-party-culpable delay occurred. The neteffect was 3 days for each due to nonworking days assigned to impacted activities. Therefore,the concurrent effect is 3 days. SCL principles were applied in liability analysis

Omission of an activity 6,10



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total quantity of Activity A was 15 units. However, the employerissued a variation order increasing the quantity by 66% from 15to 25 units. Pursuant to Rule 6, the delay analyst is informed withregard to this increment. The contractor’s production rate is5 units=day. Therefore, according to Rule 9, revised duration is cal-culated by the delay analyst to be 5 days, extending the activityduration by 2 days as shown in Fig. 3. As the parties agreed thatsuch scope changes are the responsibility of the employer, thisdelay event is recorded as an employer-culpable delay event. How-ever, it did not extend the completion date of the project, but con-sumed 2 days out of the 3 days total float of Activity A.

On day 5, a 1-day delaying event occurred concurrently onActivity D. Because this activity is on the critical path, the projectcompletion date is extended by 1 day. This delay event originatedfrom overoptimistic productivity estimation by the contractor’sengineers. Therefore, it is attributable to the contractor. The produc-tivity estimate for Activity D was 10 units per day. However, inthe first 4 days, 9 units per day could be accomplished. Therefore,following Rules 11–14, Activity D is extended by 1 day as shownin Fig. 3, and a 1-day inexcusable delay event is recorded.

Day 6: One-Day Mitigation by the ContractorOn day 6, the contractor decided to mitigate the 1-day delay suf-fered on day 5. For this purpose, a better management strategy wasadopted, and productivity was increased by 100% on day 6 from 10to 20 units per day, decreasing the activity duration by 1 day. Thisaction was conveyed to the delay analyst by responsible personnelpursuant to Rule 7, and the duration of Activity D was decreased by

1 day by the delay analyst according to Rule 10, as shown in Fig. 4.Moreover, the employer issued a variation order adding a newactivity which was not included in the original scope of the work.According to Rule 6, this information was conveyed to the delayanalyst. Following Rule 9, it was noted that this delay event did notaffect time for completion.

Day 7: One-Day Contractor Culpable DelayOn day 7, the contractor suffered a delay as a result of defectivework in Activity B. The employer commented that this work didnot satisfy the requirements of standard technical specifications,which is why it would not be accepted. According to Rule 5, thesite team informed the delay analyst about this issue, and it wasreflected in the construction schedule as shown in Fig. 5. It is ap-parent that the delay analyst considered the situation as rework andinserted a 1-day delay into Activity B. Even though Activity B is noton the critical path, following Rule 9, it was acknowledged thatActivity B affected Activity E in terms of resource overallocation.As the contractor had only one unit of resource 1, Activity B andActivity E, which use resource 1, could not be performed concur-rently, and thus, pursuant to Rules 11–14, Activity E was delayedby 1 day, which was on the critical path, as shown in Fig. 5.

To perform the liability analysis, it was considered that theemployer had consumed 2 days float on this path with a 2-daydelay on Activity A which could otherwise have been used by thecontractor. As the parties agreed upon the contractor’s ownershipof the float, liability of this delay was passed from contractor toemployer and recorded as 1-day employer-culpable delay.

TF 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

2 daysResource 1

2 days

0 day

0 dayResource 1

0 day


Activity

A -

B

C

D

E

F

Fig. 3. Updated schedule—data date: day 5


TF 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

1 dayResource 1

1 day

0 day

0 dayResource 1

0 day

2 days

C

D

E

F

Activity

A -

B

G




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Day 9: Acceleration by the Contractor againstCompensationOn day 9, the employer requested the contractor to recover the1-day delay by accelerating the works. The contractor decidedto work a double shift on Activity B. It was planned to execute5 units=day. By working a double shift, the contractor succeededin finishing Activity B on the ninth day by doubling performance.The delay analyst was informed accordingly about the accelerationprocess pursuant to Rule 8. The delay analyst decreased the dura-tion of the affected activity following Rule 10, as shown in Fig. 6.It was recorded that the performance period was decreased by 1 dayas a result of the contractor’s acceleration against compensation.

Day 10: One-Day Third-Party DelayThe contractor suffered a 1-day delay due to delays in customsclearance of necessary items to perform Activity C. Accordingto the contract documents, delays in country authorities are con-sidered as third-party delay events. The delay analyst updated theconstruction schedule at the start date of the delay event pursuantto Rule 8. Following Rules 11–14, the duration of Activity C wasincreased by 1 day. It was realized that the path on which Activity Ctakes place became critical. However, this delay event did notextend the completion date of the project.

Moreover, on day 10, it was realized that the actual quantityof Activity G turned out to be half of the presumed quantity.

Therefore, following Rule 6, the delay analyst was informedaccordingly. After that, the delay analyst, according to Rule 10,decreased the duration as shown in Fig. 7. However, as Activity Gis not on the critical path, it did not impact the completion date ofthe project.

Day 11: One-Day Contractor-Culpable Delay Concurrentwith 1-Day Employer-Culpable DelayThe contractor suffered a 1-day delay due to lost productivity re-sulting from intermittent working on Activity E. The contractorplanned to perform 7 units per day on Activity E. However, thecontractor could accomplish 0.01 unit of work on the 11th day dueto intermittent working caused by the employer’s site personnel.Therefore, pursuant to Rules 11–14, the delay analyst increasedthe duration of Activity E by 1 day. Concurrently, the contractorfailed to organize the necessary crew to accomplish Activity C. Pur-suant to Rules 11–14, the delay analyst increased the duration ofActivity C by 1 day. To perform the liability analysis, Rule 13 wasapplied by the delay analyst, and it was realized that pacing delaywas not applicable, and the contractor would be awarded 1 dayEOT, as shown in Fig. 8, but no compensation in terms of cost.

Day 12: One-Day Contractor-Culpable DelayOn day 12, the contractor could not start work on Activity E due tothe resignation of a responsible chief from execution of Activity E.

TF 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

1 dayResource 1

1 day

1 day

0 dayResource 1

0 day

3 days


G

B

C

D

E

F

Activity

A -


TF 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

-Resource 1

1 day

-

0 dayResource 1

0 day

2 days


-

B

C

D

E

F

G

Activity

A




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Rules 11–14 were followed as shown in Fig. 9. Because Activity Eis on the critical path, it did affect the completion date of theproject. Even though the duration of Activity E was increasedby 1 day, the net effect of this delay event turned out to be 2 days,due to nonworking days assigned to this activity. As soon as thecontractor realized this delay, the decision was made to changethe sequence of activities in the as-planned section. Therefore,

following Rule 4, the delay analyst changed the sequence in theas-planned section as shown in Fig. 10.

Day 16: One-Day Employer and 2 DaysThird-Party-Culpable DelayOn day 14, the contractor suffered a 1-day delay due to lateinstructions from the employer’s engineer to perform Activity C.


TF 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

-Resource 1

0 day

-

0 dayResource 1

0 day

-G

C

D

E

F

Activity

A -

B


TF 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

-Resource 1

0 day

-

0 dayResource 1

0 day

-


C

D

E

F

G

Activity

A

B

-


TF 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

-Resource 1

0 day

-

0 dayResource 1

0 day

-


G

C

D

E

F

Activity

A -

B




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Concurrently, Activity E could not be performed as a result of adelay in approval of the work permit of key personnel requiredon site to execute the remaining portion thereof. These delayingevents were incorporated into the schedule as required by Rules11–14. Due to different nonworking days of two concurrent delayevents, the net effects thereof were 3 days and concurrent. Accord-ing to Rule 13, the concurrency principles of the SCL Delay andDisruption Protocol were applied. Two delaying events had thesame effect; therefore, their concurrent effect is 3 days. Accordingto the SCL principles, when third-party-culpable and employer-culpable delay events are concurrent, or their effects are concur-rent, then the contractor is granted EOT but not costs. Therefore,the contractor was granted 3 calendar days EOT without mone-tary compensation. Moreover, Activity F was cancelled by the

employer. This omission was conveyed to the delay analyst pur-suant to Rule 6. After that, the delay analyst applied Rule 10 andomitted Activity F as shown in Fig. 11. Table 4 summarizes theresults of the proposed Integrated Approach.

Conclusion

The integrated approach brings a new perspective to delay analysisapplications. It considers all contributing stages of an applicationand proposes practical solutions to all shortcomings encountered ateach stage. As a real-time analysis, the integrated approach gathersall useful aspects of previous researches. All of the shortcomingsencountered by the project participants can be managed by follow-ing the straightforward flowchart of the integrated approach. Itguides the user from scratch until the end of the performanceperiod.

Float ownership, which is one of the controversial issues, isresolved by requiring the project participants to insert a term withregard to apportionment of the float. As such, an agreed apportion-ment method, inherently, will not be challenged by the parties inthe course of the project. For some of the problems, such as deter-mination of liability in concurrent situations, core principles widelyaccepted by the industry are applied, in this case the SCL Delayand Disruption Protocol. Integrated approach adopts some ofTIA’s rules, including requiring up-to-date schedules just before thedelay event takes place and adding fragnets representing the delayevents. Integrated approach accounts for recovery events such as

TF 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

-Resource 1

0 day

-

0 dayResource 1

0 day

-


Activity

A -

B

C

D

E

F

G



TF 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

-Resource 1

0 day

-

0 dayResource 1

-

-

B

C

D

E

G

Activity

A


Table 4. Results of Integrated Approach

Day EC EN IEConcurrentportion

Recovery(EC)

Recovery(EN)

Recovery(IE)

5 — — 1 — — — —6 — — — — — — (1)7 1 — — — — — —9 — — — — (1) — —11 1 1 — 1 — — —12 — — 1 — — — (1)16 3 3 — 3 — — —Total 5 4 2 4 (1) — (2)



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mitigation, acceleration, or scope changes. Moreover, it handlesconcurrency by proposing a set of rules in concurrent situations.

In sum, the integrated approach defines required rules for a re-liable and accurate analysis, and demonstrates through its flowchartthat its rules are applicable. Resolving main shortcomings of delayanalysis practices, when properly applied, integrated approach is avaluable and useful tool for practitioners.

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