time management 641 topic 03 activity sequencing

TIME MANAGEMENT 641

Topic 03

Activity Sequencing

• Assemble project scope, historical data, WBS

and identify constraints & assumptions;

• Create an Activity List, document supporting

detail and update WBS;

SUMMARY TO DATE

TIME MANAGEMENT PROCESS

• Definition of activities;

• Sequencing of activities;

• Estimating duration of activities;

• Schedule development;

• Monitor and control of schedule;

2. - ACTIVTY SEQUENCING

• Armed with the Activity Definitions we can move

onto the Activity Sequencing Phase of the

process:

Step 2 - Activity Sequencing

• Identifies and documents activities’

dependencies upon each other.

Activity Sequencing

• performed on paper or computer software;

• purpose is logical planning only;

• an understanding is achieved through a manual

process - remember the software is only a tool;

• manual process is useful where little detail exists

or for small projects;

Activity Sequencing - Inputs

EXERCISE No. 3

• Activity Sequencing is step 2 in the process of

Time Management and again requires certain

inputs and outputs.

• Attempt to identify those Inputs are.


• Activity List;

• Constraints & Assumptions;

• Product Description;

• Mandatory Dependencies;

• Discretionary Dependencies;

• External Dependencies;

Activity List:

• This is the activity list is derived from the first phase of the process.

Constraints & Assumptions:

• These are the Constraints & Assumptions derived from the first phase of the process.


Product Description:

• documents characteristics of the project;

• in construction this is normally contained within drawings, specifications and related documentation;

• project characteristics determine the actions e.g layout of a gold mine;

• effects may be apparent through activity list but should be confirmed at this point for accuracy;


Dependencies:

• a dependency is reliance by one activity on

another:

• activities or parts of activities cannot be done until

another activity or part of activity is done;

• requires asking “which activities depend on others

for completion?”

• in a dependency the first activity is a predecessor

followed by a successor;


Mandatory Dependencies:

• a Mandatory Dependency is one inherent to the

construction method or sequence;

• they usually involve physical limitations - eg brick

wall cannot be started until footings are placed

and cured;

• mandatory dependencies are referred to as

“Hard Logic”;


Discretionary Dependencies:

• referred to as “Soft Logic”;

• these dependencies are defined by the team;

• must be documented - no rules to govern them;

• must be used carefully - may restrict you later;

• are usually based on project manager’s

discretion based on “Best Practices” or available

alternatives;


External Dependencies:

• are factors outside the project that affect activity

sequencing of activities e.g. outcome of

Environmental Impact Studies prior to project

commencing;



The logic of a dependency occurs in 1 of 4 ways:

1 Finish to Start - predecessor must finish before

successor can start e.g. place reinforcement

before concrete pour;

2 Start to Start - predecessor must start before

successor can start e.g. site clearance before

topsoil removal;


3 Finish to Finish - predecessor must finish before

successor finishes, similar to Start - Start eg site

clearance must finish before topsoil removal can

finish;

4 Start to Finish - predecessor must start before

successor finishes eg electrical cable installation

must start before a pump installation can be

finished;


• finish-to-start is most common type of logic;

• start-to-finish rarely used, only by professional

scheduling engineers;

• start-to-start, finish-to-finish, or start-to-finish

relationships with project management software

can produce unexpected results since they are

not consistently implemented.


“LAG”:

• Lag is an appreciation of activity relationships;

• Site Clearance & Topsoil with a Start - Start

dependency is typical;

• lags are similar to discretionary dependencies;

• they are subjective and must be fully

documented and substantiated;

Activity Sequencing - Tools

• We have now identified our activities through the

WBS and Activity Definition Process:

• We should now be able to determine their

relationship and use a diagramming tool to

display them.

Activity Sequencing - Tools

EXERCISE No. 4

• The noise wall activities were identified through

the WBS and Activity Definition Process:

• We should now be able to determine their logical

relationship and use a diagramming tool to

display them. Nominate, for each activity, what

it’s predecessor is.

1.01 Contract Award

2.01 Site Preparation

2.02 Excavate Footings

3.01 Order/Deliver Bricks

3.02 Order/Deliver Concrete

4.01 Pour footings (S/C)

4.02 Concrete curing

4.03 Erect walls

4.04 Hang gate

5.01 Practical Completion

Activity ListPredecessor

-

1.01

2.01

1.01

1.01

2.02 & 3.02

4.01

4.02

4.03

4.04

Diagrammatic Representation

There are two principal ways of showing this

information:

• Network Diagrams;

• Bar “Gantt” Charts;

Gantt charts are part of Schedule Development.

Statistical Programming Techniques:

• for use in sophisticated programming situations

only;

• known as PERT and GERT;

• Program (Graphical) Evaluation & Review

Techniques;

• rely on probability analysis of activity durations

and likelihood of achieving them;


Network Diagrams;

• organisation of activities and relationships in a

diagrammatic form;

• highlights important relationships;

• allows analysis and review;

• is most common form in software packages;

• known as activity on node;


Network Diagrams;


Repair Walls

Buy Paint & Grout

Sand & Clean

Remove Grout

Paint Walls

Regrout

Install Fittings

EXERCISE No. 5

• Prepare a Network Diagram (activity on node) for

the brick security wall as per the actvity list

developed.


Security Wall Network Diagram


Award

Site Prep

Order Concrete

Excavate

Order Bricks

Pour Concrete

Erect Walls

Hang Gate

Curing

PC


• network diagrams show paths & dependence

of activities;

• demonstrates how delay in one affects a

successor;

• ultimately after further development it helps

define the CRITICAL PATH;

• this is the path of activities that take the

longest time to complete;

• this is the path where a delay in an activity will

delay the project by the same amount;

• it also shows the path where time can be saved

because acceleration of those activities will lead

to earlier completion;

• the network diagram is consequently an

important communication tool for discussion with

project participants.


Our outputs for the Activity Sequencing step are:

• Network Diagram

• Updated Activity List

Activity Sequencing - Outputs

Network Diagram:

• schematic display of project activities and

relationships;

• produced manually or by computer;

• maybe detailed by summary or detail activities;

• provide a narrative summary to accompany

diagram;

• is NOT a PERT or GERT;


Updated Activity List:

• similar to WBS update during Activity Definition;

• sequencing phase identifies activities not

previously listed or detailed;

• list is updated to accommodate new or redefined

activities;


• Assemble project scope, historical data, WBS

and identify constraints & assumptions;

• Create an Activity List, document supporting

detail and update WBS;

• Identify logic and relationships between activities

to develop into a network diagram;

• Evaluate & analyse network - refine where

possible;

SUMMARY TO DATE

TIME MANAGEMENT PROCESS

• Definition of activities;

• Sequencing of activities;

• Estimating duration of activities;

• Schedule development;

• Monitor and control of schedule;

time management 641 topic 03 activity sequencing

Documents

activity sequencing

activity sequencing

activity definitions

activity definition

activty sequencing

date slide

substantiated slide

finish predecessor