Construction engineering and management
This presentation is the property of its rightful owner.
Sponsored Links
1 / 118

Construction Engineering and Management PowerPoint PPT Presentation


  • 76 Views
  • Uploaded on
  • Presentation posted in: General

Construction Engineering and Management . Instructor: Dr. Ayham Jaaron. Class Rules and Instructor Expectations Turn off your cell phone before you get inside the class room. Be on time and respect deadlines; late homework will not be accepted!

Download Presentation

Construction Engineering and Management

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Construction engineering and management

Construction Engineering and Management

Instructor:

Dr. AyhamJaaron


Construction engineering and management

ENGINEERING MANAGEMENT

  • Class Rules and Instructor Expectations

  • Turn off your cell phone before you get inside the class room.

  • Be on time and respect deadlines; late homework will not be accepted!

  • Participate and attend class: be ready and prepare well, that is the key to success!

  • Quizzes and exams will be closed-book.

  • Avoid Make-up/incomplete exams!


Construction engineering and management

ENGINEERING MANAGEMENT

Topics

1) Management Functions and introduction of construction project planning and scheduling

2)Construction scheduling techniques

3)Preparation and usage of bar charts

4)Preparation and usage of the Critical Path Method (CPM)

5)Preparation and usage of Precedence Diagramming Method (PDM)

6)Issues relating to determination of activity duration

7)Contractual provisions relating to project schedules

8)Resource leveling and constraining

9)Time cost tradeoff

10)Schedule monitoring and updating.

11)Communicating schedule

12) Project control and earned value Control

13) claims, Safety and Quality control


Construction engineering and management

What is the Project

ENGINEERING MANAGEMENT

In order to understand project management, one must begin with the definition of a project. A project can be considered to be any series of activities and tasks that :.

● Have a specific objective to be completed within certain specifications

● Have defined start and end dates

● Have funding limits

● Consume human and nonhuman resources (i.e., money, people, equipment)

● Are multifunctional (i.e., cut across several functional lines)


Construction engineering and management

ENGINEERING MANAGEMENT

OR

‘‘a temporary endeavor undertaken to create a unique product, service, or result’’


Construction engineering and management

Project Life Cycle

ENGINEERING MANAGEMENT


Construction engineering and management

Five Process group

ENGINEERING MANAGEMENT


Construction engineering and management

ENGINEERING MANAGEMENT


Construction engineering and management

ENGINEERING MANAGEMENT

Successful project management can then be defined as having achieved the project objectives:

●Within Time

● Within Cost

● At the desired performance/Technology level

● While utilizing the assigned resources effectively and efficiently

● Accepted by the customer


Construction engineering and management

What is Project Management

ENGINEERING MANAGEMENT

Project management is the planning, organizing, directing, and controlling of company resources for a relatively short-term objective that has been established to complete specific goals and objectives.


Construction engineering and management

ENGINEERING MANAGEMENT

The potential benefits from project management are:

● Identification of functional responsibilities

● Minimizing the need for continuous reporting

● Identification of time limits for scheduling

● Identification of a methodology for

trade-off analysis.

● Measurement of accomplishment

against plans


Construction engineering and management

ENGINEERING MANAGEMENT

The above definition requires further comment. Classical management is usually considered to have five functions or principles:

● Planning

● Organizing

● Staffing

● Controlling

● Directing


Construction engineering and management

ENGINEERING MANAGEMENT

Planning

– Where the organization wants to be in the future and how to get there.

Organizing

– Follows planning and reflects how the

organization tries to accomplish the plan.

– Involves the assignment of tasks, grouping of

tasks into departments, and allocation of resources.


Construction engineering and management

ENGINEERING MANAGEMENT

Leading & Staffing

– The use of influence to motivate employees to

achieve the organization's goals.

– Creating a shared culture and values,

communicating goals to employees throughout

the organization, and infusing employees to

perform at a high level.

Controlling

– Monitoring employees' activities, determining if the organization is on target toward its goals, and making corrections as necessary


Construction engineering and management

Management Skills

ENGINEERING MANAGEMENT

 Conceptual Skill—the ability to see the organization as a whole and the relationship between its parts.

 Human Skill—The ability to work with and through people.

 Technical Skill—Mastery of specific functions and specialized knowledge


Construction engineering and management

Constraints of the project

ENGINEERING MANAGEMENT

Project management is designed to manage or control company resources on a given activity, within time, within cost, and within performance. Time, cost, and performance are the constraints on the project.


Construction engineering and management

Resources

ENGINEERING MANAGEMENT

We have stated that the project manager must control company resources within time, cost, and performance. Most companies have six resources:

● Money

● Manpower

● Equipment

● Facilities

● Materials

● Information/technology


Construction engineering and management

ENGINEERING MANAGEMENT

  • Actually, the project manager does notcontrol any of these resources directly, except perhaps money (i.e., the project budget).

  • Resources are controlled by the line managers.

  • The project manager is responsible for coordinating and integrating activities across multiple, functional lines. The integration activities performed by the project manager include:


Construction engineering and management

ENGINEERING MANAGEMENT

● Integrating the activities necessary to develop a project plan

● Integrating the activities necessary to execute the plan

● Integrating the activities necessary to make changes to the plan


Construction engineering and management

ENGINEERING MANAGEMENT

Project Planning, Scheduling, and Control

1


Construction engineering and management

Planning and Scheduling

ENGINEERING MANAGEMENT

  • Planning and scheduling are two terms that are often thought of as synonymous

  • They are not!

  • Scheduling is just one part of the planning effort.


Construction engineering and management

ENGINEERING MANAGEMENT

  • Project planning serves as a foundation for several

  • related functions such as cost estimating, scheduling,

  • and project control.

  • Project scheduling is the determination of the timing and sequence of operations in the project and their assembly to give the overall completion time


Construction engineering and management

ENGINEERING MANAGEMENT

Planning is the process of determining how a project will be undertaken. It answers the

questions:

1. “What” is going to be done,

2. “how”,

3. “where”,

4. By “whom”, and

5. “when” (in general terms: start and finish).

Scheduling deals with “when” on a detailed level… See Figure 1 .


Construction engineering and management

ENGINEERING MANAGEMENT

The Plan

What

How much

when

By whom

where

How

Why

Figure 1 . Planning and Scheduling


Construction engineering and management

The Plan

ENGINEERING MANAGEMENT

Project management plan can be defined as a ‘‘formal, approved document that defines how the project is executed, monitored and controlled”.

The plan can include elements that has to do with scope, design and alternate designs, cost, time, finance, land, procurement, operations, etc.


Construction engineering and management

WHY SCHEDULE PROJECTS ?

ENGINEERING MANAGEMENT

1- To calculate the project completion.

2- To calculate the start or end of a specific activity.

3-To expose and adjust conflict between trades or subcontractor.

4- To predict and calculate the cash flow .

5-To evaluate the effect of changing purchasing orders .


Construction engineering and management

ENGINEERING MANAGEMENT

6- To improve work efficiency.

7- To resolve delay claims , this is important in critical path method ‘CPM’ discussed later..

8- To serve as an effective project control tool .


Construction engineering and management

The Tripod of Good Scheduling System

ENGINEERING MANAGEMENT

The Human Factor : A proficient scheduler or scheduling team.

2. The Technology : A good scheduling computer system (software and hardware)

3. The Management : A dynamic, responsive, and supportive management.

  • If anyone of the above three ‘‘legs’’ is missing, the system will fail.


Construction engineering and management

Scheduling and project management

ENGINEERING MANAGEMENT

Planning, scheduling, and project control are extremely important components of project management.

project management includes other components :

  • cost estimating and management,

  • procurement,

  • project/contract administration,

  • quality management,

  • and safety management.

  • These components are all interrelated in different ways.


Construction engineering and management

ENGINEERING MANAGEMENT

Ch.2: Bar (Gantt) Charts

2


Construction engineering and management

DEFINITION AND INTRODUCTION

ENGINEERING MANAGEMENT

  • A bar chart is ‘‘a graphic representation of project activities, shown in a time-scaled bar line with no links shown between activities’’

  • The bar may indicate continuous work from the start of the activity until its end.

  • or

  • Non continuous (dashed) bars are sometimes used to distinguish between real work (solid line) and inactive periods (gaps between solid lines)


Construction engineering and management

ENGINEERING MANAGEMENT

  • Before a bar chart can be constructed for a project, the project must be broken into smaller, usually homogeneous components, each of which is called an activity, or a task.

Item Activity

M 10 Mobilization

Bars ( Month or Year..etc )


Construction engineering and management

ADVANTAGES OF BAR CHARTS

ENGINEERING MANAGEMENT

  • 1- Time-scaled

  • 2- Simple to prepare

  • 3- Bars can be dashed to indicate work stoppage.

  • 4- Can be loaded with other information (budget, man hours, resources, etc.)


Construction engineering and management

ENGINEERING MANAGEMENT

Bar Charts Loaded with More Info.

Such as : budget, man hours and resources .

500$

220$

400$

850$

140$

500$

900$

10 12 7 11 10 9 15


Construction engineering and management

DISADVANTAGES OF BAR CHARTS

ENGINEERING MANAGEMENT

1- Does not show logic of why mistakes occur.

2- Not practical for projects with too many activities

  • As a remedy, we can use bar charts to show:

    1. A small group of the activities (subset)

    2. Summary schedules


Construction engineering and management

ENGINEERING MANAGEMENT

Basic Networks

3


Construction engineering and management

DEFINITION AND INTRODUCTION

ENGINEERING MANAGEMENT

  • A network is a logical and chronological graphic representation of the activities (and events) composing a project.

  • Network diagrams are the preferred technique for showing activity sequencing.


Construction engineering and management

ENGINEERING MANAGEMENT

Two classic formats

AOA: Activity on Arrow

AON: Activity on Node

Each activity labeled with

Identifier (usually a letter/code)

Duration (in std. unit like days)

There are other variations of labeling

There is 1 start & 1 end event

Time goes from left to right


Construction engineering and management

Arrow Diagramming Method (ADM)

ENGINEERING MANAGEMENT

1. Also called activity-on-arrow (AOA) network diagram or (I-J) method (because activities are defined by the form node, I, and the to node, J)

2. Activities are represented by arrows.

3. Nodes or circles are the starting and ending points of activities.

4. Can only show finish-to-start dependencies.


Construction engineering and management

Basic Logic Patterns for Arrow Diagrams

ENGINEERING MANAGEMENT

Node (Event) i

Node (Event) j

i

Activity Name

j

j > i

Each activity should have a unique i – j value

(a) Basic Activity


Construction engineering and management

ENGINEERING MANAGEMENT

A

B

2

4

10

12

(b) Independent Activities

A

B

3

6

9

(c) Dependent Activities


Construction engineering and management

ENGINEERING MANAGEMENT

4

A

C

6

8

B

2

Activity C depends upon the completion of both Activities A & B

(d) A Merge

6

B

A

2

4

C

8

Activities B and C both depend upon the completion of Activity A

(e) A Burst


Construction engineering and management

ENGINEERING MANAGEMENT

12

18

A

C

16

D

B

14

20

Activities C and D both depend upon the completion of Activities A and B

(f) A Cross


Construction engineering and management

Example

ENGINEERING MANAGEMENT

Draw the arrow network for the project given next.


Construction engineering and management

ENGINEERING MANAGEMENT

Solution :

B

D

30

A

E

50

10

20

40

C


Construction engineering and management

Dummy activity (fictitious)

ENGINEERING MANAGEMENT

  • Used to complete logic,

  • It has a duration of “0”

  • It consumes no resources

  • It is only used to show relationships


Construction engineering and management

ENGINEERING MANAGEMENT

A

4

10

Divide node to correct

B

(a) Incorrect Representation

A

4

10

B

Dummy

11

(b) Correct Representation


Construction engineering and management

Example

ENGINEERING MANAGEMENT

Draw the arrow network for the project given next.


Construction engineering and management

Solution :

ENGINEERING MANAGEMENT

B

A

D

40

10

20

30

C

Improper solution

B

30

Dummy

D

A

50

10

20

40

C

proper solution


Construction engineering and management

50

50

Example

ENGINEERING MANAGEMENT

Draw the arrow network for the project given next.


Construction engineering and management

Solution :

ENGINEERING MANAGEMENT

B

D

30

Dummy 1

E

A

50

60

10

20

Dummy 2

F

C

40


Example st adolf s hospital

Immediate

ActivityDescriptionPredecessor(s)Responsibility

ASelect administrative and medical staff.—Johnson

BSelect site and do site survey.—Taylor

CSelect equipment.AAdams

DPrepare final construction plans and layout.BTaylor

EBring utilities to the site.BBurton

FInterview applicants and fill positions inAJohnson

nursing, support staff, maintenance,

and security.

GPurchase and take delivery of equipment.CAdams

HConstruct the hospital.DTaylor

IDevelop an information system.ASimmons

JInstall the equipment.E,G,HAdams

KTrain nurses and support staff.F,I,JJohnson

Example: St. Adolf’s Hospital

Draw the project network using AOA and AON Methods?


Construction engineering and management

ENGINEERING MANAGEMENT

Removal of Redundant Dummies

Original Diagram

Diagram after removal of redundant dummies

A

B

A

B

(a)

A

B

A

B

(b)

C

C


Construction engineering and management

ENGINEERING MANAGEMENT

Original Diagram

Diagram after removal of redundant dummies

A

C

(c)

A

C

B

E

B

E

A

C

A

C

(d)

B

E

B

E


Construction engineering and management

L

J

25

F

M

H

15

45

40

G

E

B

35

20

5

D

C

A

30

10

K

ENGINEERING MANAGEMENT

AOA Representation


Construction engineering and management

NODE NETWORKS METHOD (AON)

ENGINEERING MANAGEMENT

Activity number

Link

10

A

20

B

Activity name

a) Independent Activities

10

A

Link

20

B

B depends on A

b) Dependent Activities


Construction engineering and management

30

C

10

A

20

B

40

D

ENGINEERING MANAGEMENT

10

A

C depends on A & B

D depends on C

40

D

30

C

20

B

c) A Merge Relationship

B depends on A

C depends on B

D depends on B

d) A Burst Relationship


Construction engineering and management

D

A

B

C

E

ENGINEERING MANAGEMENT

D

A

Start

Dummy

Finish

Dummy

B

C

E

e) Start & Finish Dummy Activities (usually added to provide one starting node and one ending node if more than one is available).


Construction engineering and management

59

Example

ENGINEERING MANAGEMENT

Draw the arrow network for the project given next using AON method.


Construction engineering and management

ENGINEERING MANAGEMENT

Solution :

B

D

A

E

C


Construction engineering and management

61

Example

ENGINEERING MANAGEMENT

Draw the arrow network for the project given next.


Construction engineering and management

ENGINEERING MANAGEMENT

Solution :

B

A

D

C


Construction engineering and management

63

63

63

Example

ENGINEERING MANAGEMENT

Draw the arrow network for the project given next.


Construction engineering and management

ENGINEERING MANAGEMENT

Solution :

B

D

A

End

E

C

F


Construction engineering and management

Lags and Leads

ENGINEERING MANAGEMENT

In some situations, an activity cannot start until a certain time after the end of its Predecessor.

Lag is defined as a minimum waiting period between the finish (or start) of an activity and the start (or finish) of its successor.

Arrow networks cannot accommodate lags. The only solution in such networks is to treat it as a real activity with a real duration, no resources, and a $0 budget.


Construction engineering and management

Examples

ENGINEERING MANAGEMENT

Place Concrete

3

3

Strips Forms

2

A lag in a node network

Place Concrete

Cure Concrete

Strips Forms

A lag in an arrow network


Construction engineering and management

ENGINEERING MANAGEMENT

The term leadsimply means a negative lag. It is seldom used in construction. In simple language: A positive time gap (lag) means ‘‘after’’ and a negative time gap (lead) means ‘‘before.’’


Construction engineering and management

ENGINEERING MANAGEMENT

Recommendations for Proper Node Diagram Drawing

Correct

Incorrect


Construction engineering and management

ENGINEERING MANAGEMENT

B

A

B

A

A

B

A

B

Improper

proper


Construction engineering and management

ENGINEERING MANAGEMENT

Improper

Proper


Construction engineering and management

ENGINEERING MANAGEMENT

Improper

Proper


Construction engineering and management

ENGINEERING MANAGEMENT

A

A

Start

B

B

C

C

Improper

Proper

(a) Do not start a network with more than one node


Construction engineering and management

ENGINEERING MANAGEMENT

A

A

End

B

B

C

C

Improper

Proper

(a) Do not enda network with more than one node


Construction engineering and management

The Critical Path Method (CPM)

4


Construction engineering and management

ENGINEERING MANAGEMENT

Introduction

Suppose you decide with your friend to go in hunting trip.

You must do specific activity such that the trip well be at the right way. The following activity must be done.


Construction engineering and management

ENGINEERING MANAGEMENT

From chart you can see that the 3rd activity (preparing the jeep) have the longest period of time any delay with this activity leads to delay in the trip this activity is a “critical activity”

Critical activity : An activity on the critical path, such that any delay on the start or finish of a critical activity will result in a delay in the entire project

Critical path : The longest path in a network from start to finish


Construction engineering and management

ENGINEERING MANAGEMENT

Steps Required To Schedule a Project

The preparation of CPM includes the following four steps:

1- Determine the work activities:

The project must be divided into smaller activities or tasks .

Use WBS in scheduling by using an order of letters and numbers


Work breakdown structure wbs

Definition:WBS is a process by which the whole project system is broken up or divided into various sub-projects, tasks, and finally, work packages and activities.

During the process of breaking down the project, the project manager, staff and all involved are forced to think through all aspects of the project.

WBS is the most important element in the project implementation stage as it is essential for establishing budgets, schedules, and assigning responsibilities for staff.

Examples are provided in the following slides:

Work Breakdown Structure (WBS)


Construction engineering and management

ENGINEERING MANAGEMENT


Construction engineering and management

ENGINEERING MANAGEMENT


Construction engineering and management

ENGINEERING MANAGEMENT


Construction engineering and management

ENGINEERING MANAGEMENT

2- Determine activity duration:

Duration = Total Quantity / Crew Productivity

The productivity has many sources :

1. The company

2. The market

3. Special books

Note: The scheduler must be aware about the non-working days , such as holydays or rain days, etc……


Construction engineering and management

ENGINEERING MANAGEMENT

3- Determine the logical relationships :

This step is a technical matter and obtained from the project manager and technical team, and logical relationships shouldn’t be confused with constraints

4- Draw the logic network and perform the CPM calculations


Construction engineering and management

ENGINEERING MANAGEMENT

5-Reiew and analyze the schedule:

1. review the logic

2. Make sure the activity has the correct predecessor

3. make sure there is no redundant activity


Construction engineering and management

ENGINEERING MANAGEMENT

6- Implement the schedule:

Definition: take the schedule from paper to the execution.

7-Monitor and control the schedule:

Definition: comparing what we planed with what actually done.

8-Revise the database and record feedback.

9-Resource allocation and leveling.(will discuss in chapter 6)


Construction engineering and management

Example

ENGINEERING MANAGEMENT

Draw the logic network and perform the CPM calculations for the schedule shown next.


Construction engineering and management

ENGINEERING MANAGEMENT

  • Forward pass calculations

In mathematical terms, the ES (early start) for activity j is as follows :

ESj=max( EFi)

where (EFi) represents the early finish for all preceding activities.

Likewise, the EF time for activity jis as follows :

EF j= ESj + Durj

where Dur j is the duration of activity j

Forward pass: The process of navigating through a network from start to end and calculating the completion date for the project and the early dates for each activity


Construction engineering and management

ENGINEERING MANAGEMENT

Solution :

5,13

13,22

B

8

D

9

0,5

13,19

22,23

A

5

G

1

E

6

5,11

11,14

C

6

F

3


Construction engineering and management

ENGINEERING MANAGEMENT

  • Backward pass calculations

In mathematical terms, the late finish LF for activity j is as follows :

(LFj =min(LSk

where (LSk) represents the late start date for all succeeding activities.

Likewise, the LS time for activity j (LS j) is as follows :

LS j= LFj- Dur j

where Dur j is the duration of activity

Backward pass: The process of navigating through a network from end to start and calculating the late dates for each activity. The late dates (along with the early dates) determine the critical activities, the critical path, and the amount of float each activity has.


Construction engineering and management

ENGINEERING MANAGEMENT

Solution :

5,13

13,22

B

8

D

9

0,5

13,22

5,13

13,19

22,23

A

5

G

1

E

6

0,5

16,22

22,23

5,11

11,14

C

6

F

3

19,22

10,16

CPM ( ES = LS , EF = LF , TF = FF = 0)


Construction engineering and management

Two MainTypes Of Floats

ENGINEERING MANAGEMENT

There are several types of float. The simplest and most important type of float is Total Float (TF)

  • Total float (TF): The maximum amount of time an activity can be delayed from its early start without delaying the entire project.

TF = LS – ES

or

TF = LF - EF

or

TF = LF - Dur- ES


Construction engineering and management

ENGINEERING MANAGEMENT

  • Free Float: may be defined as the maximum amount of time an activity can be delayed without delaying the early start of the succeeding activities (it may push succeeding activity up to a certain limit if it also has a float)

FFi = min(ESi+1) - EFi

where min (ESi+1) means the least (i.e., earliest) of the early start dates of succeeding activities (search for the earliest succeeding activities)


Construction engineering and management

ENGINEERING MANAGEMENT

In the previous example we can find the free float and total float for each activity as the following :

Activity C’s free float, FF = 11 - 11 = 0 days

And

Activity C’s total float, TF =16 - 11= 5 days …… and so on.

  • Critical activity

  • Note : We must always realize that FF ≤ TF


Construction engineering and management

Node Format

ENGINEERING MANAGEMENT

Activity ID

ES

EF

Activity Name

Duration

LF

LS

TF

FF


Construction engineering and management

ENGINEERING MANAGEMENT

Event Times in Arrow Networks

  • The early event time, TE, is the earliest date obtained to reach an event (going from start to finish).

  • The late event time, TL, is the latestdate obtained to reach an event (going from finish to start).

Examples

Perform the CPM calculations, including the event times, for the arrow network shown below.


Construction engineering and management

ENGINEERING MANAGEMENT

A

D

20

60

10

8

d2

G

d1

5

B

E

H

10

30

50

70

8

5

9

C

F

40

7

4

Arrow network for example


Construction engineering and management

ENGINEERING MANAGEMENT

The preceding logic is similar to that of the forward and backward passes: When you are going forward, pick the largest number. When you are going backward, pick the smallest number.

TEj

TEi

Act. Name

i

j

Dur.

TLj

TLi

CPM


Construction engineering and management

ENGINEERING MANAGEMENT

10

24

(0,10)

(10,18)

A

D

(0,10)

(11,19)

20

60

(19,24)

10

8

27

10

d2

(22,27)

0

19

G

10

27

(10,19)

(0,5)

(19,27)

d1

5

B

E

H

(5,10)

(10,19)

10

30

50

70

(19,27)

8

5

9

7

19

10

0

27

(0,7)

(7,11)

C

F

(8,15)

(15,19)

40

7

4

15


Construction engineering and management

Class Problem (1)

For the project information given below, use the AON method to:

1)calculate the total project duration? 3) Total float and free float for activities?

2)identify the critical activities?


Construction engineering and management

Class Problem (2)

Consider the following Data for a project:

1)Draw the network diagram using both techniques?

2)Calculate the critical path for the project? 3) what is free float for each activity?


Construction engineering and management

ENGINEERING MANAGEMENT

Definitions

Activity, or task: A basic unit of work as part of the total project that is easily measured and controlled. It is time- and resource consuming.

Backward pass: The process of navigating through a network from end to start and calculating the late dates for each activity. The late dates (along with the early dates) determine the critical activities, the critical path, and the amount of float each activity has.

Critical activity: An activity on the critical path. Any delay in the start or finish of a critical activity will result in a delay in the entire project.

Critical path: The longest path in a network, from start to finish, including lags and constraints.

.


Construction engineering and management

ENGINEERING MANAGEMENT

Early dates: The early start date and early finish date of an activity.

Earlyfinish (EF): The earliest date on which an activity can finish within project constraints.

Early start (ES): The earliest date on which an activity can start within project constraints.

Event: A point in time marking a start or an end of an activity. In contrast to an activity, an event does not consume time or resources.

Forward pass: The process of navigating through a network from start to end and calculating the completion date for the project and the early dates for each activity.

Late dates: The late start date and late finish date of an activity.

Late finish (LF): The latest date on which an activity can finish without extending the project duration.

Late start (LS): The latest date on which an activity can start without extending the project duration.


Construction engineering and management

Precedence Diagram

5


Construction engineering and management

ENGINEERING MANAGEMENT

The Four Types Relationships

Activities represented by nodes and links that allow the use of four relationships:

1) Finish to Start – FS

2) Start to Finish – SF

3) Finish to Finish – FF

4) Start to Start – SS


Construction engineering and management

ENGINEERING MANAGEMENT

Finish to Start (FS) Relationship

. The traditional relationship between activities.

. Implies that the preceding activity must finish

before the succeeding activities can start.

. Example: the plaster must be finished before the tile can start.

Plaster

Tile


Construction engineering and management

ENGINEERING MANAGEMENT

Star to Finish (SF) Relationship

. Appear illogical or irrational.

. Typically used with delay time OR LAG.

. The following examples proofs that its logical.

Erect

formwork

steel

reinforcement

Pour

concrete

5

SF

Order

concrete


Construction engineering and management

ENGINEERING MANAGEMENT

Finish to Finish (FF) Relationship

  • Both activities must finish at the same time.

  • Can be used where activities can overlap to a certain limit.

Erect

scaffolding

Remove

Old paint

FF/1

sanding

FF/2

Dismantle

scaffolding

painting

inspect


Construction engineering and management

ENGINEERING MANAGEMENT

Start to Start (SS) Relationship

  • This method is uncommon and non exists in project construction .

Clean surface

Spread grout

SS

Set tile

Clean floor area


Construction engineering and management

ENGINEERING MANAGEMENT

Advantages of using Precedence Diagram

  • No dummy activities are required.

  • A single number can be assigned to identify each activity.

    3. Analytical solution is simpler.


Construction engineering and management

ENGINEERING MANAGEMENT

Calculation

forward calculations

EF = ES + D

Calculate the Lag

LAGAB = ESB– EFA

Calculate the Free Float

FF = Min. (LAG)


Construction engineering and management

ENGINEERING MANAGEMENT

2) Backward calculations

For the last task LF=EF ,if no information deny that.

LS=LF-D

Calculate Total Float

TF = LS – ES OR LF – EF

TFi= Min (lag ij + TFj)

Determine the Critical Path


Construction engineering and management

Example

ENGINEERING MANAGEMENT

1) Forward pass calculations

4) Backward pass calculations

5) Calculate total Float (TF = LS – ES OR LF – EF)

B

D

F

H

A

0

0

0

0

1

2

11

16

20

1

1

9

2

5

11

4

16

1

20

0

0

2

0

0

11

0

0

16

0

0

20

0

0

21

2

11

16

20

21

4

5

3

0

G

C

E

0

0

2

7

11

5

5

4

10

6

14

0

3

10

0

3

14

3

3

20

7

11

17

2) Calculate the Lag ( LAGAB = ESB – EFA)

ES

Dur.

LS

3) Calculate the Free Float (FF) FF = min.( LAG)

EF

FF

TF

LF

112


Construction engineering and management

ENGINEERING MANAGEMENT

6) Determine the Critical Path

A

B

D

F

H

0

0

0

0

1

2

11

16

20

1

1

9

2

5

11

4

16

1

20

0

0

2

0

0

11

0

0

16

0

0

20

0

0

21

2

11

16

20

21

4

5

3

0

G

C

E

0

0

2

7

11

5

5

4

10

6

14

0

3

10

0

3

14

3

3

20

7

11

17

ES

Dur.

LS

The critical path passes through the critical activities where TF = 0

EF

FF

TF

LF

113


Construction engineering and management

Resource Allocation and Resource Leveling

6


Construction engineering and management

ENGINEERING MANAGEMENT

CATEGORIES OF RESOURCES

  • Labor

  • Materials

  • Equipment's.


Schedule updating and project control

Schedule Updating and Project Control

7


Construction engineering and management

Schedule Updating and Project Control

ENGINEERING MANAGEMENT

The most important use of schedules is project control : the scheduler compares actual performance with baseline performance.

What is Project Control

Project control comprises the following continuous process

1. monitoring work progress .

2.comparing it with the baseline schedule and budget.

3.finding any deviations .

4.taking corrective actions.


Construction engineering and management

ENGINEERING MANAGEMENT

Scheduleupdating

  • Schedule updating is just one part of the project control process.

  • Schedule updating must reflect

  • Actual work , and

  • involves change orders (CO) .


  • Login