Engineering Project Management Discussionsite.iugaza.edu.ps/oabdalhadi/files/2015/02/... ·...

Engineering

Project Management

Discussion

By :

Eng. Osama M. Abdalhadi

2015

Engineering Project Management Discussion 2015

1 Eng. Osama M. Abdalhadi

Introduction:

Bill of Quantity: (BOQ) is a document prepared by the quantity surveyor that provides

project specific measured quantities of the items of work identified by the

drawings and specifications in the tender documentation.

Contract Duration: The maximum time allowed in the contract for completion of all work

contained in the contract documents.

eg.

Project Duration: (Planned) The schedule time to execute the project tasks, it must be less

than or equal contract duration.

Productivity Rate: The quantity produced or constructed by one team (technician + worker)

over a specified time period. (i.e. Builder productivity = 20 m2/d).

Notes:

An accurate database should be established by using normal historical rates of efficient

contractors.

One method of establishing production rates is to divide the total quantity of an item on

previously completed projects by the number of days/hours the contractor used to complete the

item.

The most accurate data will be obtained from site visits or review of project records.

The production rates used should be based on the desired level of resource commitment (labor,

equipment, etc.) deemed practical given the physical limitations of the project.

Working day equal 8 hours.

Task Duration: is the quantity from contract over ( productivity rate for one team product

number of teams).

• Usually the productivity rate product by 1.2 (20%) for unexpected conditions.

Task Duration =1.2 × 𝑄𝑢𝑎𝑛𝑡𝑖𝑡𝑦 𝑓𝑟𝑜𝑚 𝑐𝑜𝑡𝑟𝑎𝑐𝑡

𝑃𝑟𝑜𝑑𝑐𝑡𝑖𝑣𝑖𝑡𝑦 𝑟𝑎𝑡𝑒 × 𝑛𝑢𝑚.𝑜𝑓 𝑡𝑒𝑎𝑚𝑠

Calendar Days: All days in a month, including weekends and holidays.

Working Days: Any day (other than weekend holiday or legal holiday) on which legal

business can be conducted.



The following table show names of most common term in construction work.

EQUIPMENT MAN POWER

Type Arabic Trade Arabic

Compressor الكمبريسور Project Manager مدير المشروع

Water Pump مضخة مياه Q.C Engineer مهندس األمان الجودة

Generator مولد Site Engineer مهندس الموقع

Cutting Machine ماكنة قطع الحديد Q. Surveyor حاسب كميات

Welding Machine ماكنة اللحام Secretary سكرتير

Crane رافعة / ونش Forman مسئول عمال

Pick Up شحن صغير Surveyor مساح

Truck )شاحنة )نقل الرمل Guard حارس

Water Tanker خزانات المياه Company Labors عمال الشركة

Loader كباش من غير عجالت Driver سواق

Wheel loader كباش بعجالت Plumber/Labor سباك

Plate Compactor طن 8الدماكة Lab.Tech فني مختبر

Compactor 25 t طن 25الدماكة Mechanic ميكانيكي

Concrete Mixer )خالطة باطون )المكسر Black Smith/Labor حداد أبواب

Concrete Pump )مضخة الباطون )المشافاة Steel Fixer/Labor حداد قضبان حديد

Vibrators الرجاج Shutterer/Labor طوبرجي

Forklift مزليق Electrician/Labor كهربائي

Grader قرادير Mason/Labor بناء

JCP Excavator باقر Carpenter/labor نجار

St. Troweled Mach. هليوكبتر Plasterer/labor قصير

Tiler/labor بليط

Painter/Labor دهين

Aluminum/Labor فني ألمنيوم

Insulation Tech. فني عزل

Interlock tiler/Labor بالط انترلوك

The following Productivity rate based on Quantity Surveying & Specification by Eng. Kahlid Isa

Task Team Productivity / Hour Productivity / Day

Excavation sandy soil Loader + Truck 25 M3 200 M

3

Excavation clay soil Loader + Truck 10 M3 80 M

3

Concrete

Plain Shutterer + Labor 5.5 M3 41 M

3

Footing B 250 Shutterer + Steel Fixer 0.8 M3 6 M

3

Neck Columns Shutterer + Steel Fixer 0.34 M3 3 M

3

Ground Beam Shutterer + Steel Fixer 5.8 M3 44 M

3

Ground Floor Shutterer + Steel Fixer 10.0 M3 75 M

3

Columns Shutterer + Steel Fixer 0.46 M3 3.0 M

3

Staircase Shutterer + Steel Fixer 0.80 M3 6.0 M

3

Slabs Shutterer + Steel Fixer 1.4 M2 11 M

2



Task Team Productivity / Hour Productivity / Day

Block work Mason + Labor 2.5 M2 19 M

2

Internal Plastering Plasterer + labor 2.0 M2 15 M

2

External Plastering Plasterer + labor 1.60 M2 12 M

2

Tile work Tiler + labor 2.0 M2 15 M

2

Ceramic work Tiler + labor 1.5 M2 11 M

2

Marble work Technician + worker 1.2 M2 9 M

2

Painter (acrylic) Painter + Labor 12.0 M2 90 M

2

Painter ( Tambour) Painter + Labor 1.3 M2 10 M

2

Examples:

1- Calculate Task Duration for Concrete work:

Solution:

Productivity of foundation work= 6 m3/d.

Try one team


𝑃𝑟𝑜𝑑𝑐𝑡𝑖𝑣𝑖𝑡𝑦 𝑟𝑎𝑡𝑒 × 𝑛𝑢𝑚.𝑜𝑓 𝑡𝑒𝑎𝑚𝑠 = 1.2 ×

50

6 × 1= 10 𝑑𝑎𝑦𝑠 ‼

So try to use 4 teams = 1.2 ×50

6 × 4≅ 3 𝑑𝑎𝑦𝑠 … . . . 𝒂𝒄𝒄𝒆𝒑𝒕𝒂𝒃𝒍𝒆

2- Calculate Task Duration for Excavation work :sand soil

Area of the bulding = 1000 m2 Excavation depth= 1.5 m

Solution:

Productivity of Excavation work= 200 m3/d. Try one team



500

200× 1= 3 𝑑𝑎𝑦𝑠. . 𝑶𝑲

But !! The quantity of excavation is engineering quantity, in the sit contractor excavate all

building area so.

Quantity of Excavation = 1000 × 1.5 = 1500 m3

Productivity of Excavation work= 200 m3/d. Try one team

Task Duration =1.2 × 𝑄𝑢𝑎𝑛𝑡𝑖𝑡𝑦 𝑓𝑟𝑜𝑚 𝑠𝑖𝑡𝑒


1500

200× 1≅ 8 𝑑𝑎𝑦. . 𝑵𝒐𝒕 𝑶𝒌

Try Two teams = 1.2 ×1500

200 × 2≅ 5 𝑑𝑎𝑦𝑠 … . . . 𝒂𝒄𝒄𝒆𝒑𝒕𝒂𝒃𝒍𝒆



Other Factors Which Influence Project Duration:

1- Effects of maintenance.

2- Curing time and waiting periods between successive tasks. (eg. paving & concrete).

3- Seasonal limitations for certain items.

4- Conflicting operations of adjacent projects.

5- Time for reviewing false-work plans, shop drawings.

6- Coordination with utilities.

7- Time to obtain necessary permits.

Work Breakdown Structure (WBS)

A tree structure, which shows a subdivision of effort required to achieve an objective of a project.

WBS is a tool used to define and group a project's discrete or tasks in a way (levels) that helps

organize and define the total work scope of the project.

Work Description Quantity Productivity

Quantity/d

Option Table

( work days for n teams) Labor Time

1 2 3 4 5 Teams Days

Excavation

For Foundation 1500 m3 200 8 5 3 2 1 2 5

Concrete work

Foundation B250 50 m3 6 10 5 3.3 2.5 2 4 3



Work breakdown structure



Project Duration Determination Techniques:

1. Bar Charts (Gantt charts)

2. Critical Path Method (CPM).

a) Activity on Node (AON).

b) Activity on Arrows (AOA).

3. Program Evaluation Review Technique (PERT).

1. Bar Charts (Gantt charts):

A graphical representations of projects with specific completion dates and activities.

Bars or lines are drawn proportional to the planned duration of each activity.

Procedure to develop Gantt Chart:

1. Break a project down into separate activities based on B.O.Q.

2. Based on production rates determine the duration of each activity.

3. Determine the start day of project then related each task.

Advantage:

1. Simple to develop and easy to understand.

2. Offer a good method of determining contract time.

Disadvantages:

1. Do not show the interrelationship and inter-dependency among the various phases of work.

2. Difficult to properly evaluate when construction changes occur

3. Not recommended for large or complex construction projects.




Working from the project's beginning and defining individual project tasks and the number of days

to perform each task, a logical diagrammatic representation of the project is developed.

CPM shows which tasks of a project will change the completion date if they are not completed on

time. Because of the size and complexity of most projects, this method is most often applied using a

computer software program.

Procedure to develop CPM:

1. Break a project down into separate activities called tasks.

2. Determine the relationship of these activities to one another.

3. A diagrammatic representation of the project is developed. Each activity is shown as an

arrow leading to a node, which indicates the completion of an event of time.

4. The time to complete each activity is shown on each arrow to indicate the duration.

Advantages

1. An accurate technique for determining contract time and verifying that the project can be

constructed as designed and with identified construction sequences.

2. A useful tool for project managers in monitoring a project.

3. Determine delays can be identified and corrective measures to keep a project on schedule

Disadvantages

1. Requires experienced and knowledgeable staff to be used effectively.

2. Require regular updates.

Tasks Relationship:

Finish to Start (F.S) :

The predecessor must finish before the successor can start or

The successor task can’t start until the predecessor task finishes.(most common type)

تبدأ المهمة الالحقة عند انتهاء المهمة السابقة.

eg. -The Backfilling works can’t start before neck columns works.

-The Painting works can’t start before Plastering work

-You must write a report before you can edit it

Start to Start (S.S)

The predecessor must start before the successor can start or

The successor can’t start until the predecessor starts.

مباشرة السابقة المهمة بدابة مع الالحقة المهمة تبدأ

eg. - The Frame door installation works on fourth floor start with the same installing

doors in the first floor



Finish to Finish (F.F)

The predecessor must finish before the successor can finish or

The successor task can’t finish until the predecessor task finishes

مباشرة السابقة المهمة نهاية مع الالحقة المهمة تنتهي

eg. - The Steel works on footing can’t finish until shuttering work on footing finish.

Writing a document is required to finish before editing the document (successor) can finish

Start to Finish (S.F)

The predecessor must start before the successor can finish. or

The successor task cannot finish until the predecessor task starts (not logic on construction )

مباشرة الالحقة المهمة نهاية مع السابقة المهمة تبدأ

eg. The first security guard shift (successor) cannot finish until the second security guard

shift (predecessor) starts. Loop Tasks

- Excavation works can’t start before Footing works finish.

Lag/slack:

the amount of time between related activities, this amount take negative or positive values

F.S

S.S Lag (+3)

S.S

F.F

F.S

Lag (-2)



CPM Methods:

A. Activity on Node(AON)/ Precedence Diagram Method(PDM)

B. Activity on Arrows (AOA)/ /Arrow Diagramming Method (ADM)

A. Precedence Diagram Method(PDM)

A network diagram is where boxes are used to represent an activity, with arrows linking them

together to show the sequence in which they are performed.

or

Example: Draw PDM , Determine CPM, Calculate ES, EF, LS, LF, TF, FF for each Task

Calculate the project Duration.

Solution:

Early Start Date (ES). The earliest point in time that an activity can start, provided that all

activities before it have finished.

. الوقت الالزم لألنشطة التي تسبقه بعين االعتبار أخذ ةحال يف بالنشاط للبدء نممك وقت أبكر

Early Finish Date (EF). The earliest point in time that an activity can finish ,it is merely the

duration of the activity after its early start. EF = E.S+D

.المبكرة تهيوبدا النشاط مدة عومجم ووه ، النشاط هاءنإل نممك وقت أبكر



Late Finish Date (LF). The latest possible point in time that an activity can be completed

without delaying the project finish date.

له المحدد خاريالت يف بكامله المشروع هاءنإ باإلمكان بقىي بٍحث ، النشاط هاءنإل نممك وقت رآخ

Late Start Date (LS). The latest possible point in time that an activity can begin without

delaying the project finish date. LS =LF-D

المتأخرة تهيهان نم النشاط مدة حرطة جنتي وهى ، بالنشاط للبدء نممك وقت رآخ

Total Float (TF). The amount of time that a schedule activity can be delayed or extended from

its early start date without delaying the project finish date.

وعرالمش مدة ةبإطال التسبب بدون ، ةرالمبك تهيهان وقت نع شاطنال هاءنإ رتأخ مقدارو ه

Activity Total Float (TF) = Activity LS –Activity ES

= Activity LF –Activity EF



Free Float (FF). The amount of time that a schedule activity can be delayed without delaying

the early start date of any successor.

الحق شاطن ألي ةرالمبك ايةالبد خيربتأ التسبب بدون ، ةرالمبك تهيهان وقت نع النشاط هاءنإ رتأخ مقدار وه

Free Float for Task A= 0

Free Float for Task B = 1

Free Float (FF) = min. ES of Activity’s successors – Activity EF

Back again to example:

Critical path is A, C, D, E.

The Duration of project is 13 days.

Notes:

1. The TF & FF For Critical Tasks = Zero, So you can determine CPM from it.

2. The Project Duration is summation of duration for each Critical Tasks.

3. LS – ES = LF – EF for each tasks.

4. TF ≥ 𝑭𝑭

Task A

Task B

Task C



Example (2):Draw PDM, Complete the table, and Determine the CPM

Solution:

Critical Path is A, C, E, G, H

Activity Preceded

by Duration

Start Finish FF TF

E.S L.S E.F L.F

A ---- 3 0 3 0 3 0 0

B A 2 3 5 6 8 3 3

C A 5 3 8 3 12 0 0

D ---- 3 0 3 9 12 9 0

E B,C 4 8 12 8 12 0 0

F D 5 3 8 16 21 13 13

G E,D 6 12 18 12 18 0 0

H G 3 18 21 18 21 0 0



Example (3): Draw PDM , Determine CPM, Calculate ES, EF, LS, LF, TF, FF for each Task


Solution: Critical paths are : Start-A-C-G-N-Finish & Start-A-D-I-L-M-Finish

Project duration is : 30 days



Home Work:

Draw PDM , Determine CPM, Calculate ES, EF, LS, LF, TF, FF for each Task


A.

B.

C.

Activity Preceded by Duration A ----- 8

B ----- 4

C A, B 3

D A, B 8

E A, B 5

F C, D, E 5

Activity Preceded by Duration

A ----- 3

B ----- 2

C A 4

D A 5

E B 3

F E 6

G E 4

H C, D, F 5

I H, G 7

J H 2

K I, G 5

Activity Preceded by Duration

A ----- 2

B A 4

C A 2

D A 12

E A 20

F B, C 6

G B, C 3

H F, G 5

I F, G 4

J H, I 2

K D, H, I 4

L E, J, K 3



Project Duration Determination Techniques:

1. Bar Charts (Gantt charts)


a) Activity on Node (AON) / Precedence Diagram Method(PDM)

b) Activity on Arrows (AOA)/ Arrow Diagramming Method (ADM)

3. Program Evaluation Review Technique (PERT).

b. Activity-on-Arrow (AOA) networks:

AOA diagram is drawn using circles as the nodes, with nodes represents the beginning and ending

points of the arrows or tasks. Arrows act as activities or tasks in AOA diagram.

3. Program Evaluation and Review Technique (PERT).

A technique for estimating that applies a weighted average of optimistic, pessimistic, and most

likely estimates when there is uncertainty with the individual activity estimates.

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