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Construction Planning and Scheduling Construction Management Training Program For Technical Departments by AIT Extension & PRMP, Government Of Punjab. Santi Ch aroenpornpattana , Ph.D. Assistant Professor & Director Construction Engineering & Management Program
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Construction Planning and SchedulingConstruction Management Training Program For Technical Departments by AIT Extension & PRMP, Government Of Punjab SantiCharoenpornpattana, Ph.D. Assistant Professor & Director Construction Engineering & Management Program King Mongkut’s University of Technology Thonburi AIT Conference Center 18th August 2009
Planning and Scheduling Santi Charoenpornpattana, Ph.D. @2009
Three basic objectives of construction project management Cost Time Performance Santi Charoenpornpattana, Ph.D. @2009
What is “Planning” ? • General: “the function of selecting organization’s objectives and establishing the policies, procedures, and programs necessary for achieving them. • Project management context: “establishing an predetermined course of action within a forecasted environment” Santi Charoenpornpattana, Ph.D. @2009
Planning & Control / Time & Cost Time Cost Scheduling Cost Planning Planning Schedule Control Cost Control Control SantiCharoenpornpattana, Ph.D. @2009
Planning & Control / Time & Cost Tools Time Cost Bar Chart/ CPM Estimation/ Cost Planning Planning Bar Chart/CPM/ S-Curve Earned Value Control Santi Charoenpornpattana, Ph.D. @2009
What is “Scheduling” • “the function of arranging and sequencing the planned activities in order to achieving the objectives” • Questions to be answered: • What is the total duration of the project? • What are the start and finish dates for the activities? • Can a project activity be delayed? How long? Santi Charoenpornpattana, Ph.D. @2009
Real life example • It’s now 8.30 am. • You want to know the earliest time you can finish personal task for the lecture today: • Take a bath (5 min) • Dress up (5 min) • Boil water for tea (10 min) • Food reheat (5 min) • Eat breakfast (10 min) • Having tea (5 min) • Walk to lecture room (5 min) • Can you be on time for the class? If not, what should I do? • What is the earliest time you could reach the class? • How much free time do you have before the class? • Can I have any break after each task? Santi Charoenpornpattana, Ph.D. @2009
Planning Process 1 2 5 DESCRIP OF WORK “HOW” OBJECTIVES LOGICAL SEQUENCE AND RESOURCE REQUIREMENTS 7 PROJECT ORGANIZATION BUDGET MANPOWER 4 SCHEDULE “WHO” 3 WORK PLAN “WHAT” SCOPE OF WORK 6 PROJECT OBJECTIVES “HOW MUCH” “WHO DOES WHAT” “WHEN” WORK PACKAGE DESCRIPTION WORK BREAKDOWN STRUCTURE PROJECT BASE PLAN WORK SCHEDULE Source: lecture note Dr. ChotchaiCharoenngam, CE70.21 Integrated Project Planning and Control School of Engineering and Technology, AIT - 2008 SantiCharoenpornpattana, Ph.D. @2009
Typical Scheduling techniques • Bar Chart • Network Diagram Santi Charoenpornpattana, Ph.D. @2009
Categorizing scheduling techniques Santi Charoenpornpattana, Ph.D. @2009
Bar Chart Santi Charoenpornpattana, Ph.D. @2009
Barchart • Henry L. Gantt, World War I -1917 • Classic technique & Well known Pro: • Easy, Very effective communication tool • Very popular for representation of simpler schedules • Understandable to all level of management Con: • Can be complex when have >100 activities • Key shortcoming: No dependencies captured • Most effective as reporting format rather than representation Santi Charoenpornpattana, Ph.D. @2009
Bar Chart – construction phase ACTIVITIES Foundation Structural Architectural M & E Landscape TIME jan mar may feb april june july dec Santi Charoenpornpattana, Ph.D. @2009
Bar Chart – whole development Santi Charoenpornpattana, Ph.D. @2009
Hierarchy of Bar Charts Santi Charoenpornpattana, Ph.D. @2009
Network Diagram Santi Charoenpornpattana, Ph.D. @2009
Network Diagram • Shows not only timing but also interrelations and dependencies of the activities • Logical sequencebehind the activities are important • Two main types of network diagram • CPM (Critical Path Method) • PERT (Program Evaluation Review Technique) Activity 1 Activity 2 Activity 3 E C A B D Activity 4 Activity 5 Santi Charoenpornpattana, Ph.D. @2009
CPM • Standard scheduling technique in construction industry • Logical sequence is the key • Embedded in all commercial scheduling software (MS Project, Primavera Project Planner, etc) • Very effective for control purpose • Specified in the contract of almost all medium to large scale projects as a rule especially for the processes of change order and dispute resolution Santi Charoenpornpattana, Ph.D. @2009
Two ways of representing CPM • Arrow diagramming • Precedence diagramming Formwork procurement Formwork & Concrete Erecting steel Laying out footings Excavating footings Mobilizing 1 2 3 4 5 6 Steel procurement Formwork procurement Mobilizing Laying out footings Excavating footings Formwork & concrete Erecting steel Steel procurement Santi Charoenpornpattana, Ph.D. @2009
Steps in CPM scheduling Identifying activities Assigning logical interrelationships between activities Assigning duration for activities Calculation Santi Charoenpornpattana, Ph.D. @2009
1. Identifying activities • Breaking down project’s work into smaller elements • Work Breakdown Structure (WBS) Santi Charoenpornpattana, Ph.D. @2009
Templates Santi Charoenpornpattana, Ph.D. @2009
Example 1 WBS of house construction Santi Charoenpornpattana, Ph.D. @2009
Example 2 WBS of large scale building construction Santi Charoenpornpattana, Ph.D. @2009
Numbering Santi Charoenpornpattana, Ph.D. @2009
How many level ? • Until the manageable level • Until there is no important constraints between sub-activities • For small to medium construction work, 4-5 levels would be appropriate • For large-scale project, multiple-linked WBS are used. (Master WBS, GC WBS, SC WBS, etc.) Each is done by different party. Santi Charoenpornpattana, Ph.D. @2009
2. Logical interrelationships • Time-sequence relationships among the various activities • Mandatory – technical constraint • Foundation before structure • Excavation beforebackfilling • Discretionary – management constraint • Resource limitation • Organization policy/procedure • External – external constraint • Seasonal condition • Law and regulations Santi Charoenpornpattana, Ph.D. @2009
Example 3 D Arrow diagram B A dummy arrow F 1 2 5 6 C E 4 Precedence diagram B D F A C E Santi Charoenpornpattana, Ph.D. @2009
Quiz Santi Charoenpornpattana, Ph.D. @2009
Answer Found Struc Floor Rough Excav Finishing Base Rafter Roof Wall Clean Landscape Santi Charoenpornpattana, Ph.D. @2009
Arrow vs Precedence diagramming Santi Charoenpornpattana, Ph.D. @2009
Arrow vs Precedence diagramming Santi Charoenpornpattana, Ph.D. @2009
3. Duration • Amount of time assigned to complete a particular activity • How to determine? • Historical information • Information from subcontractor • Handbook • Duration = Work Quantity Crew production rate Santi Charoenpornpattana, Ph.D. @2009
4. Calculation • Forward & Backward calculation • The questions: • What is the total duration of the project? • What are the start and finish dates for the activities? • Can a project activity be delayed? How long? Santi Charoenpornpattana, Ph.D. @2009
Notations Early start Early finish Activity description j i Duration Total float Late start Late finish Activity Description Early start Early finish Duration Late start Late finish Total float Santi Charoenpornpattana, Ph.D. @2009
Forward pass 0 3 3 7 A B 2 3 1 3 TF 4 TF LF LS LS LF EF = ES + D B A 3 3 0 4 3 7 LS LS LF LF TF TF ES EF EF ES Santi Charoenpornpattana, Ph.D. @2009
Backward pass 0 3 3 7 A B 2 3 1 3 TF 4 TF LF is assigned or obtained 3 1 3 7 B A 3 3 0 4 3 7 LS = LF - D TF = LF – D – ES 3 0 7 3 0 0 EF ES EF ES Santi Charoenpornpattana, Ph.D. @2009
What is “Float” • Float or slack of activity is a measure of flexibility, or inherent surplus time in the activity’s scheduling • It indicates how long the activity can be delayed or extended without having effect on completion of the whole (or part) project Santi Charoenpornpattana, Ph.D. @2009
Example analysis B 4 8 C 2 4 2 4 CRITICAL PATH 2 4 4 8 0 0 A F 2 10 0 8 2 2 D E 3 5 0 8 2 3 2 10 1 2 0 0 5 6 6 8 3 3 Santi Charoenpornpattana, Ph.D. @2009
What the “critical path” can tell? • The path is critical ! • No delay is allowed in the path • Management must take special care on all activities along the critical path • Acceleration of the critical activities can shorten total project duration • Who cause delay ! Santi Charoenpornpattana, Ph.D. @2009
Quiz Santi Charoenpornpattana, Ph.D. @2009
B A A B A B B A EF EF EF EF EF EF EF EF ES ES ES ES ES ES ES ES D D D D D D D D LS LS LS LS LS LS LS LS LF LF LF LF LF LF LF LF Logical relationships • Four logical relationships: 2. Start-to-Start (SS) 1. Finish-to-Start (FS) Can start B only when A started Can start B only when A finished 4. Start-to-Finish (SF) 3. Finish-to-Finish (FF) Can finish B only when A finished Can finish B only when A started Santi Charoenpornpattana, Ph.D. @2009
B B A A A B A B EF EF EF EF EF EF EF EF ES ES ES ES ES ES ES ES D D D D D D D D LS LS LS LS LS LS LS LS LF LF LF LF LF LF LF LF Lag • Waiting duration before beginning of the subsequent action 2 7 3 5 Santi Charoenpornpattana, Ph.D. @2009
0 3 4 5 6 7 8 1 2 6 2 6 4 4 2 Excav Excav 2 Conc Conc 2 Excav 1 Conc 1 Use of SF SS FF and Lag • Excavation takes 6 days • Concrete takes 6 days • Concrete can be started after excavation is already started for 2 days • Concrete can be finished after excavation is already finished for 2 days Excavation Concrete 2 2 Santi Charoenpornpattana, Ph.D. @2009
F H G I E D C B J A K EF EF EF EF EF EF EF EF EF EF EF ES ES ES ES ES ES ES ES ES ES ES 6 0 2 0 6 2 3 4 2 3 4 LS LS LS LS LS LS LS LS LS LS LS LF LF LF LF LF LF LF LF LF LF LF Calculation of PDM 1 3 1 2 Santi Charoenpornpattana, Ph.D. @2009
E A I B C H D J G F K 2 2 0 0 3 6 2 4 6 3 4 Calculation of PDM 1 3 1 2 Santi Charoenpornpattana, Ph.D. @2009
F C I G 8 4 15 12 12 6 0 4 6 4 4 3 5 8 1 14 14 17 5 9 Calculation of PDM B D 3 6 0 4 3 2 1 0 4 3 6 3 E H J K 9 15 17 17 4 9 15 17 2 6 2 0 A 0 0 0 7 9 15 17 9 15 17 17 0 0 1 2 Santi Charoenpornpattana, Ph.D. @2009
Quiz Santi Charoenpornpattana, Ph.D. @2009
Float Santi Charoenpornpattana, Ph.D. @2009