t.l. martin & associates copyright © 2008 chapter 1 fundamentals of scheduling t.l. martin...
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T.L. Martin & AssociatesT.L. Martin & Associates
Copyright © 2008Copyright © 2008
Chapter 1Chapter 1Fundamentals of SchedulingFundamentals of Scheduling
T.L. Martin & Associates, Inc.18552 Office Park Drive
Gaithersburg, Maryland 20886Phone (240) 632-1710 & FAX (240) 632-1712
e-mail: [email protected]
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The FundamentalsThe Fundamentals
• The primary goal of a schedule is to manage time.
• A plan is an order of work.
• When time frames are applied to a plan, a schedule is created.
• Critical Path Method is used to forecast when work activities are to take place.
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When to Use a CPMWhen to Use a CPM
• A CPM is used when the scope of work of a project becomes complex.
• A bar chart can not capture the many relationships between activities in a complex project.
• Rule of thumb - any project with over forty (40) definable tasks.
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Why Use a CPM ScheduleWhy Use a CPM Schedule
• Contractor is responsible for planning, scheduling and progressing the work.
• An Owner and its representatives must assure that the contractor meets its obligations.
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Why Use a CPM ScheduleWhy Use a CPM Schedule
• If a contractor fails:– Then an Owner may withhold progress
payments – or default terminate the contractor.
• The schedule is vital.
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Bar Chart SchedulesBar Chart Schedules
• The bar chart is an excellent tool.
• Work tasks or activities are shown as bars across a horizontal calendar.
• If a bar chart is prepared carefully, the planner logically times the work based on:– physical restraints– contractual restraints– realistic use of men and equipment.
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Bar Chart ScheduleBar Chart ScheduleFoundation Project Bar Chart
Description 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Excavate
Form Ftg & Slab
Place Rebar
Install MEP Rough-In
Inspect & Pour
Review FND Design
Special PM
Scheduled Periods
Bars Indicate When in Time a Work Task is Planned to be Performed.
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Bar Chart ScheduleBar Chart Schedule
• A bar chart can include budgets versus actual. • Tasks or activities are resource loaded across
the horizontal calendar.• This allows a real-time view of budget versus
actual highlighting any problems of selected important project components such as: – manpower - costs– equipment - revenue– cash flow - material– activity timing (ahead or behind plan)
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Bar Chart ScheduleBar Chart ScheduleFoundation Project Bar Chart
Description Quantity UMMan-Hours
$ x $1,000
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Excavate 250 cyMan-Hours 270 90 90 90
Cost $4.2Form Ftg & Slab 1,600 csf
Man-Hours 180 60 60 60Cost $3.6
Place Rebar 5 tonMan-Hours 60 20 20 20
Cost $3.3Install MEP Rough-In 1 ls
Man-Hours 120 40 40 40Cost $6.0
Inspect & Pour 100 cyMan-Hours 90 30 30 30
Cost $2.7Review FND Design 1 ls
Man-Hours 10 5 5Cost $0.8
Special PM 1 lsMan-Hours 48 8 8 8 8 8 8
Cost $3.0
Man-Hours 778 90 95 95 68 68 68 28 28 28 40 40 40 30 30 30$ x 1,000 $23.6Man-Hours 90 185 280 348 416 484 512 540 568 608 648 688 718 748 778$ x 1,000
Man-Hours 78 117 150 234 312$ x 1,000
Scheduled Periods
Daily Total
Cumulative Total
Actual To Date
Add Planned Resources, Spread to Time Periods of Performance, Sum Total of All Tasks for Each Period.
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Bar Chart ScheduleBar Chart ScheduleFoundation Project Bar Chart
Description Quantity UMMan-Hours
$ x $1,000
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15Tot
Total Man-Hours
Excavate 250 cy 780Man-Hours 270 90 90 90 741
Cost $4.2 702Form Ftg & Slab 1,600 csf 663
Man-Hours 180 60 60 60 624Cost $3.6 585
Place Rebar 5 ton 546Man-Hours 60 20 20 20 507
Cost $3.3 468Install MEP Rough-In 1 ls 429
Man-Hours 120 40 40 40 390Cost $6.0 351
Inspect & Pour 100 cy 312Man-Hours 90 30 30 30 273
Cost $2.7 234Review FND Design 1 ls 195
Man-Hours 10 5 5 156Cost $0.8 117
Special PM 1 ls 78Man-Hours 48 8 8 8 8 8 8 39
Cost $3.0 0
Man-Hours 778 90 95 95 68 68 68 28 28 28 40 40 40 30 30 30$ x 1,000 $23.6Man-Hours 90 185 280 348 416 484 512 540 568 608 648 688 718 748 778$ x 1,000
Man-Hours 78 117 150 234 312$ x 1,000
Scheduled Periods
Daily Total
Cumulative Total
Actual To Date
Man-Hours
Planned versus Actual Can be Compared.
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Bar Chart ScheduleBar Chart ScheduleFoundation Project Bar Chart
Description Quantity UMMan-Hours
$ x $1,000
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15Total Cost X $1,000
Excavate 250 cy $28.0Man-Hours 270 90 90 90 $26.6
Cost $4.2 1.4 1.4 1.4 $25.2Form Ftg & Slab 1,600 csf $23.8
Man-Hours 180 60 60 60 $22.4Cost $3.6 1.2 1.2 1.2 $21.0
Place Rebar 5 ton $19.6Man-Hours 60 20 20 20 $18.2
Dollars $3.3 1.1 1.1 1.1 $16.8Install MEP Rough-In 1 ls $15.4
Man-Hours 120 40 40 40 $14.0Cost $6.0 2 2 2 $12.6
Inspect & Pour 100 cy $11.2Man-Hours 90 30 30 30 $9.8
Cost $2.7 0.9 0.9 0.9 $8.4Review FND Design 1 ls $7.0
Man-Hours 10 5 5 $5.6Cost $0.8 0.4 0.4 $4.2
Special PM 1 ls $2.8Man-Hours 48 8 8 8 8 8 8 $1.4
Cost $3.0 0.5 0.5 0.5 0.5 0.5 0.5 $0.0
Man-Hours 778 90 95 95 68 68 68 28 28 28 40 40 40 30 30 30Dollars x 1,000 $23.6 1.4 1.8 1.8 1.7 1.7 1.7 1.6 1.6 1.6 2 2 2 0.9 0.9 0.9Man-Hours 90 185 280 348 416 484 512 540 568 608 648 688 718 748 778$ x 1,000 1.4 3.2 5.0 6.7 8.4 10.1 11.7 13.3 14.9 16.9 18.9 20.9 21.8 22.7 23.6
Man-Hours 78 117 150 234 312$ x 1,000 1 1.4 2.8 4.2 5.6
Scheduled Periods
Daily Total
Cumulative Total
Actual To Date
Cost
Planned versus Actual Costs Can be Compared.
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Bar Chart ScheduleBar Chart ScheduleFoundation Project Bar Chart
Description Quantity UMMan-Hours
$ x $1,000
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15Total Cost X $1,000
Total Man-Hours
Excavate 250 cy $28.0 780Man-Hours 270 90 90 90 $26.6 741
Cost $4.2 1.4 1.4 1.4 $25.2 702Form Ftg & Slab 1,600 csf $23.8 663
Man-Hours 180 60 60 60 $22.4 624Cost $3.6 1.2 1.2 1.2 $21.0 585
Place Rebar 5 ton $19.6 546Man-Hours 60 20 20 20 $18.2 507
Cost $3.3 1.1 1.1 1.1 $16.8 468Install MEP Rough-In 1 ls $15.4 429
Man-Hours 120 40 40 40 $14.0 390Cost $6.0 2 2 2 $12.6 351
Inspect & Pour 100 cy $11.2 312Man-Hours 90 30 30 30 $9.8 273
Cost $2.7 0.9 0.9 0.9 $8.4 234Review FND Design 1 ls $7.0 195
Man-Hours 10 5 5 $5.6 156Cost $0.8 0.4 0.4 $4.2 117
Special PM 1 ls $2.8 78Man-Hours 48 8 8 8 8 8 8 $1.4 39
Cost $3.0 0.5 0.5 0.5 0.5 0.5 0.5 $0.0 0
Man-Hours 778 90 95 95 68 68 68 28 28 28 40 40 40 30 30 30$ x 1,000 $23.6 1.4 1.8 1.8 1.7 1.7 1.7 1.6 1.6 1.6 2 2 2 0.9 0.9 0.9Man-Hours 90 185 280 348 416 484 512 540 568 608 648 688 718 748 778$ x 1,000 1.4 3.2 5.0 6.7 8.4 10.1 11.7 13.3 14.9 16.9 18.9 20.9 21.8 22.7 23.6
Man-Hours 78 117 150 234 312$ x 1,000 1 1.4 2.8 4.2 5.6
Scheduled Periods
Daily Total
Cumulative Total
Actual To Date
Man-Hours
Cost
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Bar Chart ScheduleBar Chart Schedule
• A bar chart can include important budgets versus actual recorded for each Task.
• The Bar Chart May become Crowded. It is important to Select the Most Meaningful project components to Monitor.
• The following Bar Chart is an Example which Monitors:– Man-Hours - Costs - Revenue
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Foundation Project Bar Chart
Description Quantity UMMan-Hours
$ x 1,000 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15900 MH
Excavate 250 cyActual To Date 300 cyMan-Hours 270 90 90 90
Actual To Date 178 89 89 800 MHCost $4.20 $1.40 $1.40 $1.40
Actual To Date $3.00 $1.50 $1.50Revenue $5.29 $1.76 $1.76 $1.76
Actual To Date $5.29 $2.65 $2.65
Form Ftg & Slab 1,600 csf
Actual To Date 1,000 csf 700 MHMan-Hours 180 60 60 60
Actual To Date 125 25 50 50Cost $3.60 $1.20 $1.20 $1.20
Actual To Date $2.50 $0.50 $1.00 $1.00Revenue $4.54 $1.51 $1.51 $1.51
Actual To Date $2.84 $0.57 $1.13 $1.13 600 MH
Place Rebar 5 ton
Actual To Date
Man-Hours 60 20 20 20Actual To Date
Cost $3.30 $1.10 $1.10 $1.10Actual To Date 500 MH
Revenue $4.16 $1.39 $1.39 $1.39Actual To Date
Install MEP Rough-In 1 ls
Actual To Date
Man-Hours 120 40 40 40Actual To Date 400 MH
Cost $6.00 $2.00 $2.00 $2.00Actual To Date
Revenue $7.56 $2.52 $2.52 $2.52Actual To Date
Inspect & Pour 100 cy
Actual To Date 300 MHMan-Hours 90 30 30 30
Actual To Date
Cost $2.70 $0.90 $0.90 $0.90Actual To Date
Revenue $3.40 $1.13 $1.13 $1.13Actual To Date
Review FND Design 1 ls 200 MH
Actual To Date 100% %Man-Hours 10 5 5
Actual To Date 8 4 4Cost $0.80 $0.40 $0.40
Actual To Date $0.64 $0.32 $0.32Revenue $1.01 $0.50 $0.50 100 MH
Actual To Date $1.01 $0.50 $0.50
Project Management 15 Periods
Actual To Date 5 PeriodsMan-Hours 120 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8
Actual To Date 40 8 8 8 8 8Cost $9.00 $0.60 $0.60 $0.60 $0.60 $0.60 $0.60 $0.60 $0.60 $0.60 $0.60 $0.60 $0.60 $0.60 $0.60 $0.60 0 MH
Actual To Date $2.55 $0.51 $0.51 $0.51 $0.51 $0.51Revenue $11.34 $0.76 $0.76 $0.76 $0.76 $0.76 $0.76 $0.76 $0.76 $0.76 $0.76 $0.76 $0.76 $0.76 $0.76 $0.76
Actual To Date $3.78 $0.76 $0.76 $0.76 $0.76 $0.76
Man-Hours 98 201 304 372 440 508 536 564 592 640 688 736 774 812 850Cost $ x 1,000 $2.00 $4.40 $6.80 $8.60 $10.40 $12.20 $13.90 $15.60 $17.30 $19.90 $22.50 $25.10 $26.60 $28.10 $29.60Revenue $ x 1,000 $2.52 $5.54 $8.57 $10.84 $13.10 $15.37 $17.51 $19.66 $21.80 $25.07 $28.35 $31.63 $33.52 $35.41 $37.30
Man-Hours 97 198 235 293 351 Cost $ x 1,000 $2.01 $4.34 $5.67 $7.18 $8.69 Revenue $ x 1,000 $3.40 $7.31 $9.14 $11.03 $12.92
Scheduled Periods
Planned Cumulative Total
Actual Cumulative Total
Da
ta D
ate
0
1 0 0
2 0 0
3 0 0
4 0 0
5 0 0
6 0 0
7 0 0
8 0 0
9 0 0
1 2 3 4 5 6 7 8 9 1 0 1 1 1 2 1 3 1 4 1 5
$0.00
$5.00
$10.00
$15.00
$20.00
$25.00
$30.00
$35.00
$40.00
$ x
1,00
0
Planned Cumulative Total Man-Hours
Actual Cumulative Total Man-Hours
Planned Cumulative Total Cost $ x 1,000
Planned Cumulative Total Revenue $ x 1,000
Actual Cumulative Total Cost $ x 1,000
Actual Cumulative Total Revenue $ x 1,000
Budget Revenue is Close to Actual Revenue, Thus Project is on Time
Both Man-Hours and Costs are Less than Budgeted, Thus Project so Far is a Winner.
Note Actual Timing, Man-Hours, Cost and Earned Revenue are Recorded and Compared with Budgets.
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Bar Chart SchedulesBar Chart Schedules
• Bar chart does not include logic lines.
• More complex Projects require interrelated activities.
• A simple bar chart cannot capture the many relationships and interdependencies between activities on complex projects.
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The CPM ScheduleThe CPM Schedule
• CPM requires the detailed planning and scheduling of all elements of a project, from start to completion.
• CPM results in a network of tasks of:– Defined duration,– Tied together by physical, contractual and
selected optional relationships.
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Critical Path Method ScheduleCritical Path Method Schedule
5
5
5
5
52
S S S S S S S SM T W T F M T W T F M T W T F M T W T F
Excavate
Place Rebar
Install MEPRough In
10
InspectFND
Review/Approve FNDDesign
Inspect andPour
Form Footing& Slab
The standard Finish-Start relationship. An Activity Finishes so Following Activity can Start.
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The CPM ScheduleThe CPM Schedule• Once a network of activities has been
created, task start and finish dates can be computed.
• The longest activity chain, from the start of the project to its completion, is termed the projects Critical Path.
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The CPM ScheduleThe CPM Schedule
• An activity or task is:– definable– must be accomplished
• The activity includes:– duration– linked to other activities
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The CPM ScheduleThe CPM Schedule• Budget Resources, Costs and Revenue
may be assigned to each Network activity.
• After the CPM is created it can be updated with current project information. – Actual Timing: Start, % Complete, Finish– Resources Used
• Man-Hours ● Equipment-Hours • Material Quantities ● Costs • Other Components
• Monitor Budgets versus Actual Timely.
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The CPM Schedule - RelationshipsThe CPM Schedule - Relationships
• Physical dependence and requirements between activities generally can not be changed. – One work element builds on a previous one. – Site constraints – Special weather considerations
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• Contractual requirements:– Owner imposed phasing of the work. – Permitting issues, – Owner furnished equipment,– Land procurement, – Early turnover of certain areas of the project.
The CPM Schedule - RelationshipsThe CPM Schedule - Relationships
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The CPM Schedule - RelationshipsThe CPM Schedule - Relationships
• Physical and contractual requirements are rigid.
• Activity relationships based on contractor options are far more flexible. – Manpower– Equipment – Contractor’s approach to the project, the
contractor’s “means and methods.”
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Please Proceed to Please Proceed to Chapter 2 Chapter 2 Key CPM Scheduling TermsKey CPM Scheduling Terms