ence 667 project performance measurement · ence 667 project performance measurement patuxent water...
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ENCE 667Project Performance
MeasurementPatuxent Water Treatment Plant
Upgrade schedule analysis
Presented by:Luis Rubio
Isobo Tariah
Project Overview
• Location: Laurel, Maryland• Total Cost: $45 million• Capacity: 56 MGD• Owner: Washington Suburban Sanitary
Commission• Contractor: Danis Environmental
Industries• Phases: Stage I & Stage II
Stage I• Demolition of Filter Unit 1• Construction of 3 treatment trains
– Flocculation Basin– Sedimentation Basin– Chlorine contact chamber– Deep bed filters– Backwash tank– Chemical feed system
• Duration: 385 working days
Stage I Existing Filter Unit
Stage I Demolition of Filter Unit
Stage I Construction of new process structure
Stage II
• Demolition of Filter Unit 2, 3 & 4• Construction of 2 treatment trains
– Flocculation Basin– Sedimentation Basin– Chlorine contact chamber– Deep bed filters– Backwash tank– Chemical feed system
• Duration: 650 working days
Purpose of the Upgrade• Save $24 Million using High-rate
processes– Static Mixers for rapid mixing– Four-stage tapered-energy flocculation
shaft– Sedimentation plate settlers– Granular activated carbon– Sand filters with air backwash
• Capable to run at 72-80 MGD in emergency situation
Project Objectives
• To complete Stage I at the minimum time/cost tradeoff.– Develop a CPM schedule– Determine Critical Path– Crash activities in the critical path– Estimate cost associated with crashing
Project Performance Measurement Concepts Used
• CPM Schedule• Gantt Chart• Linear Programming
– Minimize project cost – Obtain optimal crashing time
• Time/Cost trade-off curve
Project ActivitiesID Task Name Duration Predecessors3 Mobilization 10 -4 Process Testing 5 557 Soil Erosion Control 10 38 Install temp 16" Hs Line 8 711 Excavation for new treatment trains 15 2928 Shut down existing filter unit #1 4 829 Demolish existing filter unit #1 36 2831 Flocculation bsin bsae slab 27 1132 Sedimentation basin base slab 29 3133 Chlorine contct chamber base slab 28 3234 Filter / Filter gallery base slab 43 3338 Filter / Filter gallery lower slab 50 3445 Filtr control gallery slab 12 3847 Backwash tank slab 20 4848 Backwash tank walls 10 4555 Process tank water-lear test 5 8174 Install backwash drain valve 6 7979 Install backwash piping 30 4781 Install Control System / Electrical rough-in 90 74
Project Schedule
AOA Diagram Original
ST A B C D E
I J K L H
G F
M N O
P Q R END
103 7 8 28 29 11 31
33 34 38 45 48 47 79
32
74
81 55 4
10 8 4 36 15 27
29
28 43 50 12 10 20 30
6
5 590
0 0 10 10 2020 28 28 32 32 6868 83 83 110 110
139 139 167 167 210 210 260 260 272 272 282 282 302 302 332 332
338338 428 428 433 433 438 438
Project Crashing
• Estimated duration: 438 days• Contractual required date: 385 days• Difference: 53 days• Penalty: $12,775 per day• Bonus: $4,000 per day
Project Crashing
ActivityOriginal Duration
Max. Crash duration
Cost per crash unit
3 10 2 8,000.00$ 4 5 1 5,500.00$ 7 10 1 8,000.00$ 8 8 3 13,500.00$
11 15 3 16,800.00$ 28 4 0 12,000.00$ 29 36 5 14,500.00$ 31 27 5 7,500.00$ 32 29 5 14,000.00$ 33 28 2 5,000.00$ 34 43 8 13,500.00$ 38 50 9 15,850.00$ 45 12 1 10,000.00$ 47 20 3 5,500.00$ 48 10 1 4,000.00$ 55 5 1 9,500.00$ 74 6 1 11,500.00$ 79 30 4 7,500.00$ 81 90 10 10,000.00$
Penalty/Bonus
$(100,000)
$-
$100,000
$200,000
$300,000
$400,000
$500,000
$600,000
$700,000
373 378 383 388 393 398 403 408 413 418 423 428 433 438
Duration
Cos
t
Penalty / Bonus
$268,275
406
Crashing Cost
$-
$100,000
$200,000
$300,000
$400,000
$500,000
$600,000
$700,000
$800,000
373 378 383 388 393 398 403 408 413 418 423 428 433 438
Duration
Cost
Crashing Cost
$258,500
406
Project Crashing For optimal duration (406 days)
ActivityOriginal Duration
Max. Crash duration
Crash duration
Cost per crash unit Crashing Cost
3 10 2 2 8,000.00$ 16,000.00$ 4 5 1 1 5,500.00$ 5,500.00$ 7 10 1 1 8,000.00$ 8,000.00$ 8 8 3 13,500.00$ -$
11 15 3 16,800.00$ -$ 28 4 0 12,000.00$ -$ 29 36 5 14,500.00$ -$ 31 27 5 5 7,500.00$ 37,500.00$ 32 29 5 14,000.00$ -$ 33 28 2 2 5,000.00$ 10,000.00$ 34 43 8 13,500.00$ -$ 38 50 9 15,850.00$ -$ 45 12 1 1 10,000.00$ 10,000.00$ 47 20 3 3 5,500.00$ 16,500.00$ 48 10 1 1 4,000.00$ 4,000.00$ 55 5 1 1 9,500.00$ 9,500.00$ 74 6 1 1 11,500.00$ 11,500.00$ 79 30 4 4 7,500.00$ 30,000.00$ 81 90 10 10 10,000.00$ 100,000.00$
Total 438 65 32 258,500.00$
Sensitivity Analysis
$500,000
$550,000
$600,000
$650,000
$700,000
$750,000
373 378 383 388 393 398 403 408 413 418 423 428 433 438
Duration
Tota
l Cos
t
Total Cost
$526,775
406
Total cost = Crashing Cost + Penalty/Bonus
Total cost = $258,500 + $268,275 = $526,775
AOA Diagram Original – Crashed
ST A B C D E
I J K L H
G F
M N O
P Q R END
83 7 8 28 29 11 31
33 34 38 45 48 47 79
32
74
81 55 4
9 8 4 36 15 22
29
26 43 50 11 9 17 26
5
4 480
0 0 8 8 1717 25 25 29 29 6565 80 80 102 102
131 131 157 157 200 200 250 250 261 261 270 270 287 287 313 313
318318 398 398 402 402 406 406
Schedule Alternative
• Some activities relations were changed in order to have parallel activities.
• Possible changes in the critical path.• Estimated duration should decrease.• Crashing: 53 days less than the
estimated duration.
Project Schedule
AOA Diagram Alternative
ST A
B
C
D
E G
H
I
J
F
K M
103 7
8 28
29
11 31
33
34
38
45 48
47
79
32
7481 55 4
10
8 4
36
15 27
29 28
43
50
12 10
20
30
6 5 590
L
O END N
0 0 10 10 2222 6464 93 93 121 121
164 164
176 176 264 264
214 214 234234 324324 330330 335335 340 340
Project Crashing For contractual date (287 days)
ActivityOriginal Duration
Max. Crash duration
Crash duration
Cost per crash unit Crashing Cost
3 10 2 2 8,000.00$ 16,000.00$ 4 5 1 1 5,500.00$ 5,500.00$ 7 10 1 1 8,000.00$ 8,000.00$ 8 8 3 3 13,500.00$ 40,500.00$
11 15 3 3 16,800.00$ 50,400.00$ 28 4 0 12,000.00$ -$ 29 36 5 2 14,500.00$ 29,000.00$ 31 27 5 5 7,500.00$ 37,500.00$ 32 29 5 5 14,000.00$ 70,000.00$ 33 28 2 2 5,000.00$ 10,000.00$ 34 43 8 8 13,500.00$ 108,000.00$ 38 50 9 9 15,850.00$ 142,650.00$ 45 12 1 10,000.00$ -$ 47 20 3 3 5,500.00$ 16,500.00$ 48 10 1 4,000.00$ -$ 55 5 1 1 9,500.00$ 9,500.00$ 74 6 1 1 11,500.00$ 11,500.00$ 79 30 4 7,500.00$ -$ 81 90 10 10 10,000.00$ 100,000.00$
Total 56 655,050.00$
Contractual date = Estimated duration - 53 days = 287 days
Penalty/Bonus
$-
$100,000
$200,000
$300,000
$400,000
$500,000
$600,000
$700,000
$800,000
287 292 297 302 307 312 317 322 327 332 337
Duration
Cos
t
Penalty / Bonus
$357,700
315
Crashing Cost
$-
$100,000
$200,000
$300,000
$400,000
$500,000
$600,000
$700,000
287 292 297 302 307 312 317 322 327 332 337
Duration
Cost
Crashing Cost
$206,500
315
Sensitivity Analysis
$550,000
$575,000
$600,000
$625,000
$650,000
$675,000
$700,000
287 292 297 302 307 312 317 322 327 332 337
Duration
Tota
l Cos
t
Total Cost
$564,200
Total cost = Crashing Cost + Penalty/Bonus
Total cost = $206,500 + $357,700 = $564,200
315
Project Crashing For optimal duration (315 days)
ActivityOriginal Duration
Max. Crash duration
Crash duration
Cost per crash unit Crashing Cost
3 10 2 2 8,000.00$ 16,000.00$ 4 5 1 1 5,500.00$ 5,500.00$ 7 10 1 8,000.00$ -$ 8 8 3 13,500.00$ -$
11 15 3 16,800.00$ -$ 28 4 0 12,000.00$ -$ 29 36 5 14,500.00$ -$ 31 27 5 5 7,500.00$ 37,500.00$ 32 29 5 14,000.00$ -$ 33 28 2 2 5,000.00$ 10,000.00$ 34 43 8 13,500.00$ -$ 38 50 9 15,850.00$ -$ 45 12 1 10,000.00$ -$ 47 20 3 3 5,500.00$ 16,500.00$ 48 10 1 4,000.00$ -$ 55 5 1 1 9,500.00$ 9,500.00$ 74 6 1 1 11,500.00$ 11,500.00$ 79 30 4 7,500.00$ -$ 81 90 10 10 10,000.00$ 100,000.00$
Total 25 206,500.00$
AOA Diagram Alternative – Crashed
ST A
B
C
D
E G
H
I
J
F
K M
83 7
8 28
29
11 31
33
34
38
45 48
47
79
32
7481 55 4
10
8 4
36
15 22
29 26
43
50
12 10
17
30
5 4 480
L
O END
N
0 0 8 8 2020
16 16 35 35
57 57 86 86 112 112
155 155
167 195 252 302
205 205 222222 302302 307307 311 311 316 316
Conclusions
• Optimal duration should be 406 days– Cost: $526,775
• When estimating the project bid, scheduling analysis should be perform to evaluate the necessity of crashing the project. If that is the case, the cost should be included in the bid.
Future Extensions
• PERT Analysis
• Limited resources allocation
Questions