A Technique for Selecting Appropriate Allowable Pile Loads for Driven-Pile Projects: Load Matching

A Technique for Selecting Appropriate Allowable Pile Loads for Driven-Pile Projects: Load Matching Pile Driving Contractors Association 2015 Professor s Driven Pile Institute June 25, 2015 Van E. Komurka, P.E., D.GE, F.ASCE Wagner Komurka Geotechnical Group, Inc. 1

Talk Outline Support Cost Define Pile Support Cost Based on Available Support Based on Utilized Support Load-Matching Evaluations Philosophy Define Optimum Allowable Pile Load Case Histories Medium/Large Small 2

Talk Outline Support Cost Define Pile Support Cost Based on Available Support Based on Utilized Support Load-Matching Evaluations Philosophy Define Optimum Allowable Pile Load Case Histories Medium/Large Small 3

Pile Support Cost: Design Efficiency Based on Available Support Installed Cost = $ 5,000 Allowable Pile Load = 250 T Based on Utilized Support Large Resisted Loads Small Resisted Loads Structure Design Load = 700 T Structure Design Load = 300 T $ 5,000 250 T $ 20.00 per available ton = 3 x $ 5,000 700 T = $ 21.43 per structure design ton 3 x $ 5,000 300 T = $ 50.00 per structure design ton 4

Talk Outline Support Cost Define Pile Support Cost Based on Available Support Based on Utilized Support Load-Matching Evaluations Philosophy Define Optimum Allowable Pile Load Case Histories Medium/Large Small 5

Load-Matching Evaluation Match Allowable Pile Loads to Column Loads! Piles are below-grade structural extensions of abovegrade structural elements; their design should be integrated with the above-grade design. Using one allowable pile load for a project is analogous to using one beam or column design throughout a building. Two fixed design components: Structural loads to support (column load schedule). Soil/pile resistance behavior to support structural loads (depth vs. capacity relationships). Deep foundation system design flexibility (choice of pile type, section, allowable load, construction-control method, safety factor, etc.) allows optimally matching fixed design components. 6

Talk Outline Support Cost Define Pile Support Cost Based on Available Support Based on Utilized Support Load-Matching Evaluations Philosophy Define Optimum Allowable Pile Load Case Histories Medium/Large Small 7

900 K Load Matching Evaluation Optimum Allowable Pile Load = Column Design Load Minimum Req d No. of Piles 8

Minimum Required Number of Piles Minimum 1 Pile Required? Minimum 2 Piles Required Minimum 3 Piles Required 9

900 K Optimum Allowable Pile Load = Column Design Load Minimum Req d No. of Piles Column Design Load = 900 kips Minimum Req d No. of Piles = 3 Optimum Allowable Pile Load = 900 kips 3 piles = 300 kips/pile = 150 tons/pile 10

Lower-Than-Optimum Allowable Pile Loads Increased pile support costs each ton of allowable pile load costs more than it would have with higherallowable-load piles. Increased cap support costs each cap is larger than it would have been with higher-allowable-load piles; may increase excavation/material disposal costs, utility relocation costs. Increased number of pile installations. May increase total project drive time, construction control monitoring costs. 11

Higher-Than-Optimum Allowable Pile Loads Unused capacity installed although pile support costs are low, and cap costs are minimized, unnecessary capacity is installed (unnecessary cost is incurred). 12

Talk Outline Support Cost Define Pile Support Cost Based on Available Support Based on Utilized Support Load-Matching Evaluations Philosophy Define Optimum Allowable Pile Load Case Histories Medium/Large Small 13

Load-Matching Design Approach Obtain foundation layout, column load schedule, and the minimum required number of piles at each cap, from structural engineer. Calculate optimum allowable pile load for each cap. If desired, calculate required ultimate pile capacity for each cap. To evaluate the cost-effectiveness of field testing, this can be done for a range of factors of safety. 14

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F.S. = 2.00 Maximum Optimum Required Allowable "Ultimate" Column Min. Column Pile Pile Line No. Load, Load, Capacity, Designation of Piles kips tons tons 0.A-8.5 1 158 79 158 0.A-0.5 1 180 90 180 P-3.3 1 181 91 181 P-3.7 1 181 91 181 P-4.5 1 181 91 181 P-5 1 181 91 181 P-5.5 1 181 91 181 P-6 1 181 91 181 0.A-8 1 203 102 203 M.5-8 1 228 114 228 N-8.5 1 360 180 360 P.7-8.5 1 360 180 360 P-0.5 1 360 180 360 P-8.5 1 360 180 360 Q.8-3 1 360 180 360 Q-0.5 1 360 180 360 M.5-4 1 368 184 368 J-5 2 748 187 374 G-7 3 1479 247 493 H-7 3 1479 247 493 K-6 3 1484 247 495 B-7 3 1487 248 496 B-6 3 1507 251 502 C-8 3 1508 251 503 R1-5.9 3 1510 252 503 K-7 3 1529 255 510 C-4 3 1874 312 625 F-6 3 1879 313 626 J-6 3 1942 324 647 J-4 3 1995 333 665 Q-9 3 2003 334 668 R-9 3 2003 334 668 448 17

Load-Matching Design Approach Obtain foundation layout, column load schedule, and an indication of the minimum required number of piles at each cap, from structural engineer. Calculate optimum allowable pile load for each cap. Calculate required ultimate pile capacity for each cap. To evaluate the cost-effectiveness of field testing, this can be done for a range of factors of safety. Generate histogram of optimum allowable pile loads. 18

Number of Piles 194 tons 180 tons 227 tons 91 tons Allowable Pile Load Histogram 70 60 50 40 30 20 10 0 75 100 125 150 175 200 225 250 275 300 325 350 375 Optimum Allowable Pile Load, tons 19

Load-Matching Design Approach Obtain foundation layout, column load schedule, and an indication of the minimum required number of piles at each cap, from structural engineer. Calculate optimum allowable pile load for each cap. Calculate required ultimate pile capacity for each cap. To evaluate the cost-effectiveness of field testing, this can be done for a range of factors of safety. Generate histogram of optimum allowable pile loads. Select appropriate allowable pile loads, with designteam input. 20

Number of Piles 194 tons 180 tons 227 tons 91 tons Allowable Pile Load Histogram 70 91 tons 180 tons 251 tons 60 50 40 30 20 10 0 75 100 125 150 175 200 225 250 275 300 325 350 375 Optimum Allowable Pile Load, tons 21

Number of Piles For Comparison - Different Case History 30 Number of Piles vs. Optimum Allowable Axial Compression Pile Load 25 20 48 Tons 113 Tons 15 10 5 0 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 Optimum Allowable Axial Compression Pile Load, tons 22

Load-Matching Design Approach (continued) Select viable pile type(s) and section(s) for selected allowable loads (91 T, 180 T, and 251 T ). {borings} Estimate individual pile lengths required for selected pile capacities. 23

Pile Toe Elevation, feet Estimated Ultimate Pile Capacity - Borings 13.375-Inch-Diameter Pipe Piles 10 0-10 -20-30 -40-50 -60-70 -80-90 -100-110 0 100 200 300 400 500 600 700 Estimated Ultimate Pile Capacity, tons 24

Pile Toe Elevation, feet 10 0-10 -20-30 -40-50 -60 EOID Capacity Set-Up Pile Test Program Results - -70-80 -90 Long-term Capacity Capacity Profiles -100-110 -120-130 0 50 100 150 200 250 300 350 Estimated Ultimate Capacity, tons 25

Load-Matching Design Approach (continued) Select viable pile type(s) and section(s) for selected allowable pile loads (91 T, 180 T, 251 T ). Estimate individual pile lengths required for selected pile capacities. Estimate total pile lengths required for project. Using representative prices, estimate total pile cost for project. 26

Number of Piles 194 tons 180 tons 227 tons 91 tons Allowable Pile Load Histogram 70 91 tons 180 tons 251 tons 60 50 40 30 20 10 0 75 100 125 150 175 200 225 250 275 300 325 350 375 Optimum Allowable Pile Load, tons 27

F.S. = 2.00 Maximum Optimum Required Allowable "Ultimate" 3 Capacities (91, 180, and 251 tons) Column Min. Column Pile Pile Est. Pile Est. Pile(s) Est. Pile(s) Line No. Load, Load, Capacity, No. Length, Footage, Cost, Designation of Piles kips tons tons of Piles feet feet dollars 0.A-8.5 1 158 79 158 1 62 62 1,340 0.A-0.5 1 180 90 180 1 62 62 1,340 $21.61 / ft P-3.3 1 181 91 181 1 62 62 1,340 91-ton max. P-3.7 1 181 91 181 1 62 62 1,340 allow. load: P-4.5 1 181 91 181 1 62 62 1,340 71 P-5 1 181 91 181 1 62 62 1,340 10.75x0.365 P-5.5 1 181 91 181 1 62 62 1,340 feet: P-6 1 181 91 181 1 62 62 1,340 4,402 0.A-8 1 203 102 203 1 86 86 2,405 M.5-8 1 228 114 228 1 86 86 2,405 $27.97 / ft N-8.5 1 360 180 360 1 86 86 2,405 180-ton max. P.7-8.5 1 360 180 360 1 86 86 2,405 allow. load: P-0.5 1 360 180 360 1 86 86 2,405 108 P-8.5 1 360 180 360 1 86 86 2,405 13-3/8" 0.480 Q.8-3 1 360 180 360 1 86 86 2,405 feet: Q-0.5 1 360 180 360 1 86 86 2,405 9,288 M.5-4 1 368 184 368 1 95 95 2,657 J-5 2 748 187 374 2 95 190 5,314 G-7 3 1479 247 493 3 95 285 7,971 251-ton max. H-7 3 1479 247 493 3 95 285 7,971 allow. load: K-6 3 1484 247 495 3 95 285 7,971 177 B-7 3 1487 248 496 3 95 285 7,971 13-3/8" 0.480 B-6 3 1507 251 502 3 95 285 7,971 feet: C-8 3 1508 251 503 3 95 285 7,971 16,815 R1-5.9 3 1510 252 503 4 95 380 10,629 K-7 3 1529 255 510 4 95 380 10,629 C-4 3 1874 312 625 4 95 380 10,629 251-ton max. F-6 3 1879 313 626 4 95 380 10,629 allow. load: J-6 3 1942 324 647 4 95 380 10,629 125 J-4 3 1995 333 665 4 95 380 10,629 13-3/8" 0.480 Q-9 3 2003 334 668 4 95 380 10,629 feet: R-9 3 2003 334 668 4 95 380 10,629 11,875 448 481 42,380 $1,157,416 28

Load-Matching Design Approach (continued) Select viable pile type(s) and section(s) for selected allowable pile loads (91 T, 180 T, 251 T ). Estimate individual pile lengths required for selected pile capacities. Calculate total pile lengths required for project. Calculate total pile cost for project. Perform additional iterations as desired. 29

$19.16 / ft F.S. = 2.00 Maximum Optimum Required Allowable "Ultimate" 3 Capacities (91, 180, and 251 tons) 1 Capacity (10.75 x 0.188, 63 tons) Column Min. Column Pile Pile Est. Pile Est. Pile(s) Est. Pile(s) Est. Pile Est. Pile(s) Est. Pile(s) Line No. Load, Load, Capacity, No. Length, Footage, Cost, Number Length, Footage, Cost, Designation of Piles kips tons tons of Piles feet feet dollars of Piles feet feet dollars 0.A-8.5 1 158 79 158 1 62 62 1,340 2 58 116 2,223 0.A-0.5 1 180 90 180 1 62 62 1,340 $21.61 / ft 2 58 116 2,223 P-3.3 1 181 91 181 1 62 62 1,340 91-ton max. 2 58 116 2,223 P-3.7 1 181 91 181 1 62 62 1,340 allow. load: 2 58 116 2,223 P-4.5 1 181 91 181 1 62 62 1,340 71 2 58 116 2,223 P-5 1 181 91 181 1 62 62 1,340 10.75x0.365 2 58 116 2,223 P-5.5 1 181 91 181 1 62 62 1,340 feet: 2 58 116 2,223 P-6 1 181 91 181 1 62 62 1,340 4,402 2 58 116 2,223 0.A-8 1 203 102 203 1 86 86 2,405 2 58 116 2,223 M.5-8 1 228 114 228 1 86 86 2,405 $27.97 / ft 2 58 116 2,223 N-8.5 1 360 180 360 1 86 86 2,405 180-ton max. 3 58 174 3,334 P.7-8.5 1 360 180 360 1 86 86 2,405 allow. load: 3 58 174 3,334 P-0.5 1 360 180 360 1 86 86 2,405 108 3 58 174 3,334 P-8.5 1 360 180 360 1 86 86 2,405 13-3/8" 0.480 3 58 174 3,334 Q.8-3 1 360 180 360 1 86 86 2,405 feet: 3 58 174 3,334 Q-0.5 1 360 180 360 1 86 86 2,405 9,288 3 58 174 3,334 M.5-4 1 368 184 368 1 95 95 2,657 3 58 174 3,334 J-5 2 748 187 374 2 95 190 5,314 6 58 348 6,668 G-7 3 1479 247 493 3 95 285 7,971 251-ton max. 12 58 696 13,335 H-7 3 1479 247 493 3 95 285 7,971 allow. load: 12 58 696 13,335 K-6 3 1484 247 495 3 95 285 7,971 177 12 58 696 13,335 B-7 3 1487 248 496 3 95 285 7,971 13-3/8" 0.480 12 58 696 13,335 B-6 3 1507 251 502 3 95 285 7,971 feet: 12 58 696 13,335 C-8 3 1508 251 503 3 95 285 7,971 16,815 12 58 696 13,335 R1-5.9 3 1510 252 503 4 95 380 10,629 12 58 696 13,335 K-7 3 1529 255 510 4 95 380 10,629 13 58 754 14,447 C-4 3 1874 312 625 4 95 380 10,629 251-ton max. 15 58 870 16,669 F-6 3 1879 313 626 4 95 380 10,629 allow. load: 15 58 870 16,669 J-6 3 1942 324 647 4 95 380 10,629 125 16 58 928 17,780 J-4 3 1995 333 665 4 95 380 10,629 13-3/8" 0.480 16 58 928 17,780 Q-9 3 2003 334 668 4 95 380 10,629 feet: 16 58 928 17,780 R-9 3 2003 334 668 4 95 380 10,629 11,875 16 58 928 17,780 448 481 42,380 $1,157,416 1,560 90,480 $1,733,597 $576,181 30

$19.16 / ft F.S. = 2.00 Maximum Optimum Required Allowable "Ultimate" 3 Capacities (91, 180, and 251 tons) 1 Capacity (10.75 x 0.188, 63 tons) Column Min. Column Pile Pile Est. Pile Est. Pile(s) Est. Pile(s) Est. Pile Est. Pile(s) Est. Pile(s) Line No. Load, Load, Capacity, No. Length, Footage, Cost, Number Length, Footage, Cost, Designation of Piles kips tons tons of Piles feet feet dollars of Piles feet feet dollars 0.A-8.5 1 158 79 158 1 62 62 1,340 2 58 116 2,223 0.A-0.5 1 180 90 180 1 62 62 1,340 $21.61 / ft 2 58 116 2,223 P-3.3 1 181 91 181 1 62 62 1,340 91-ton max. 2 58 116 2,223 P-3.7 1 181 91 181 1 62 62 1,340 allow. load: 2 58 116 2,223 P-4.5 1 181 91 181 1 62 62 1,340 71 2 58 116 2,223 P-5 1 181 91 181 1 62 62 1,340 10.75x0.365 2 58 116 2,223 P-5.5 1 181 91 181 1 62 62 1,340 feet: 2 58 116 2,223 P-6 1 181 91 181 1 62 62 1,340 4,402 2 58 116 2,223 0.A-8 1 203 102 203 1 86 86 2,405 2 58 116 2,223 M.5-8 1 228 114 228 1 86 86 2,405 $27.97 / ft 2 58 116 2,223 N-8.5 1 360 180 360 1 86 86 2,405 180-ton max. 3 58 174 3,334 P.7-8.5 1 360 180 360 1 86 86 2,405 allow. load: 3 58 174 3,334 P-0.5 1 360 180 360 1 86 86 2,405 108 3 58 174 3,334 P-8.5 1 360 180 360 1 86 86 2,405 13-3/8" 0.480 3 58 174 3,334 Q.8-3 1 360 180 360 1 86 86 2,405 feet: 3 58 174 3,334 Q-0.5 1 360 180 360 1 86 86 2,405 9,288 3 58 174 3,334 M.5-4 1 368 184 368 1 95 95 2,657 3 58 174 3,334 J-5 2 748 187 374 2 95 190 5,314 6 58 348 6,668 G-7 3 1479 247 493 3 95 285 7,971 251-ton max. 12 58 696 13,335 H-7 3 1479 247 493 3 95 285 7,971 allow. load: 12 58 696 13,335 K-6 3 1484 247 495 3 95 285 7,971 177 12 58 696 13,335 B-7 3 1487 248 496 3 95 285 7,971 13-3/8" 0.480 12 58 696 13,335 B-6 3 1507 251 502 3 95 285 7,971 feet: 12 58 696 13,335 C-8 3 1508 251 503 3 95 285 7,971 16,815 12 58 696 13,335 R1-5.9 3 1510 252 503 4 95 380 10,629 12 58 696 13,335 K-7 3 1529 255 510 4 95 380 10,629 13 58 754 14,447 C-4 3 1874 312 625 4 95 380 10,629 251-ton max. 15 58 870 16,669 F-6 3 1879 313 626 4 95 380 10,629 allow. load: 15 58 870 16,669 J-6 3 1942 324 647 4 95 380 10,629 125 16 58 928 17,780 J-4 3 1995 333 665 4 95 380 10,629 13-3/8" 0.480 16 58 928 17,780 Q-9 3 2003 334 668 4 95 380 10,629 feet: 16 58 928 17,780 R-9 3 2003 334 668 4 95 380 10,629 11,875 16 58 928 17,780 448 481 42,380 $1,157,416 1,560 90,480 $1,733,597 $576,181 31

Talk Outline Support Cost Define Pile Support Cost Based on Available Support Based on Utilized Support Load-Matching Evaluations Philosophy Define Optimum Allowable Pile Load Case Histories Medium/Large Small 32

Condominiums Relatively small project, approximately 200 piles required. Renovation of a former storage warehouse into condominiums. Piles required only beneath small building addition. Existing geotechnical engineering report prepared for different site development plans. A review of existing recommendations relative to currently proposed development was desired. 33

Number of Piles Optimum Allowable Pile Load Histogram Condominiums 36 42 50 54 72 108 125 129 215 30 25 20 15 10 5 0 30 50 70 90 110 130 150 170 190 210 Optimum Allowable Pile Load, tons 34

Condominiums - Proposed Designs Allowable Number Estimated Design Load, tons of Piles Footage Original 70 205 15,580 35

Number of Piles Optimum Allowable Pile Load Histogram Condominiums 36 42 50 54 72 108 125 129 215 30 25 20 15 10 5 0 30 50 70 90 110 130 150 170 190 210 Optimum Allowable Pile Load, tons 36

Condominiums - Proposed Designs Allowable Number Estimated Design Load, tons of Piles Footage Original 70 205 15,580 Revised 72 180 14,040 SAVE: 25 1,540 $34,250 + cap costs on $346,500 worth of piles 37

Condominiums - Proposed Designs Allowable Number Estimated Design Load, tons of Piles Footage Original 70 205 15,580 Revised 72 180 14,040 Alternate 100 130 $60,000 savings 72 tons per pile x 180 piles = 12,960 tons to support 12,960 tons / 100 tons per pile = 130 piles Save 50 piles & $60,000? 38

Number of Piles Optimum Allowable Pile Load Histogram Condominiums 36 42 50 54 72 108 125 129 215 30 25 20 15 10 5 0 30 50 70 90 110 130 150 170 190 210 Optimum Allowable Pile Load, tons 39

216-ton column load 216-ton column load 72 tons 72 tons 72 tons 100 tons 100 tons 100 tons 40

Condominiums - Proposed Designs Allowable Number Estimated Design Load, tons of Piles Footage Original 70 205 15,580 Revised 72 180 14,040 Alternate 100 164 15,744 SAVE: 16 (not 50) -1,704 ($37,897) (if same pile section is used) 41

Conclusions Consider using higher-capacity piles (when building loads warrant) Consider matching (optimizing) allowable pile loads to column loads Evaluate design options/alternatives using actual column loads and allowable pile load histogram All should result in more-cost-effective driven-pile foundations 42

Questions / Comments? 43