Pile Driving IssuesPile Driving Issues

Mark McClelland, P.E.Mark McClelland, P.E.Geotechnical Branch ManagerGeotechnical Branch Manager

Texas DOTTexas DOT

Goldilocks??Goldilocks??

•• This soil it too hardThis soil it too hard……•• This soil is too softThis soil is too soft……•• This soil is just right!This soil is just right!

This soil is too hardThis soil is too hard……

•• PrestressedPrestressed concrete piling will refuse to concrete piling will refuse to advance into soils with Texas Cone advance into soils with Texas Cone PenetrometerPenetrometer (TCP) values harder than (TCP) values harder than 100 blows per foot (+/100 blows per foot (+/--).).

Texas Cone PenetrometerTexas Cone Penetrometer

•• Developed in 1949Developed in 1949•• 33”” Diameter hardened steel coneDiameter hardened steel cone•• 170 Pound hammer, 24170 Pound hammer, 24”” dropdrop•• 66”” Penetration or 50 blows, and repeatPenetration or 50 blows, and repeat

Texas Cone PenetrometerTexas Cone Penetrometer Typical ValuesTypical Values

•• 2(62(6””) ) -- 3(63(6””), Total 5 bpf (soft soil)), Total 5 bpf (soft soil)•• 18(618(6””) ) -- 22(622(6””), Total 40 bpf (stiff soil)), Total 40 bpf (stiff soil)•• 50(650(6””) ) -- 50(550(5””), Total 100 blows/11), Total 100 blows/11””

(Hard Soil, Soft Rock)(Hard Soil, Soft Rock)•• 50(150(1””) ) -- 50(.550(.5””), Total 100 blows/1.5), Total 100 blows/1.5””

(Hard Rock)(Hard Rock)

Why not just use a drilled shaft?Why not just use a drilled shaft?

•• Trestle pile interior bents are very cost Trestle pile interior bents are very cost effective.effective.

•• Some district like to offer both drilled shaft Some district like to offer both drilled shaft and pile alternates.and pile alternates.

•• But, it is generally better to use drilled But, it is generally better to use drilled shafts where significant amounts of 100+ shafts where significant amounts of 100+ bpfbpf material are present.material are present.

If you decide to go ahead with If you decide to go ahead with pilingpiling……

•• Minimize the amount of penetration into Minimize the amount of penetration into the 100 the 100 bpfbpf material.material.

•• Add note to plans directing the Add note to plans directing the contractorcontractor’’s attention to the hard material.s attention to the hard material.

•• Be aware of Item 404, Be aware of Item 404, ““Driving PilingDriving Piling”” penetration requirements.penetration requirements.

Item 404 Item 404 ““Driving PilingDriving Piling””

•• 404.3.B Penetration 404.3.B Penetration –– ““Drive piling to Drive piling to within 5 ft. of plan length within 5 ft. of plan length …… unless other unless other penetration requirements penetration requirements …… govern.govern.””

•• ““For unusually hard driving conditions For unusually hard driving conditions …… provide either pilot holes or jetting or a provide either pilot holes or jetting or a combination of both if plan penetration is combination of both if plan penetration is not obtained.not obtained.””

Item 404 Item 404 ““Driving PilingDriving Piling””

•• The contractor/inspector can cut off 5 feet The contractor/inspector can cut off 5 feet of pile if resistance, or more likely refusal, of pile if resistance, or more likely refusal, is met.is met.

•• If you need all of the length for stability or If you need all of the length for stability or scour, you must add a minimum scour, you must add a minimum penetration note!penetration note!

Minimum Penetration NotesMinimum Penetration Notes

•• Interior bent piling shall be driven to a Interior bent piling shall be driven to a minimum tip elevation of minimum tip elevation of xxx.xxxx.x..

oror

•• Interior bent piling shall be driven to the Interior bent piling shall be driven to the depth shown. No cutdepth shown. No cut--offs will be allowed.offs will be allowed.

Cutoffs vs. BuildupsCutoffs vs. Buildups

•• Cutting off a concrete pile is not a Cutting off a concrete pile is not a complicated task.complicated task.

•• Building up a concrete pile is difficult, time Building up a concrete pile is difficult, time consuming, expensive, and likely results in consuming, expensive, and likely results in a lower quality finished product.a lower quality finished product.

•• When in doubt, too long is (much) better When in doubt, too long is (much) better than too short!!than too short!!

This soil is too softThis soil is too soft……

•• PrestressedPrestressed concrete piling are the concrete piling are the foundation of choice in soft soils.foundation of choice in soft soils.

•• Some soils are sensitive to the disturbance Some soils are sensitive to the disturbance associated with pile driving.associated with pile driving.

•• These soils will lose strength during These soils will lose strength during driving, but will recover in a relatively driving, but will recover in a relatively short period of time.short period of time.

•• This will result in low apparent dynamic This will result in low apparent dynamic driving resistance.driving resistance.

What to do?What to do?

•• Be aware of the issue, particularly in Be aware of the issue, particularly in siltysilty materials, but also many clays.materials, but also many clays.

•• Some fine sands may show this as well.Some fine sands may show this as well.•• Consider test piling to establish Consider test piling to establish ““KK”” factor factor

with 7with 7--day day redriveredrive..•• Even 1 or 2Even 1 or 2--day day redrivesredrives will often recover will often recover

enough strength to accept the piling.enough strength to accept the piling.•• Load tests in extreme cases.Load tests in extreme cases.

KK--FactorFactor•• K Factor is a correction factor used to K Factor is a correction factor used to

correlate correlate ““ActualActual”” pile capacity to pile capacity to observed dynamic driving resistance.observed dynamic driving resistance.

•• ““ActualActual”” pile capacity can be determined pile capacity can be determined from static design method, pile from static design method, pile redriveredrive, , load test, or combination of above. load test, or combination of above.

•• Most often the Most often the ““KK”” factor is taken as the factor is taken as the ratio of the ratio of the redriveredrive resistance to the initial resistance to the initial driving resistance. driving resistance.

Recent Case HistoryRecent Case History Soft SoilsSoft Soils

IHIH--10 Bridge over Trinity River10 Bridge over Trinity River

Bridge Foundation FactsBridge Foundation Facts

•• 1818”” square square prestressedprestressed concrete pilingconcrete piling•• Loads (working) range from 75 tons/pile Loads (working) range from 75 tons/pile

to 175 tons/pileto 175 tons/pile•• Pile lengths range from 39Pile lengths range from 39’’ to 65to 65’’•• Main span piers on single, 88Main span piers on single, 88--pile footingspile footings•• Approach spans bents on two, 10Approach spans bents on two, 10--pile pile

footingsfootings

Soil ConditionsSoil Conditions

•• Alluvial depositsAlluvial deposits•• Highly variable soils across bridge siteHighly variable soils across bridge site•• Surface soils Surface soils –– soft clays and silts, loose soft clays and silts, loose

sand, mucksand, muck•• Deeper soils Deeper soils –– soft to medium clays and soft to medium clays and

siltysilty clays, medium sand, some clays, medium sand, some packsandpacksand

Bent 2 HistoryBent 2 History

•• Turned out to be typical of many of the Turned out to be typical of many of the piling on this side of the river.piling on this side of the river.

Pile Tip

Pile Driving commencesPile Driving commences……

•• Bent 2 Bent 2 –– Original stated design load was Original stated design load was 90 tons per pile90 tons per pile

•• Initial driving resistances (Engineering Initial driving resistances (Engineering News formula) range from 16 to 33 tons News formula) range from 16 to 33 tons per pileper pile

•• OneOne--day reday re--drives ranged from 55 to 100 drives ranged from 55 to 100 ton per pile. Most 60 ton per pile. Most 60 –– 65 tons65 tons

Date Hop Blows Distance in Bearing12/28/2006 5.5 4 12 18.0012/28/2006 5.5 4 12 18.0012/28/2006 5.5 4 12 18.0012/28/2006 5.5 4 12 18.0012/28/2006 5.5 5 12 22.3212/28/2006 5.5 5 12 22.3212/28/2006 5.5 4 12 18.0012/28/2006 5.5 4 12 18.0012/28/2006 5.5 5 12 22.3212/28/2006 5.5 4 12 18.0012/29/2006 6.5 13 12 64.4612/29/2006 6.5 11 12 55.37

Pile ADate Hop Blows Distance in Bearing

12/28/2006 5 3 12 12.3712/28/2006 5 3 12 12.3712/28/2006 5 4 12 16.3612/28/2006 5 4 12 16.3612/28/2006 5 5 12 20.2912/28/2006 5 5 12 20.2912/28/2006 5 5 12 20.2912/28/2006 5 4 12 16.3612/28/2006 5 5 12 20.2912/28/2006 5 4 12 16.3612/29/2006 7 14 12 74.1912/29/2006 6.5 13 12 64.46

Pile D

Date Hop Blows Distance in Bearing12/28/2006 6.5 7 12 36.3512/28/2006 6 6 12 28.9912/28/2006 6 6 12 28.9912/28/2006 6 7 12 33.5512/28/2006 6 6 12 28.9912/28/2006 6 5 12 24.3512/28/2006 6 6 12 28.9912/28/2006 6 5 12 24.3512/28/2006 6 6 12 28.9912/28/2006 6 7 12 33.5512/28/2006 6 6 12 28.9912/28/2006 6 6 12 28.9912/28/2006 6 6 12 28.9912/29/2006 7 16 12 83.5512/29/2006 7 13 12 69.41

Pile M

Date Hop Blows Distance in Bearing12/28/2006 6 6 12 28.9912/28/2006 6 6 12 28.9912/28/2006 6 6 12 28.9912/28/2006 5.5 5 12 22.3212/28/2006 5.5 5 12 22.3212/28/2006 5.5 5 12 22.3212/28/2006 5.5 5 12 22.3212/28/2006 5.5 6 12 26.5712/28/2006 5.5 5 12 22.3212/28/2006 5.5 6 12 26.5712/28/2006 5.5 5 12 22.3212/28/2006 5.5 5 12 22.3212/29/2006 7.5 14 12 79.4912/29/2006 7.5 13 12 74.37

Pile R

Bent 2 Bent 2 –– Now what?Now what?

•• Recheck original pile design calculations Recheck original pile design calculations –– Capacity should be 100 tons +/Capacity should be 100 tons +/--

•• Look at Gates formula Look at Gates formula –– Approximately Approximately the same resistance.the same resistance.

•• Look at Wave Equation analysis Look at Wave Equation analysis –– 10 10 –– 15% better resistance. Stroke is very 15% better resistance. Stroke is very close for a given set, so model seems close for a given set, so model seems reasonablereasonable

Bent 2 Bent 2 –– Now what? Now what?

•• 77--day reday re--drive on two pilingdrive on two piling•• Pile 1 Pile 1 –– 175 tons for first inch, dropping to 175 tons for first inch, dropping to

93 tons at 6 inches and stabilizing at 93 93 tons at 6 inches and stabilizing at 93 tons per piletons per pile

•• Pile 2 Pile 2 –– 175 tons for first inch, dropping to 175 tons for first inch, dropping to 65 tons at 6 inches and stabilizing at 60 65 tons at 6 inches and stabilizing at 60 tons per piletons per pile

Date Hop Blows Distance in Bearing12/28/2006 5 4 12 16.3612/28/2006 5 3 12 12.3712/28/2006 5.5 4 12 18.0012/28/2006 5.5 5 12 22.3212/28/2006 5.5 4 12 18.0012/28/2006 5.5 5 12 22.3212/28/2006 5.5 4 12 18.0012/28/2006 6 5 12 24.3512/28/2006 6 5 12 24.3512/28/2006 6 6 12 28.9912/28/2006 6 6 12 28.9912/28/2006 6 5 12 24.351/5/2007 7.5 3 1 175.591/5/2007 7.5 2 1 126.811/5/2007 7.5 2 1 126.811/5/2007 7 2 1 118.361/5/2007 7 3 2 92.631/5/2007 7 2 1 118.361/5/2007 7 3 2 92.631/5/2007 7 3 2 92.631/5/2007 7 3 2 92.631/5/2007 7 3 2 92.631/5/2007 7 3 2 92.631/5/2007 7.5 3 2 99.241/5/2007 7.5 3 2 99.241/5/2007 7 3 2 92.631/5/2007 7 3 2 92.63

K factor 1st-3" 5.88

Pile BDate Hop Blows Distance in Bearing

12/28/2006 6 7 12 33.5512/28/2006 6 6 12 28.9912/28/2006 6 6 12 28.9912/28/2006 6 6 12 28.9912/28/2006 6 6 12 28.9912/28/2006 6.5 7 12 36.3512/28/2006 6 8 12 38.0412/28/2006 6 7 12 33.5512/28/2006 6 5 12 24.3512/28/2006 6 6 12 28.9912/28/2006 6 7 12 33.551/5/2007 7.5 3 1 175.591/5/2007 7.5 2 1 126.811/5/2007 7 2 1 118.361/5/2007 7 2 1 118.361/5/2007 7 2 1 118.361/5/2007 7 2 1 118.361/5/2007 7 1 1 64.561/5/2007 7 1 1 64.561/5/2007 7 1 1 64.561/5/2007 7 1 1 64.561/5/2007 7 1 1 64.561/5/2007 7 1 1 64.561/5/2007 7 1 1 64.561/5/2007 6.5 1 1 59.951/5/2007 6.5 1 1 59.951/5/2007 6.5 1 1 59.951/5/2007 6.5 1 1 59.951/5/2007 6.5 1 1 59.95

K factor 1st-3" 4.18

Pile L

Bent 2Bent 2•• Initial driving gave poor results.Initial driving gave poor results.•• 11--day reday re--drives on 18 piling showed drives on 18 piling showed

significant increases in capacity, but significant increases in capacity, but nonenone of the piling attained design load. of the piling attained design load.

•• 11--day reday re--drives measure driving data for drives measure driving data for the entire first foot of driving, not the entire first foot of driving, not recording data for each inch. recording data for each inch.

•• 77--day reday re--drives both gave good capacity drives both gave good capacity initially, falling off dramatically as driving initially, falling off dramatically as driving progressed. Data captured inchprogressed. Data captured inch--byby--inch.inch.

Bent 2 ConclusionsBent 2 Conclusions

•• Initial pile driving data is worthless. Soil is Initial pile driving data is worthless. Soil is losing strength due to disturbance.losing strength due to disturbance.

•• 11--day reday re--drive is useful, but too soon to drive is useful, but too soon to show full strength recovery.show full strength recovery.

•• 77--day reday re--drive indicates pile capacities are drive indicates pile capacities are good.good.

The rest of the storyThe rest of the story……•• All footings on this side of bridge showed All footings on this side of bridge showed

the same tendencies.the same tendencies.•• All piling were left up for at least a 1All piling were left up for at least a 1--day day

rere--drive, with 2 per footing left for 7drive, with 2 per footing left for 7--day day rere--drive where necessary.drive where necessary.

•• Worst footings had two piling added, Worst footings had two piling added, turning 10turning 10--pile footings into 12pile footings into 12--pile pile footings, thereby reducing load per pile.footings, thereby reducing load per pile.

The rest of the rest of the storyThe rest of the rest of the story……

•• Decided to do some Decided to do some StatnamicStatnamic Load Load Testing on selected piling. Testing on selected piling.

•• BOOOM!!!!BOOOM!!!!

Why Why StatnamicStatnamic??

•• They were in Texas, having just They were in Texas, having just completed some drilled shaft testing in the completed some drilled shaft testing in the Corpus Christi area.Corpus Christi area.

•• Minimal setup. No reaction piling, beam, Minimal setup. No reaction piling, beam, jack, etc.jack, etc.

•• Minimal delay to contractor.Minimal delay to contractor.

377 kip ultimate = 94 ton allowable (FOS = 2)

Pile Driving IssuesPile Driving Issues

•• Hard Driving:Hard Driving:–– DonDon’’t plan to penetrate far into 100+ t plan to penetrate far into 100+ bpfbpf

material.material.–– Include plan notes when necessary.Include plan notes when necessary.–– Consider drilled shafts as option.Consider drilled shafts as option.

•• Soft DrivingSoft Driving–– Be aware of strength loss during driving.Be aware of strength loss during driving.–– Understand how to develop and apply KUnderstand how to develop and apply K--factor.factor.–– Consider test pile and load tests.Consider test pile and load tests.

Bridge DivisionBridge Division Geotechnical BranchGeotechnical Branch

•• Mark McClellandMark McClelland 512512--416416--22262226•• Marcus GalvanMarcus Galvan 512512--416416--22242224•• John DelphiaJohn Delphia 512512--416416--23592359•• Dina DewaneDina Dewane 512512--416416--25502550•• Scott WaltonScott Walton 512512--416416--25542554•• FidencioFidencio GonzalezGonzalez 512512--416416--25732573