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by

C. Vipulanandan (Vipu) Ph.D., P.E.Professor of Civil Engineering

Director of CIGMAT & THC-IT

DFI 2012 ConferenceHouston, Texas

October 16, 2012

Part 8: Specifications & Experience

I G M A TC

1994

(a) Specifications (GEC, DFI)

(b) CIGMAT/UH Project

Part 8. Specifications and Experience

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3

• Kreneck Road Bridge Project

Load Tests

Battered ACIP Piles

Load Tests and the Lessons Learned

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Project Location

Site Information and Conditions (cont’d)

Soil Profile at Krenek Road

(ACIP Pile)

Soil Profile at Runneburg Road (Driven Pile)

Sand

Clay

Clay

Sand

Clay

Clay

Clay

42 ft47 ft52 ft

39 ft40 ft

49 ft50 ft

Sand

Sand

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280-ft long bridge at US 90/Krenek Road

90 ft 100 ft 90 ft

16 vertical central bent piles under 4 columns,

4-pile groups57-ft long, 18 in piles

8 in-battered piles,8 out-battered piles,

4:1 batter 62-ft long, 18 in piles

5 ft

7 ft

8.5 ft

43 ft42 ft

52 ft

8 in-battered piles, 8 out-battered piles,

4:1 batter

62-foot long, 18-in piles w/ full-length cages

16 vertical piles in 4, 4-pile groups

57-foot long, 18-in piles w/ full-length cages

Grade Crossing: 280-foot-long Bridge at US 90 / Krenek Road, in

Crosby, Texas

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Basis of Design…..

Simple Design Methods for Ultimate Compressive Resistance

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Load Testing: Both ACIP and Driven Piles….

(for verification of capacity estimation method)

Load-Settlement Curves for ACIP and PC Driven Test Piles

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

1.3

1.4

1.5

1.6

0 50 100 150 200 250 300

Load ︵ton ︶

Set

tlem

ent

︵in

︶

ACIP Pile ︵215 tons ︶

Dr iv en Pile ︵165 tons ︶

Dav is s on's Cr iter ia ︵ACIP ︶

Dav is s on's Cr iter ia ︵Dr iv en Pile ︶

18-in. by 57 feet long16-in by 46

feet long

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Full-Scale Load Tests (cont’d)

• Load transfer behavior of ACIP pile– ACIP Pile supported by

side resistance

– Almost zero end bearing due to soil mining(depressuring of the sand during drilling into waterbearing sand)

0

5

10

15

20

25

30

35

40

45

50

55

60

65

-50 0 50 100 150 200 250

Load (tons)

Dep

th (

ft)

Sand

SandClay

Clay

Unit side shear resistance in clay: driven and ACIP piles at US 90 and

Krenek/Runneberg Roads

• Driven test pile: 16-in. sq. PC by 46 feet long:

Developed shearAvailable shear

() = 0.53

• ACIP test pile: 18-in. by 57 feet long:

Developed shear

Available shear

() = 0.83

“Design Loads” are 90 Tons w/ FS = 2

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280-ft long bridge at US 90/Krenek Road

90 ft 100 ft 90 ft

16 vertical central bent piles under 4 columns,

4-pile groups57-ft long, 18 in piles

8 in-battered piles,8 out-battered piles,

4:1 batter 62-ft long, 18 in piles

5 ft

7 ft

8.5 ft

43 ft42 ft

52 ft

Site Information and Conditions (cont’d)

ACIP Pile Design Facts– TxDOT design method for drilled shafts (1972)

– No. of ACIP piles = 64• Abutment piles = 32 (2 abutments)

• Central bent piles = 32 (8 columns)

– Diameter of ACIP pile = 18 in (0.46 m)

– Length of ACIP pile Test pile = 62 ft (18.9 m)

Abutment pile = 62 ft (18.9 m)

Central bent pile = 57 ft (17.4 m)

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Bridge foundation construction experiences

1. Drilling ACIP piles are formed by

rotating a continuous-flight auger (CFA) into the ground

to a predetermined tip depth.

downward

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2. GroutingAs the auger is being

withdrawn, sand-cement grout is injected

continuously through the hollow stem of the auger.

Grout Mix Truck for Pumping

upward

Grout line

Flow Meter Pressure Transducer

QQula

Quality Controls

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Bullet-nosed cages

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3. Inserting Steel CageReinforcing steel cage

is inserted into the grout after it is fully

withdrawn.

Full-lengthsteel cage

roller

Drilling an ACIP pile with out-batter for an abutment

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PVC pipe skids for batter pile cages

Inserting a 62-foot rebar cage on a

4:1 batter

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(1) Specifications and Guidelines are available for ACIP Piles.

(2) Real-time Monitoring of Grout Volume and Pumping Pressure are Important.

(3) Load Tests on Site are Encouraged.

CONCLUSIONS

I G M A TC

1994