1. DRIVEN PILE SPECIFICATIONS
Chapter 11

2. Project Plans should include: (11-1, see list)
Ultimate Capacity NOT “Safe Bearing” etc. (11-1)
Good Spec should include basic components (11-2)

3. Back Ground (11-4 thru 11-5)
Ultimate Capacity replaces Design Load
Approval of Driving Equipment
Replace Dynamic Formulas

4. Generic Specification (11-6)
Owner responsible to “estimate” pile lengths
Contractor responsible to provide and install undamaged piles.
Must satisfy minimum required depth
of embedment
Must drive to required ultimate capacity, w/ reasonable BC

5. Approved Hammers (11-9)
OED Measure Stroke (11-10)
CED Bounce Chamber Pressure (11-10)

6. Proximity Switches
Transmitter
Battery

7. Approval of Pile Driving Equipment (11-11)
Wave Equation Equipment Form (11-14)
Reasonable Blow Count bpf (11-15)
Driving Stresses (11-15, chap 10)
Concrete (f’c, fpe)
Steel (fy)

8. Grade 50 ksi

9. ASD Factors of Safety (11-16)
Ultimate Pile Capacity (11-17)
Must be shown on Plans: ASD
Or LRFD
Optimum Pile Installation –
Maximum Curvature (11–17)

10. Drive System Components (11-19)
Hammer Cushion (11-19)
Pile Cushion w/ concrete piles (11-20)
New Pile Cushion for each Pile
Used Pile Cushion for Re-Strikes
Leads (11-21)

11. Hammer Cushions
Are materials placed between the pile hammer ram and the helmet
It’s function ?
To relieve impact shock and thereby protect the hammer while at the same time transmit consistent energy to the pile

12. Hammer Cushions Recommended:
Not Recommended:
Man-made cushion materials made of micarta, nylon, urethane, or other polymers
Hardwood
Plywood
Wire rope
Asbestos

13. Aluminum - micarta
NIM

15. hammer-tex
NIM

16. NIM

17. NIM

18. NIM

19. Pile Cushion
Concrete piles require a pile cushion between the helmet and the pile lead
Typically made of plywood, hardwood, plywood & hardwood composites, or other man-made materials

21. NIM

22. NIM

23. Followers(11-21) Only with Engineer’s Approval
Jets (11-22) Only with Engineers Approval
Pre-Boring (11-22) Only with Engineers Approval

24. Follower
Is a member interposed between a pile hammer and a pile to transmit blows when the pile head is below the reach of the hammer
Use of a follower is accompanied by a loss of energy delivered to the pile due to compression of the follower & losses in connection

25. NIM

27. Jetting
The use of a water or air jet to facilitate pile driving by displacing parts of the soil
Jetting is useful in driving piles through very dense material

29. NIM

30. Predrilling
Soil augers or drills used where jetting is inappropriate / ineffective to
- Penetrate obstructions, boulders, debris fills
- Facilitate pile placement through embankments
- Reduce ground movements
Predrilled hole diameter 100 mm less than diagonal of square pile, or 25 mm less than diameter of round pile

31. NIM

32. Spudding
The act of opening a hole through dense material by driving or dropping a short & strong member & then removing it
Used as an alternate to jetting or predrilling in upper soil consisting of miscellaneous fill

33. NIM

34. Gates Formula – limited (11-23)
Phase in WEAP (11-25)
Static Load Tests (11-26 & 27)
Include Dynamic Testing (11-28)
Contractor Responsibilities (11-29)
Restrike (11-30)
Duration
Cold Hammer

35. Tolerances (11-35)
Pile Heave (11-35)
Installation Sequence (11-36)
Unsatisfactory Piles (11-36)
Pay Items (11-40)

36. ANY QUESTIONS ?