1. Jennifer Soderstrom University of Washington
Seismic Evaluation of Prestressed and Reinforced Concrete Pile-Wharf Deck Connections
Jennifer Soderstrom
University of Washington

2. Introduction Ports represent a large economic investment for a region
Direct damage to the port of Kobe, Japan estimated to exceed U.S.$11 billion
It is worthwhile to evaluate the seismic performance of port facilities

3. Typical Wharf Section

4. Pile-Deck Connections
Piles are the sole supports for large gravity loads
Detailing must be sufficient to allow pile forces to develop and hinges to form
Repair and inspection can be difficult, so a connection should remain undamaged in a large seismic event

5. Prototype Connections
Survey of Wharves in Los Angeles, Oakland and Seattle
Connection types used included:
Precast Pile Connection
Pile Extension Connection
Batter Pile Connection

6. Precast Pile Connection
Most common connection was a 24 in octagonal prestressed pile
Pile set 2 in into deck
Hooked dowels grouted in pile ducts
Varying development lengths

7. Pile Extension Connection
Cast prior to deck if length > 6 in
Hooked dowels grouted in pile ducts and passing through extension
Varying development lengths
Extended spiral in some connections

8. Pile Section 24 in octagonal prestressed pile most common
Details varied

9. Test Methodology Connection types investigated in this study:
Pile Extension Connections
No spiral reinforcement in joint region
Moderate spiral reinforcement in joint region
Precast pile connections
No axial load
222 kip axial load

10. Specimen 1: Pile Extension

11. Specimen 2: Pile Extension w/Spiral

12. Specimens 3&4: Precast Pile

13. Test Setup

14. Axial Load System

15. Testing Procedure Modified ATC-24 loading sequence
Lateral displacement from 0.05% to 10.6% drift
% drift = lateral deflection / pile length

16. Experimental Results Test observations Force-deflection history
Moment-curvature history
Average curvature
Strain curvature
Strain distribution
Incremental strain distribution

17. Test Observations – pile cracking1 2 3 4
Cracking at 1.0% drift

18. Test Observations – deck cracking
Specimen 1
Specimen 3
Specimen 2

19. Test Observations – end of tests 1, 2
Specimen 2
Specimen 1

20. Test Observations – end of tests 3, 4
Specimen 3
Specimen 4

21. Force-Deflection History – specimen 1
Peak load = 26.5 kips at 4.5% drift

22. Force-Deflection History – specimen 3
Peak load = 30.7 kips at 3.0% drift

23. Force-Deflection History – specimen 4
Peak load = 38.1 kips at 1.5% drift

24. Moment-Curvature History
Average curvatures
Calculated over intervals 0 to ½ diam. and ½ to 1 diam.

25. Moment-Average Curvature
½ to 1 diam. (upper)
0 to ½ diam. (lower)
Specimen 1
Lower curvature 2-3 times greater than upper curvature

26. Moment-Average Curvature
½ to 1 diam. (upper)
0 to ½ diam. (lower)
Specimen 4
Lower curvature 8-10 times greater than upper curvature

27. Moment-Curvature History
Strain curvatures
Calculated at distances of 8.25, 0 and –5 in from interface

28. Moment-Strain Curvature
interface
-5 in
Specimen 2
Strain curvatures highest in pile section

29. Moment-Strain Curvature
interface
-5 in
Specimen 4
Strain curvatures highest in deck

30. Strain Distribution Specimens 1, 2
Peak strains between interface and ½ diameter
Yield at 1.0% drift

31. Strain Distribution Specimen 3
Peak strains in deck, 5 in below interface
Yield at 0.75% drift
High strains in lower bar

32. Strain Distribution Specimen 4
Peak strains in deck, 5 in below interface
Yield at 1.0% drift

33. Incremental Strain Distribution
D Strains at 1000 kip-in moment, first cycles
Exponential distribution indicates good bond
Specimen 2
Good bond within deck

34. Incremental Strain Distribution
D Strains at 1000 kip-in moment, specimen 3
D Strains at 1500 kip-in moment, specimen 4
Specimen 3
Slip in top 5 in of deck
Good bond in pile section

35. Conclusions All connections had large rotational capacities
Precast pile connections were initially stiffer
and stronger, but experienced greater
deterioration than pile extensions
A moderate axial load increased strength by
25%, but caused greater deterioration at drift
levels above 2.0%

36. Conclusions
Pile extensions dissipated more energy at high drift levels through continued flexural cracking, while damage in the precast connection was concentrated in large cracks near the interface
Precast pile connections experienced bond
slip and rocking in early load cycles

37. Conclusions The addition of spiral reinforcement in the
joint region did not appear to have a
significant effect on pile extension
performance

38. Jennifer Soderstrom University of Washington
Seismic Evaluation of Prestressed and Reinforced Concrete Pile-Wharf Deck Connections
Jennifer Soderstrom
University of Washington