Proceedings - Fifth International Conference & Exhibition on Piling and Deep Foundations, 1994, Bruges, Belgium, (DFI)
Dynamic testing of large capacity precast concrete piles in the Port of Long Beach
Dr. A.E. Holeyman & K. Bhushan
The paper presents and discusses results of dynamic pile tests performed as part of the indicator program for the Berths 245-247 widening at Pier J of the Port of Long Beach, California. 120-ft (36.6 m) long, 24-in (0.61 m) octagonal prestressed precast concrete piles were driven using a 14.6 kips (65 kN) diesel hammer through variable alluvium and into a dense sand layer characterized by a cone resistance of approximately 300 tsf (30 Pa). One objective of the program was to establish penetrability of intermediate dense sand layers and evaluate the need for jetting. Several dynamic matching procedures were used to evaluate the load bearing behavior of the piles. In spite of the high energy delivered, the maximum transient displacement during the test was of the order of 0.4 to 0.8 inches (10 to 20 mm), which resulted in only a partial mobilization of the soil resistance at the pile tip (880 kips or 4 MN). It is believed that in that case a hyperbolic stress-strain relationship is better able than an elasto-plastic relationship (I.e. Smith model) to evaluate the bearing capacity in higher ranges. Time dependent resistance gain is highlighted by comparing the resistance mobilized at the end of driving, 24 hours after driving, and 5 days after driving.
|article #803; publication #36 (IC-1994)|