PILE LOAD TEST AND IMPLEMENTATION OF LRFD SPECIFICATIONS: A CASE STUDY OF CAMINADA BAY BRIDGE PROJECT IN LOUISIANA

摘要

An instrumented pile load test was performed as part of the foundation design for the CaminadaBay Bridge project in south Louisiana. As part of the load test program, both static and dynamicload tests were performed. The load-transfer curve of test pile was obtained from the strainmeasurements using the sister-bar strain gages at six locations along the pile shaft. The test pileresistance was determined using the Tomlinson method for cohesive soils and the Nordlundmethod for cohesionless soils. The dynamic and static load testing results indicated that the testpile did not achieve the desired design resistance. The static analysis model was calibrated basedon the observations of pile load testing program. The design pile length was revised to gainbenefit from the shallower scour depths for the revised pile design. Due to the low resistance ofthe test pile, the engineer determined to use dynamic testing on the production piles to ensureadequate resistances. Taking advantage of the static load test of the instrumented test pile,instead of simply using the smaller resistance factor from dynamic tests, the engineer combinedthe results of the two test methods and used a combination of resistance factors from both thestatic and dynamic load tests. This paper presents the evaluation of load test results and therationale used for the resistance factor selection.