A CPT-based dynamic p-y curve method for seismic analysis and design of pile in sand

Abstract

This paper presents a dynamic p-y analysis method based on the cone penetration test (CPT) for piles embedded in sand. Focus was given on the full utilization of the cone resistance (q_c) for the dynamic p-y analysis. A pseudo-static approach was adopted to establish the dynamic p-y curve function. Static and dynamic stiffness and damping in the dynamic p-y function were all formulated as a function of the cone resistance, which enabled the direction application of CPT results into the seismic pile design. The continuous depth profile of the cone resistance was utilized in the CPT-based dynamic p-y analysis, which was programmed with an algorithm that involved steps for calculating the equivalent static load and solving the dynamic stiffness matrix. The advantageous aspect of fully utilizing in-situ test results for the seismic pile design was emphasized, which was effective to reduce uncertainties involved in soil characterization process based on sampling and lab testing of conventional approach. A case example of centrifuge load test was selected from the literature and adopted to compare measured and estimated pile displacements using the CPT-based dynamic p-y analysis method. From the comparison, it was shown that the calculated depth profile of lateral pile displacement was in reasonably close agreement with the measured displacement profile.