Load–Displacement Relations of a Driven Steel Pipe Piles from Static and Rapid Load Tests, and Empirical Formulas Based on SPT and CPT: A Case Study at Sashima Test Yard

Empirical formulas for estimating the shaft resistance τf and the tip resistance qb of a vertically loaded pile are widely used all over the world. Standard penetration test (SPT) N-value or cone penetration test (CPT) tip resistance qt is used in the empirical formulas. Coefficients used in the empirical formulas have been determined through the comparison with static load test (SLT) results. In this study, SLTs and rapid load tests (RLTs) were carried out on driven steel pipe piles (SPPs) at the test site of Jibanshikenjo Co., where SPT and CPTs were densely conducted. The shaft resistance and the tip resistance measured in SLTs are compared with those from RLTs as well as various pile design formulas. Furthermore, load–displacement relations from SLTs are compared with those τf, qb, and shear moduli of surrounding soils estimated using empirical formulas.