Nonlinear Bending of Deep Foundation Piles

Abstract

Freeport McMoRan Resource Partners are planning to construct a number of offshore platforms for the purpose of extracting sulphur from a large deposit discovered in Block 299 of the Main Pass Area of the Gulf of Mexico.Subsidence and lateral spreading of the nearsurface sediments are expected to accompany the removal of the sulphur. As the soil moves laterally, the foundation piles will generally conform closely with the displaced shape of the soil, particularly in deep layers of sand. At some locations, the differential movement of sand layers separated by weaker clay layers produces very severe bending deformations in the piles.The unique design problem for the Main Pass 299 platform foundations was not related to satis@ing conventional safety factors, but rather, was concerned with selecting cross-sections which, although strained lastically, will remain in [ equilibrium with t e imposed soil motions while retaining structural integrity.

Reliability-Based Design Criteria for Freeport McMoRan Main Pass Block 299 Sulphur Mine Platforms

“…analyses have been substantiated by the detailed analyses of the nonlinear soil -pile interactions [21]. The foregoing simplified pile-soil interaction accomplished without significant problems.…”