LIMIT STATE ANALYSIS OF FIXED-HEAD CONCRETE PILES UNDERLATERAL LOADS

摘要

Under seismic loads, deep foundations with fixed pile/pile-cap connection may be subjected to a largecurvature demand at the pile head. Damage induced by local inelastic deformation depends on themagnitude of the lateral displacement imposed on the pile. In this paper, an analytical model relating thedisplacement ductility factor to the local curvature ductility demand is proposed for fixed-head pilesembedded in cohesive and cohesionless soils. The model indicates that the curvature ductility demanddepends on the strength and stiffness of the soil-pile system, as well as the location and length of theplastic hinges. The model is useful for design of fixed-head piles since it is capable of estimating theseverity of the local damage in the pile for a wide range of pile and soil properties. The versatility of themodel is illustrated using an example of a fixed-head concrete pile constructed in soil types currentlyclassified in the US building codes. Seismic performance of the pile subjected to displacement ductilityfactor commensurate with the current design is assessed for different soil conditions.