Use of interaction domains for a displacement-based design of caisson foundations

Abstract Caisson foundations, typically adopted for both onshore and offshore structures, are usually subject to combined loading acting during working conditions exceptional events such as earthquakes. Assessment of their performance under general loadings is therefore fundamental, serviceability ultimate limit states. In this study, a simplified displacement-based approach, aimed at preliminary designing caisson foundations subjected loading, presented. Such an approach requires the definition interaction domains (IDs) generalised pushover curves, together with assumption associative flow rule. The IDs curves obtained by interpreting results set 3D finite element nonlinear static analyses, where response massive cylindrical embedded in layered soil profile centred vertical ( N ) loads – Q M ), investigated. Following previous works, influence initial factor embedment ratio on shape size Additionally, effect drainage discussed. Role load reference point (LRP) also assessed, since suitable choice LRP may strongly simplify geometrical representation ID. Analytical expressions dimensionless presented used design stage evaluate maximum given threshold displacement, so not exceed either or