Critical Appraisal of Codes for Foundation Design and Role of Reliability-Based Approach

Abstract

The variabilities or uncertainties of the design properties affect the design significantly, and a systematic approach to capture these variations is essential in the design of foundations. Reliability-based design (RBD) can consider the variations in the design properties in a systematic manner. First-order reliability method estimates reliability index at design points which can be used for correlated non-normal random variables. The influence of variability of design properties on foundation design is illustrated by comparing different design approaches such as IS code-based design, Eurocode 7-based design and RBD. Further, the significance of different failure modes and the influence of these on system reliability are also illustrated. Propagation of uncertainty is shown using probability distribution of the allowable load which is obtained using numerical simulations in conjunction with response surface method and Monte Carlo simulations.