Probabilistic settlement analysis of rafts using first order reliability method

Settlement of foundations is of crucial concern as it affects the strength and durability of the superstructure as well as the foundation itself. Traditional settlement analysis methodologies cease to incorporate uncertainties associated with design parameters of the foundation. Probability-based settlement analysis of raft foundations accounting for the uncertainties in design variables is presented in this paper. Probabilistic soil-structure interaction model of the raft is developed duly considering the variability involved in various design parameters. The first order reliability method (FORM) is used to evaluate the probability of failure and reliability index associated with the settlement of the raft foundations. Parametric sensitivity analysis is also carried out to identify the important design variables that affect the performance of the raft foundation in connection with the settlement limit state. The reliability analysis of the raft employing the finite element method is also presented.