Reliability Analysis of Differential Settlement of Strip Footings by Stochastic Response Surface Method

The differential settlement of structures which are founded on soil is occurred due to heterogeneity of the soil, and it would not be beneficial to the serviceability of the structures. The heterogeneity of the soil can be implemented by qualified probabilistic analysis. This paper studies the reliability of differential settlement between two strip footings by stochastic finite element method (SFEM). For this purpose, stochastic response surface method (SRSM) as a non-intrusive formulation of SFEM is used. The linear-elastic model is used to represent the soil behavior. The Young's modulus (E) is considered as spatially random variable and modeled as lognormal random field. The well-known Karhunen-Loeve expansion is used for discretization of the random field. The results of proposed SRSM are compared with those of the Monte Carlo simulation. The results show that the horizontal and vertical autocorrelation lengths are important parameters in reliability analysis of differential settlement. Furthermore, the probability of failure increases with increasing the coefficient of variation of Young's modulus.