Uncertainty Analysis in Predicting Differential Settlement at the Interface between Bridge Deck and Subgrade

Abstract

This work involved an uncertainty analysis of a case study of a bridge in the Wenzhou area of China. A pile–slab composite foundation was used to mitigate the bump at the end of the bridge. The uncertainty analysis was performed using Monte Carlo (MC) simulations and the response surface method (RSM) combined with the first-order second-moment method (FOSM) and the finite element software Plaxis 2D. In addition, the soft soil creep (SSC) model was used to simulate long-term settlement of soft soil. The results obtained using the MC and RSM methods were consistent and effectively completed the uncertainty analysis to correct the parameters, but the RSM method was more efficient and accurate. In addition, three parameters that are most sensitive to long-term settlement in the soft soil creep model were identified: modified secondary compression index μ*, preoverburden stress POP, and modified compression index λ*. After parameter correction, the finite element calculation results show that this new type of pile–slab composite foundation can still effectively mitigate the problem of the bump at the end of the bridge 10 years after opening to traffic; the maximum settlement was 36.36 mm and the rate of longitudinal slope change of the surface settlement curve was 0.31.