Finite element analysis of bridge approach slabs considering soil

Finite element analysis of bridge approach slabs considering soil – structure interaction

The objective of this paper is to present results of a study employed to identify the probable causes and location of cracking in bridge approach and transition slabs and the factors influencing the crack development. A finite element (FE) model has been developed to study the cracking phenomenon in bridge approach and transition slabs under vehicular live load and soil settlement. A field survey was conducted to determine the extent and probable causes of crack development in these slabs at various bridge sites in the State of New Jersey, USA. The data collected from field observations were compared with those predicted by the FE model to determine its reliability and consistency. The FE model was employed in conducting a parametric study to evaluate the effect of various designs as well as soil parameters on the cracking behavior of the slabs. The results from the parametric study showed that increasing the slab thickness would significantly increase the cracking load carrying capacity of the approach slab. However, an increase in soil settlement has an adverse effect on its cracking load carrying capacity. Based on the results from this study, two design alternatives, which exhibited better cracking resistance than the existing design detail, are also presented.