Incorporating the effect of approach slab to the dynamic response of simply supported bridges under moving vehicle

Abstract

Reinforced concrete approach slabs serve as a transitional component between the roadway pavement and the bridge deck. Due to the settlement of the embankment soil, the slab is bent, and its slope grade will be suddenly changed resulting in bumps at both ends of the deck; this may increase the dynamic response of bridges induced by the interaction with moving vehicles. In addition, the presence of such bumps not only causes an uncomfortable ride but also exhibits a potentially hazardous condition to the traffic. Since most of the studies have considered either the interaction model between the slab and soil or between the bridge and moving load; in this study, a novel finite element model is established for the bridge under traffic loads, considering the presence of the approach slab that is simulated as a beam rested on a dynamic soil model. The separated models of the approach slab and bridge deck are validated by previous studies and demonstrate their accuracy in predicting the dynamic response of the bridge-vehicle system. A comprehensive parametric study is then performed considering the effect of the soil stiffness, the stiffness of the shear layer of the foundation, and the approach slab length. The results of the study are useful criteria for the practice design of the approach slab in different embankment conditions.