| A comprehensive two-dimensional nonlinear finite element parametric study is conducted to investigate the effects of a range of parameters of relevant soil-structure interaction systems (identified from the literature survey) as they relate to the behavior of bridge approaches. These parameters involve, approach slab dimensions, sleeper slab configurations, type of connections between approach slabs and abutments, embankment fill height, fill type densities, and abutment movement. The effects of the above parameters on approach slab length are investigated.; The Drucker-Prager constitutive laws with the initial stress iterative method were employed to simulate the elasto-plastic behavior of geotechnical materials.; The discretisation of the finite element model consists of quadratic finite elements used to model soils, approach slabs, and sleeper slabs. Two-node interface elements are used to allow for separation between the approach slab and the fill embankment, and to allow for separation and sliding between fill embankment and abutment.; Loads are incremented monotonically in small increments and corrective iterations within the increments are performed until equilibrium convergence is achieved.; For each bridge approach investigated, a number of truck load positions are considered, depending on the length of the slab. Maximum normal tensile stress and maximum settlement occurring within approach slabs are collected, along with the longitudinal settlement profiles. The behavior of the various approach slabs are compared with each other. Stress distribution at the abutment reference lines was also considered, both for the case of fixed abutments and for the case of laterally and uniformly displaced abutments. The results show that bridge approaches are significantly affected by embankment fill height, lateral abutment movement, and fill densities. The effects of the above parameters on approach slab lengths are discussed. Recommendations concerning approach slab design are given based on a state-of-the-art literature survey, survey of state highways, and a comprehensive theoretical study. |
