A Parametric Study of Bridge Approach Slabs under Vehicle Loads Using SAP2000

Abstract

The transitional zone between a bridge and its adjoining roadway, known as the bridge approach, frequently experiences differential settlement. This study employs the threedimensional finite element software SAP2000 V22 to rigorously examine the performance of bridge approach slabs under vehicular loads, with a particular focus on the interaction between the slabs and embankment settlement. Bridge approach slabs and soil are modelled using shell and solid elements, respectively, with the soil characterized by the Drucker-Prager material model. A comprehensive investigation is undertaken to evaluate the effects of various soil and slab parameters on the system's performance, including slab thickness, slab length, approach slab restriction, fill material thickness, and soil's elastic modulus. Furthermore, a sensitivity analysis considering different boundary conditions is also conducted. The outcomes of the analysis include predicted slab deformations and bending moments under design traffic loads. Notably, a correlation is found between increased settlement and approach slab length at the slab's unrestricted boundary, particularly for soils of lower stiffness. The results also suggest that enhancing the compacted fill material thickness and the soil's elastic modulus can reduce slab deflection. The boundary condition and thickness of the slab are identified as key determinants of settlement values. These findings offer valuable insights for engineering professionals aiming to optimize bridge approach slab design, thereby boosting structural integrity and durability.