Evaluation of Structural Performance of Bridge Approach Slabs

摘要

Consolidation of foundation soil, compressive deformation of fill materials and erosion of approach embankment often result in significant differential settlement between the bridge structure and the approach pavement. Approach slabs are commonly used to mitigate the uneven surface to enable a smooth transition between the roadway and bridge deck. Despite its extensive use, there is no uniform design of the slab across the US, which may have contributed to their unsatisfactory performance reported in many states. Factors contributing to poor performance include (1) time-dependent consolidation of the natural soil and fill material due to inadequate compaction, (2) poor drainage behind the bridge abutment resulting in erosion of the fill material and void formation under the approach slab, and (3) longitudinal and vertical translations as well as rotation of the abutment causing localized damage at the connection of the approach slab. Distress in the approach slab often manifests itself in the form of transverse and/or longitudinal cracks, which tend to reduce the service life of the slab and increase the maintenance/repair costs.