WHY APPROACH SLAB SETTLES - HIGHWAY ENGINEERING

In this module the definition of approach slab in pavement is explained with examples. Irrespective of the fact whether its ordinary district road or expressway the approach slabs have the tendency to settle thereby developing a bump. Thus the very purpose of providing an approach slab is being defeated. In this module different types of approach slab settlements were discussed. Generally the approach slab settlements are of two types Global and Local. The combination of Global and Local settlements generates bump at the end of the structure. These differential settlement results in abrupt grade change and discomfort to driver and exerting a potentially excessive impact traffic loading on the abutment. In this module we tried to cover the different possible causes for settlement of approach slab. Generally observed cause are selection of fill material, improper drainage arrangement and position of the approach slab leading to generation of bump at the edge.