DYNAMIC ANALYSIS OF A FLYOVER BRIDGE

Abstract

A bridge is subdivided into (a) the superstructure, (b) the substructure and (c) the foundation. The bridge deck system is the part of the superstructure directly carrying the vehicular loads. It is furnished with balustrades or parapets, crash barriers, highway surfacing, footpaths, traffic islands, railway tracks on ties, expansion joints and drainage systems. The substructure comprises piers, columns or abutments, capping beams and bearings. The foundation consists of reinforced concrete footings, spread foundations, rafts bearing directly on soil or rock and capping slab supported on piles, wells and caissons. The superstructure of the bridge deck system can be anyone or a combination of the following: slabs, coffered slabs, grids, beams, girders, cantilevers, frames, trusses and arches, cable suspended and cable-stayed. The response of bridges to dynamic or time varying loads is an important area of study in engineering. The bridge structure whose response is sought may be treated as rigid body for shorter spans, and flexible for longer, slender ones.