Comparative Study of Wide Deck Box Girder Bridge Superstructures

Abstract

Abstract: Box Girder superstructures are most popular type amongst all other type bridge superstructures and are extensively used. Nowadays to provide better riding quality and in order to reduce number of substructures and foundations for more clear space underneath, long span continuous or integral type bridge superstructures are preferred. For longer span bridges to reduce dead load and to utilize material to its capacity cellular sections are the most efficient sections in this regard. Box girder is one of the cellular sections. In metropolitan cities one of the restrictions is the availability of land to widen the existing roads. Present trend is to use wide deck bridge superstructure to utilize surface level and elevated level space more efficiently. Bridge aesthetics are also important as bridges are located in metro cities, tourist’s places. In wide deck bridges, ribbed cantilever slab or cantilever with supporting struts are used to impart transverse stiffness while further reducing dead load of the superstructure deck. Three different types of box girder superstructures are studied to inspect their behaviour in longitudinal and in transverse direction. Analysis of three different types of box girder superstructures has been carried out using software CSI SAP2000 and analysis results are presented and compared. In this parametric study various parameters of mechanical behaviour such as deflection, shear lag, effects, bending stresses in transverse direction are compared. Keywords: Box girder, Cellular sections, mechanical behaviour, shear lag, Bridge aesthetics