Study on Behaviour of Skew PSC Box Girder Bridge

Abstract

Skew bridges are built where geometry cannot accommodate straight bridge. The most common and basic type of bridge, that is widely used for roadways is Girder Bridge. The two most common types of girders that are used in practice are beam and Box Girders. Though box girder design is more complicated, it has wide acceptance due to their structural efficiency, aesthetic appearance, better stability and serviceability. Over years simple RCC box girders used for short spans resulted in long span prestressed concrete bridges. The use of pre-stressing enables concrete bridge beams to span long distances. Box girders are constructed in single cell, double cell or multicell. Generally bridge with a skew angle less than 20° is designed as normal bridge. If it is more than 20° there is change in the behavior of the skew bridge. Thus Geometry and behavior of skew bridge are affected by the presence of skew angle. The Structural response of skewed bridge to stresses in slab and reactions on abutments can be significantly altered by the skew angle of the substructure. The objective of present study is to compare normal and skew bridge of box girder type, with parameter such as bending moments, shear forces & torsional moments for two span deck slab by considering IRC CLASS AA TRACKED loading. A simply supported two span, two lane PSC slab bridge deck is considered in the present study. The different bridge spans considered are 50m, 60m and 70 m and skew angle is varied from 0° to 60° at 15° interval. The analysis has been carried out using SAP 2000 software.