Analysis of Post-tensioned Rectangular and Trapezoidal Box Girder Bridges and its behaviour in Horizontal Curvature Condition

Abstract

Bridge is an important part of any Highway / Infrastructure which helps to connect two major cities /
districts/ towns/ States. Bridge is a key element in any transportation system which provides easy access over physical
obstacles like road, valley, water bodies etc. without closing the way underneath. In recent times with evolution of
Flyovers, Interchanges, Metro rail projects because of which the horizontally curved box girder bridges are widely used
to overcome congested traffic problems and meet complex road alignments. Now the alignment may observe a curvature
hence it is required to include structures in curvature. Hence in this paper, analysis of a two cell post-tensioned
rectangular and trapezoidal box girder bridge is presented by varying radii of curvature(0m, 50m, 75m, 100m, and
125m) using finite element based software(MIDAS). Finite element models were developed for both bridges and for all
radii of curvatures keeping material properties, span, boundary conditions and tendon profiles as constant parameters.
All the models were analyzed for self-weight, including load of wearing coat and crash barrier, and live loads specified
by Indian Road Congress (IRC) namely IRC 70R and IRC Class A loading. Responses in terms of torsional moment,
longitudinal moment, support reactions, displacements, and stresses were determined for developed models and
compared for both bridge sections. Results show considerable difference in the values of torsional moment,
displacements and stresses but with no significant difference in longitudinal moment.