An efficient modelling approach based on a rigorous cross-sectional analysis for analysing box girder bridge superstructures

Abstract

A novel analysis technique is introduced for efficient modelling of box girder bridge decks. The general three-dimensional equations used to accurately define the deformation of these complex beam-like slender structures are decoupled into a two-dimensional cross-sectional problem and a one-dimensional beam problem through decomposition of the three-dimensional strain field. The two-dimensional cross-sectional problem is solved by a two-dimensional finite element analysis considering in-plane as well as out-of-plane warping displacements of the beam section. This gives an accurate constitutive relationship of the one-dimensional beam problem without making any major assumptions as is often done in usual beam theories. The one-dimensional beam problem is solved by a one-dimensional beam finite analysis and the results obtained are used to recover three-dimensional stress, strain and displacement fields accurately. Numerical examples of box girder bridge deck systems having thin-walled sections are solved by the proposed approach to show its performance.