Effective Flange Width for Stress‐Laminated T‐System Timber Bridges

Abstract

Stress-laminated T-system timber bridges consist of laminated deck sections combined with glued-laminated timber beams compressed transversely with high-strength steel bars. In the design of these structures, a deck-and-beam T-section is isolated and analysed as a T-beam. This paper presents a regression equation for the computation of effective flange width for stress-laminated T-system timber bridges; a width over which the normal stress can be assumed constant. Using actual dimensions, orthotropic material properties, and AASHTO truck loads, 125 bridge models were analyzed by a special finite element program for general anisotropic shell-and-beam-type structures. The results of the analysis were used to conduct a parametric study followed by a regression analysis to develop a prediction equation for the computation of effective flange width. Simplified equations for the computation of the effective width, which are within current upper and lower bound elasticity solutions, are proposed for use in design.