Skew composite bridges — analyses for ultimate load

Abstract

The ultimate limit state design for composite skew bridges with slab-on-I-steel girders requires a reliable prediction of their ultimate load capacity. In this paper, the results from a yield-line analysis of prototype composite bridges subjected to OHBDC truck loading are presented and compared with the results from a nonlinear finite element analysis of such prototype skew bridges. The favourable comparison between the two sets of results indicates that the collapse loads of skew composite bridges can be reliably and readily predicted by the yield-line method of analysis. Equations useful for the design and analysis of skew bridges are given. The experimental results from five composite bridge models tested to failure verify and substantiate the analyses. Results of the ultimate loads of six other skew composite bridge models with punched-to-failure deck slabs are also shown. A general and simplified method relating OHBDC truck loading to the collapse load predicted using the yield-line analysis is presented. Key words: analysis, bridges, composite, design, failure patterns, finite element, models, skew, yield-line.