COLLAPSE LOADS OF CONTINUOUS SKEW COMPOSITE BRIDGES

The prediction of the ultimate load capacity of composite skew bridges with stab-on steel I-girders is required for the ultimate limit state design of such bridges. In this paper, the prediction of the most pro bable yield-line patterns of failure under different cases of loadings is presented. The prediction is based on a parametric study (companio n paper) as well as on laboratory test results on simply supported and continuous two-span skew composite bridge models. Good agreement is s hown between the theoretical and experimental results. The results sho w that the skew-angle-bridge-aspect ratio, as well as the type of conn ection between different elements of the composite bridge are the main factors in predicting the collapse load and the failure pattern of th e bridge. The degree of composite action between the diaphragms and de ck slab is also shown to have an influence on the ultimate collapse lo ad of the bridge. A method relating American Association of State High way and Transportation Officials (AASHTO) truck loading to the collaps e load is presented. The derived equations can be readily used for eit her designing skew composite bridges or analyzing existing ones. A wor ked design example is presented.