Reaction Distribution in Highly Skewed Continuous Steel Girder Bridge

A field live load test and a finite element method (FEM) analysis performed on an existing 60° skew, three-span continuous steel girder bridge are presented. The live load testing program with nonstandard truck load was carried out to allow for assessing the adequacy of existing structures and pier support to carry an HS25 standard load. In particular, it was of interest to evaluate the effect of bridge skew on the distribution of reaction forces at interior piers. The measured bridge response under the live load was used to develop and calibrate a FEM model by using the ANSYS computer program. The calibrated FEM model was then used to predict bridge response under an HS25 load. For all load cases investigated, the FEM results showed that distribution of vertical reaction forces on the interior piers was nonuniform. The analysis results indicated that higher reaction forces were experienced by piers on the side of the bridge closer to the obtuse corner than on the side near the acute corner. The importance of using actual field measured test data to develop and calibrate a realistic FEM model is demonstrated.