Prestressed Composite Girders. II: Analytical Study for Negative Moment

Abstract

A method for the structural analysis of prestressed composite steel‐concrete girders was studied in this paper. The deflections, forces in the prestressing tendons, and strains in the steel beam and concrete slab of composite girders were computed throughout the entire loading range up to failure. Equations are provided for the calculation of the yield and ultimate load capacities of the girders. The developed analytical models were based on the incremental deformation method. The results of the analytical study were compared with test results of several girders. Reasonably good correlations between analytical and experimental results were obtained. Also, the results showed that a substantial increase in the yield and an increase in the ultimate load capacities can be achieved by adding prestressing tendons to the composite girders and prestressing them. It was determined that the most effective construction sequence for prestressed composite girders in negative moment regions is to posttension the composite girders with tendons in the concrete slabs.