The Effect of Interior Stiffeners on the Flexural Behavior of Concrete-Filled Steel Tube Composite Box Girders

Abstract

The composite box girder is a structural element with high torsional stiffness and resistance against flexural loads. A new form of bridge construction is the Concrete-Filled Steel Tubes (CFSTs) linked to composite slabs by steel trusses. In this study, four different kinds of composite box girders linked to steel tubes filled with concrete were analyzed experimentally and numerically while being subjected to flexural loads. The specimens were evaluated when subjected to a focused load at the mid-span. The first model is a concrete-filled tube without stiffeners and was considered the control specimen, the second model is a concrete-filled tube with internal I–shaped stiffeners welded inside the steel tube, the third was filled with T-shaped stiffeners, and the fourth with V-shaped stiffeners. The test results showed that the CFST sections with interior stiffeners gave higher strength capacity and less deflection than the control specimen. The best shape of the stiffeners was the T-shape. The numerical analysis results were in accordance with the test results.