Experimental Investigation On Performance Of Comoosite Steel-concrete Beams With Corroded Studs

Steel-concrete composite beam combines steel beam with concrete slab by studs, it has advantage of steel structure and concrete structure, and brings great economic benefits and social effect compared to these two traditional structures. In structural design of our country, we often just consider applicability and security but neglect the problems of durability, which would lead to premature structural failure before the service life and make great economic losses. Therefore it is essential to develop research on durability of composite beam. According to the exist durability problems of composite structures, the variety of the ultimate bearing capacity, bond-slip capacity and influence of corroding studs with electronic accelerating method to mechanical behavior of composite beams were studied.28push-out specimens of two series which had different diameters according to EC4were made, each specimen was corroded to different degree by the electronic accelerating method, static loading tests were performed to obtain the slip curve and ultimate strength. It had been showed that the studs with welding failure had lower ultimate strength, while the studs with shank failure had higher ultimate strength. For shank failure, the ultimate strength increased with the corrosion rate increased when the corrosion rate was relatively small, while decreased linearly with the corrosion rate increased when the corrosion rate was bigger. The diameter of studs had no effect on the influence of corrosion rate to ultimate strength. The shearing rigidity of studs decreased with the increase of corrosion rate.Six steel-concrete composite beams were made and the studs arranged in the pure moment region were corroded corroded by electronic accelerating method. Experimental results indicated that the stiffness of composite beams under hogging moment decreased when the stud corrosion rate increased for the specimens in this study. The bond-slip between the steel and concrete increase with the increased stud corrosion rate. The ultimate strength of steel-concrete composite beams slightly decreases with the increased stud corrosion rate. However, the predictions for uncorroded composite beams using current design method are still conservative compared with test results.Finite element analysis of composite beam was carried out with ABAQUS, the corroded studs with different corroded degrees were simulated by spring element with different stiffness. The analysis results were compared with the test results, it had been showed that the ultimate bearing capacities, anti-slip capabilities, the cross-section deflections and the cross section strains agreed well with the test results.