Fatigue loading characteristic for the composite steel-concrete beams

Abstract

In the last few decades, composite beams, steel I beam, and concrete slab, have had a wide range of usage in bridges construction. This is due to its relatively low economic constructional cost compared to individual steel structures or reinforced concrete structures. This type of bridges in particular and many similar industrial structures in general are repeatedly subjected to fatigue loads, and that is frequently, as a result of the vehicles passing on these bridges or the vibrations caused by the machines in the industrial facilities. Previous investigation of fatigue behavior of composite steel-concrete structures has become ever more important, specially, steel - concrete composite beams. These studies focused mainly on the external structural behavior of these beams such as a load -deflection relation, observing of cracks appeared during the loading and failure stage, and the strain in the steel and concrete flanges. Hence, in this study several factors affecting the mode of failure of these beams under the fatigue loads. ANSYS (Workbench) software package was used to construct a finite element model subjected to cyclic loading, and obtain members’ cyclic behavior at a positive bending moment area. The results of the F.E. analysis were compared with experimental tests to obtain the validity of the finite element model and its accuracy. A parametric study was also conducted to investigate the effect of varying degrees of shear connection on the cyclic loading performance for each part of the composite section.