Study On Mechanical Behavior Of Castellated Steel-Concrete Composite Beam

The castellated steel-concrete composite beam is a new structural type, it not only has a high stiffness and large load-carrying capacity, but also can save the materials and has advantages of economy and beauty. However, the study of this structure is relatively meager scarce at home and abroad, and the standardized design method have not been develop thus limit the use of actually engineering. Therefore, the mechanical behavior of castellated steel-concrete composite beam under static load has become an important research topic.Our team has carried on a serial of specimens under static load tests to observe failure mode and inquire the ultimate bearing capacity, rigidity, ductility previously. This paperestablishes a finite element model in the software ABAQUS and validates the model with experimental data, the results with each other are coincide well. Based on the model which has been verified, we do a further analysis the mechanical behavior of the castellated steel-concrete composite beam under static load tests, considering the concrete strength, strength steel, the hole shape, the shear connectors, expansion ratio and stiffening rib of beam. We compared to their different mechanics indexs such as the development of stress, the P-f curve, the load and the ductility. Finally, how these inquired parameters are influenced by the concrete strength, strength steel, the hole shape, the shear connectors, expansion ratio and stiffening rib of beam were analyzed and the application relation between the strength of concrete and steel strength are discusses.The results are as follows. When the strength concrete and strength of steel increases, both the yield load and ultimate load increases but the ductility decreases; If the strength concrete and strength of steel is matching, it can increase the bearing capacity of the specimen. Otherwise, brittle fracture and local buckling is prone to happen; The castellated composite beam with hexagonal openings and sinusoid openings is easier to bring out stress concentration, which leads to reduce the ductility.The castellated composite beam with a circle openings and oval openings possess greater the bearing capacity and ductility; The smaller longitudinal spacing of shear connectors, the greater the bearing capacity and ductility. Along with the expansion ratio of steel beam increasing, the bearing capacity increases first and then decreases, and the ductility decreases.The bearing capacity and ductility of castellated composite beam increases after the stiffening rib is added at the steel beam web plate. According to correlative theory, this paper is proposed a simplified calculating formula for the deflection under its normal working condition.