Theoretical Analysis And Experimental Study On Steel-Concrete Castellated Composite Beams

In recent years, with the accelerated process of urbanization, urban bridge construction in China is entering in a period of prosperity, the type of bridge structure is also becoming more diversified. Steel-concrete castellated composite beam is a novel structural form, with the advantages of economic, aesthetic, lightweight, practical, reasonable mechanical behavior and convenient to build, provides a new choice for bridge girder, has a great project potential. In this paper, based on theoretical analysis and experimental research, study has been made to define the stress calculation method in the elastic stage and the ultimate bearing capacity calculation method in the plastic stage of steel-concrete castellated composite beam under loads,together with some design suggestion.The main research work can be summarized as follows:1. Designed a steel-concrete castellated composite box beam with uniform cross section, for the elastic state and the ultimate capacity of the entire process of static loading test, got the data of elastic state of strain, deflection and other data of the ultimate bearing capacity as well as damage phenomena information.Those are used as the foundation for later study.2. The simplified formulas for computing the stress of the steel-concrete castellated composite beams with circular ribs in the elastic stage are deduced based on the vierender truss theory.Test results shows this formula can calculate the value and position of stress on the edge of web holes well(inaccuracy less than 5%), can calculate the stress distribution patterns and trends, but the calculation result of stress at circular cross section and the center section between holes is not accurate.3. The simplified formulas for computing the ultimate bearing capacity of the steel-concrete castellated composite beams with or without circular ribs are deduced, and then using the formula calculated ultimate bearing capacity of different kinds of work conditions of the test beam.Compared with experimental and ANSYS result, show that:This formula is feasible and safer; in the same capacity case, the steel-concrete castellated composite beam can save 20%-35% of steel than conventional composite beam, if consider the impact of circular ribs,steel can be saved 50%.4. Some emphasis about the design of steel-concrete castellated composite beam in the practical application were discussed, such as the design and production of castellated steel beams, shear connectors, the arrangement of ribs and so on; besides, put forward some suggestions on the practical application.