Anchorage Length On The Experimental Study Of Steel-concrete Composite Beams Effect Of Improved Stirrup

The coupling beam is the first defensive line for shear wall structure to seismic action. With its good properties it could dissipate large amount of seismic energy to improve the mechanical performance before the share wall damage, while this object could not be achieved in the case of very small span-depth ratio for coupling beams because of the shear failure. Now it is generally considered that the embedded steel plate in beams could be a good solution for this kinds of problems. The embedded length of steel plate into shear wall was extensively studied with structural experiments and computational analysis.Structural experiments for three specimens with span-depth ratio 1.5 were completed. Results show that: the steel plate in concrete beam can not only improve the shear bearing capacity of the beam, but also increase the ductility and the energy dissipation capacity. The anchorage length of steel plate in shear wall could notably affect the damage modes of coupling beams. For small anchorage length of steel plate, it will exhibit good bonding with the around concrete before the beam longitudinal reinforcement yielding, and the strain distribution of the beams meet the plane section assumption. After the yielding of rebar, because of the bending and shear cracking, it seems that the moment for steel plate does not increase, and the anchorage areas begin to distructe before steel plate yielding. For a large anchorage length of steel plate, the bearing capacity is not considerable enhanced relating to the steel plate which has the proper anchorage length. Plastic hinge formed in wall beam interface, the cracks even extended to the inside part of shear wall and lead to serious damage. It is propitious to the arrangement of the rebar in the shear wall and reach a certain economic for a proper anchorage length of the steel plate. At the same time, it can ensure the plate in the beam and meet the capacity requirement.Numerical models for the above three specimens were presented with finite element software ABAQUS. The result is basically in agreement with the experimental result. It shows that: with the increasing of the proper anchorage length for steel plate, the shear capacity of coupling beams could be enhanced.