Experimental Study On Seismic Behavior Of The Beam-column Sub-assemblies In Different Axial Compression Ratio Of A New Type Of RCS Composite Structure

Based on the known research achievements of RCS composite frame structure from home and abroad,an innovative composite steel-concrete structure named as columns with butt-welded closed compound stirrups and hexagonal honeycombed steel beam RCS frame structure was proposed by the workgroup. Seismic behavior of the beam-column sub-assemblies is still unclear,it is necessary to do more researches on the beam-column sub-assemblies.For the study seismic performance of the beam-column sub-assemblies contain steel plate hoop, after the pseudo-static test on 6 1/2 scale beam-column sub-assemblies of the new type RCS frame structure,it describes the process and phenomenon of the pseudo-static test and the important aspects of affect seismic behavior comprehensively, dissipation capacity and strain data of the beam-column sub-assemblies would be analyzed.Based on the test study, the three linear force-restoring model with negative stiffness are proposed based on linear regression analysis..Following collusions were attained based on test study:(1) Researches show there are two kind of failure mode during low frequency cyclic. One mode is that flexural failure of steel beams, and another is that the welding seam crack between the end-plate of steel beam.(2) Researches show that the specimens failed due to flexural failure of beam have some advantages including high strength, large extension, good seismic capability, while other specimens due to welding cracking have a poor energy dissipation capacity.(3) The ductility decreases with increasing the axial compression ratio.(4) Shear strength of the beam-column sub-assemblies is improved because of lateral deformation of concrete in the joint core is confined effectively the steel plate hoops.(5) Based on the test study, a restoring force model of the beam-columnsub-assemblies in different axial compression ratio of a new type of RCS composite Structure was proposed by research group, and compared with experimental result. It turned out that the curve is in good agreement with it.