Experimental And Theoretical Study Of Concrete-filled Square Steel Tubular Frame-thin Steel Plate Shear Walls With Bilateral Connections

The concrete-filled square steel tubular frame(CFST)-thin steel plate shear walls(SPSWs) combines CFST-frames which have advantages such as high bearing capacity and good ductility pretty well with thin SPSWs noted for its high lateral-resistance stiffness and stable hysteretic behavior. The CFST-thin SPSWs is a excellent combination which can fully perform structural and mechanical property of both structures, especially applied to high seismic zones and super-rise buildings. For easy to stall pipe facility and avoiding “sandglass” phenomenon of frame columns, the web paltes are set to separate from the vertical boundary elements, forming CFST-thin SPSWs with bilateral connection. This dissertation combines experimental testing and theory analysis to study the seismic behavior and mechanism of CFST-thin SPSWs. The main consequences are as follows:(1) the pseudo-static tests were conducted on a CFST-thin SPSWs with bilateral connection and a CFST-thin SPSWs with four-side connection. The seismic behavior of the both specimens are studied. The results indicate that the testing specimens have stable hysteretic behavior, comparative high stiffness, good ductility and high energy dissipation ability. The specimens have ideal failure mode, that is steel plate walls develop tensile field and dissipate energy after buckling and the structure finally failures because of formation of plastic hinge on the column foot, indicating it is a double-insurance lateral-resistance system.(2) Through the comparison between FE and experimental results, the accuracy of FE modeling is verified. The results indicate that axial compression ratio of columns has a slight effect on bearing capacity, hysteretic behavior and stiffness degradation of CFST-thin SPSWs. The opening ratio has major compact on bearing capacity and hysteretic behavior. Bearing capacity, energy dissipation capacity and stiffness of CFST-thin SPSWs decrease with the increase of the opening ratio, but it has little effect on stiffness degradation.(3) Based on the analysis of mechanism CFST-thin SPSWs with bilateral connection, the formulas concerning the shear force and web thickness of middle beam around opening are presented, and it agree well with results of the numerical modeling which meets the assumption of “weak beam and strong column, and weak web plate and strong frame.(4) A new form of opening of the web plate is put forward and the parameters of this new pattern such as opening dimension and opening style are studied. The additional moment acted on CFST-column by tensile field of thin-SPSWs is obtained. Reasonable opening ratio is given.