Experimental Study On Out-of-Plane Punching Shear Resistance Of Double Steel Plate Concrete Wall

The double steel plate concrete composite wall is composed of outer steel plates,core concrete and shear connectors.The two steel plates are connected by shear connectors to form a constraint on the concrete.At the same time,the concrete and shear connections prevent premature buckling of the outer plate.This kind of composite component has the characteristics of simple structure,convenient installation and excellent seismic performance,etc,and is especially suitable for buildings that require high seismic resilience.In recent years,the research on the double steel plate concrete composite wall mainly focuses on the type of connections and the in-plane mechanical performance,all the while the research on out-of-plane mechanical performance,especially the punching shear performance,is insufficient.In this study,experiments and analyses are carried out to study the out-of-plane punching shear performance of a new type of double steel plate concrete composite walls connected by channel steel connectors.The main research contents and conclusions are as follows:(1)An out-of-plane punching shear test was carried out for a new type of double-steel concrete composite wall with channel steel connectors.Thirteen double steel plate concrete composite walls were designed based on the thickness of the steel plate and the distance between channel steel connectors.The walls were simply supported on the four sides.The test results show that the speicmens present three types of load-deflection relationship due to the variation of the distance of channel steel connectors and loading area.The load-deflection curve generally has two bearing capacity peaks and is represented by four or five working stages,namely,the elastic stage(or nonlinear development stage),the bearing capacity degradation stage after the first peak,the strengthening stage,and the final bearing capacity degradation stage.The punching shear failures of core concrete and steel plates correspond to the first and second peak values,respectively.(2)The finite element software ABAQUS was used to simulate the experimental specimens.The shell element was used to represent the steel plate and channel steel connector,and the solid element was used to model the concrete.The generalized contact was defined,and the load-deflection curve was obtained by monotonic pushover analysis.The analytical results were in good agreement with the test results.This model is then used to conduct the parametric analysis with respect to different steel plate thicknesses and distance between channel steel connectors.The analysis results show that increasing the thickness of steel plate can improve the out-of-plane shear resistance of double steel plate concrete composite wall,especially after the first peak,while increasing the spacing of channel steel connectors significantly reduces the peak load.After increasing the loading area,the failure mode of the wall is changed from local punching shear failure to the global bending failure.(3)This study analyzes the mechanism of anti-punching shear outside the double steel plate concrete wall,derives the design formula of the punching shear bearing capacity of the double steel plate concrete wall with channel steel connectors.By referring to the calculation formula in Chinese code ‘Combined Structure Design Specification(JGJ138-2016),’ and the calculation formula of the punching shear bearing capacity of large head bolts in Appendix D of the ACI318 concrete structure specification of the United States,the punching shear bearing capacity of concrete and two steel plates are calculated respectively.Then according to the measured punching angle,the area of the cut-off steel was calculsated.Referring to the previous research results,the punching shear bearinging capacities of concrete,steel plates and steel connectors are combined by a safety factor method.The derived formula is able to predict the two peak carrying capacities,with the error not more than 15%.