| Steel multi-column sandwich composite wall is a composite component which integrates thermal insulating and load-bearing functions.It possesses a lot of advantages,including simple working process,rapid construction speed,excellent thermal insulation effect,light weight and reasonable economy.Besides,it has broad market application prospect.However,steel multi-column sandwich composite wall is a new type of composite structure so that its mechanical properties are not clear.The main force element of the wall is multi-column,which is obviously different from ordinary frame column,and its mechanical behavior under earthquake is more complex.The main purpose of this paper reveals deeply and systematically the seismic behavior of steel multi-column sandwich composite wall.The failure modes,ductility,hysteretic properties,strength degradation and stiffness of the wall is evaluated through in-depth and systematic experimental research and finite element analysis.The influence of factors such as axial compression ratio,center distance of square steel tube and edge length of square steel tube on the steel multi-column sandwich composite wall with diagonal brace and without diagonal brace,will be also analyzed.Then according to presentation format and influencing factor of the domestic and international standards,the shear capacity calculation method of the wall is fitted.The main research contents and conclusions are as follows:(1)Experimental study on low cyclic loading of steel multi-column sandwich composite wall is made.I-shaped wall,L-shaped wall and T-shaped wall with and without diagonal braces between columns were tested.Six full-scale components were made and their seismic behavior of low-cycle reciprocating load is studied.It is found that the yield load,stiffness,ductility coefficient,ultimate bearing capacity,shear capacity and energy dissipation coefficient of the specimen are improved by diagonal braces between columns and the sectional form of structure under the same axial compression ratio.(2)Finite element meticulous analysis of seismic behavior of steel multi-column sandwich composite wall is conducted.Based of experimental research,the finite element model of steel multi-column sandwich composite wall is established.The steel constitutive model adopts the two-line model.The specimen adopts the boundary-restraint condition that the lower part of model is thorough consolidation and the upper part of model is hinged.Meanwhile,according to the corresponding codes,the initial imperfection is introduced.Compared with the test results,finite element models of I-shaped wall,L-shaped wall and T-shaped wall are reasonable and accurate.(3)Seismic behavior of steel multi-column sandwich composite wall is parametric analyzed.Considering the influence of changes in parameters such as axial compression ratio,center distance of square steel tube and edge length of square steel tube,the influence of various parameters on the seismic behavior of steel multi-column sandwich composite wall is studied on the basis of the finite element model.The results show that the maximum shear capacity of the I-shaped wall decreases with the increase of axial compression ratio.And the axial compression ratio has a great influence on the ductility of the wall with diagonal brace;The change of the center distance of square steel tube has a little effect on the ultimate bearing capacity of the steel multi-column sandwich composite wall;As the increase of the edge length of square steel tube,the change of shear capacity is obvious,which shows that the edge length of steel tube has a great influence on the shear capacity of steel multi-column sandwich composite wall.(4)The shear capacity of steel multi-column sandwich composite wall is studied.the calculation formula of shear capacity of I-shaped wall is obtained by using the intensity superposition theory on the basis of variable parameter analysis.Compared with the experimental and finite element analysis results,the calculation results obtained by the proposed calculation formula are conservative.The maximum error is –35.83%,but its presentation format can provide reference in the following research and application in engineering. |
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