| The "cavity effect" of the composite wall,the insufficient bearing capacity of the floor,and the low-rise in traditional cold-formed thin-walled structure buildings are the important problems that restrict the development and application of this kind of structure.Therefore,this paper introduces the concept of "ring beam and structural column" in conventional masonry structures into the light steel structure system,and proposes a novel assembled weak steel frame-lightweight steel composite wall structural system.Where the weak steel frame can be regarded as the ring beam-structural column in the traditional masonry structure,and the lightweight steel composite wall can be regarded as the traditional brick wall.Through reasonable design,making the weak steel frame and lightweight steel composite wall work together and play their respective performance advantages.In this paper,the seismic behavior and design approach for the assembled steel frame-lightweight steel composite wall structure(SF-LSW structure)were studied using experimental research,numerical simulation,and theoretical analysis.The main contents and conclusions are as follows:(1)Experimental study on SF-LSW structure.Four full-scale specimens of SF-LSW were designed and tested under quasi-static loading.The performance indexes such as failure modes,hysteretic performance,bearing capacity,rigidity degradation,ductility,and energy consumption of the structure were examined,Also,the mechanical mechanism and cooperative performance of the steel frame and lightweight steel composite wall under horizontal load were revealed.The weak steel frame and light steel composite wall had good synergy,and the wall structure exhibited superior seismic performance.The infilled light steel composite wall was damaged earlier than the steel frame,which mainly manifested as the crushing of the corner ceramic concrete,brittle cracking of the sheathing,screw connection failure,and bonding slip failure between the ceramic concrete and wall framing.There was no obvious damage to the steel frames.(2)Factors influencing the shear performance of SF-LSW structure.The numerical model of SF-LSW was established using ABAQUS program.The reliability of the numerical model was verified by comparing the FE analysis results with the test results.The effects of ceramic concrete strength,aspect ratio,stud spacing,steel strength,stud thickness,sheathing type,and wall opening rate on the synergistic force performance of the SF-LSW structure were studied,and the influence laws of different factors were obtained.(3)Study of computational theory for the SF-LSW structure.According to the force mechanism and failure mode of the SF-LSW structure,the composition of lateral stiffness and shear bearing capacity of the composite wall structure was analyzed.And the simplified analytical model of the steel frame and light steel composite wall was proposed,respectively.Based on the simplified analytical model,the calculation methods of the lateral stiffness and shear bearing capacity of the wall structure were derived.By comparing with the test data,it was concluded that the error between the two was small.Indicating that the lateral stiffness and shear bearing capacity calculation formula of the structure proposed in this paper were reasonable.(4)Seismic response analysis of multi-layer SF-LSW structure system.According to SAP2000 FE analysis software,the Kinematic hysteresis model and Pivot connection unit were used to simplify the analysis of the beam-column joints and the infilled composite wall,respectively.Upon this basis,the nonlinear simplified analysis model of the composite wall structure was constructed.A comparison of the analytical results with the experimental data was performed to verify the correctness of the proposed simplified calculation method.Then,a simplified analytical model of the six-story structure was built.The dynamic characteristics and seismic response of the structure were studied.The results showed that the structural integrity was good.Under the action of different seismic waves,each index of the structure satisfied the requirements of the current seismic code.(5)Research on performance-based seismic design method for SF-LSW structural system.In accordance with the experimental study results and corresponding seismic analysis,the seismic discrimination criteria for the SF-LSW structure were classified.Meanwhile,the structural inter-story displacement angle limits were employed as the quantitative index of the structural performance level,and the performance-based seismic design method for the SF-LSW structural system was developed.Finally,the rationality of the proposed seismic design method was verified by an example.The effectiveness of the seismic design method was verified by a six-story SF-LSW structure.The research work in this paper demonstrates the rationality and reliability of the new composite structure system,and provides a basis for the popularization and application of this kind of structure in practical engineering. |
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