Study On The Mechanical Properties Of The New Thermal-insulating And Load-bearing Prefabricated Composite Wall

Integration of new thermal insulation bearing assembled composite wall(hereinafter referred to as new composite wall)refers to the light steel keel composite wall filled with foam concrete with connectors,the wall body with cold-formed thin-walled light steel keel as main bearing component,the inner side of the wall is directly connected with the cover board with self-tapping screws as the removable formwork,the outdoor side use the connectors to connect the mask board as the disassembly free template,thus forming a wall cavity,after casting foam concrete to form the whole.The new composite wall can control the wall insulation by controlling the length of the connectors,and can meet the load bearing requirements by controlling the section of the light steel keel,thus realizing the dual control concept of heat preservation and load bearing.This paper mainly studies the mechanical properties of the new composite wall:1.Experimental studyIn the test,four pieces of walls DD-1,DD-2,DD-1(D-300)and DD-2(D-400)were loaded by monotonic loading,and two pieces of walls DZ-1(D-300)and DZ-2(D-400)were loaded by low cycle repeated loading.Study respectively casting foam concrete or not and foam concrete density on the new composite wall body resistance to lateral stiffness,the influence of shear bearing capacity and seismic performance,research shows that: after casting foam concrete,the shear bearing capacity of the new composite wall and resistance to lateral stiffness were increased significantly,within a certain range of foam concrete density increases,the shear capacity,resistance to lateral stiffness,ductility of the wall dramatically improved,intensity attenuation slower,the ability of energy dissipation enhanced,seismic performance get better.2.Research on calculation methods of bearing capacity and stiffness(1)Research on the calculation method of the axial compression bearing capacity of the new composite wall: based on the eccentric compression state of the new composite wall,the calculation method of effective section width and stability coefficient of the light steel keel is proposed,so as to obtain the calculation method of the axial compression bearing capacity of the new composite wall;(2)Research on the calculation method of the lateral stiffness of the new composite wall: equivalent inclined bar simplification is carried out for the skin plate and foamed concrete.The formulas for calculating the lateral stiffness by force method and displacement method are derived,and then the equivalent stiffness is modified by the test results,and the formulas for calculating the lateral stiffness of the new composite wall are obtained.The results show that the calculated results by displacement method are in good agreement with the experimental results.(3)Research on the calculation method of the shear bearing capacity of the new composite wall: on the basis of the test,the screw group failure model is adopted to simplify the light steel keel composite wall covered with skin plate,and the light steel and light concrete model and strut-and-tie model are adopted to simplify the new composite wall,thus deriving the practical calculation formula of the shear bearing capacity.After the modification,the calculated results are in good agreement with the test values,the light steel and light concrete model has a higher degree of coincidence.(4)According to the research results,a new composite wall structure design method is proposed,which can be used for reference in design and construction.