Optimization Design And Mechanical Behaviors Of Light-Gauge Steel Stud Concrete Composite External Wall Panel

The light-gauge steel stud wall has been widely used in China due to its advantages of light weight,high strength,environment friendly and energy efficiency,etc.However,the light-gauge steel stud walls are mostly used as inner partition walls.The problem of impermeability,thermal insulation,exterior wall decoration and large area window opening has not been well solved when it is used as exterior wall.So,a new form of composite panel was developed in this paper,which is named Light-Gauge Steel Stud Concrete Composite External Wall Panel,hereinafter referred to as SC wall panel.SC wall panel is made of concrete slab,steel studs and fiber cement board,which are effectively connected via shear studs and tapping screws.It is significantly important for composite wall to ensure that the connection of the three compomemts is reliable and the joint between wallboard and frame has a good seismic performance.Thus,experimental research and finite element analysis have been carried out,which can provide key parameters for us in engineering.The specific contents of this paper are as follows:(1)8 groups and 11 groups of specimens were designed respectively for the shear performance of tapping screws and the tensile properties of shear connectors to study the bearing capacity and failure mode of specimens.Test results show that: the shear strength of tapping screw connections is affected by the shear strength of tapping screw and the thickness of fiber cement panel;and the tensile strength of shear connectors is determined by the depth of shear connectors in concrete and the welding quality between shear connector and stud.(2)Two standard wallboard units are designed to considerate the influence of stud spacing.The results of bending test indicate that: the flexural capacity of the SC wall is controlled by the serviceability limit state.The relative deflection corresponding to the peak load can reach 1/98,which is far greater than limit of 1/200 specified by the specification.Under the design wind load,the wallboard is still in the elastic stage which shows excellent bending performance.(3)The finite element software of ABAQUS is used to stimulate the flexural performance of the SC wall panels.Compared with the experimental results,the reliability of the finite element model is verified.The following conclusion can be made by the parameter analysis.The initial stiffness of simulation is slightly larger than that of experiment,but it can simulate the behavior of SC wall accurately when it reaches the peak load after cracking.The flexural capacity of SC wall panels can be improved by 25.4%~29.9% when the air layer is cancelled.While the influence of air layer on SC wall panels with different stud spacing is varied.When the spacing of studs is large,the weakening of air layer is relatively obvious.What’s more,replacing the rock wool with foam concrete can effectively restrict the deformation of the stud.When the thickness of the foam concrete is 80 mm,the bending capacity can be increased by 27.6%.(4)Two full-scale SC wall specimens were tested under low cyclic loading.The results show that: the failure of the wallboard is mainly due to the cracking of fiber cement board and the enlargement of the joist web.There is no obvious damage in the connection area between the wall panel and the steel frame.The wallboard still keeps in elastic stage when reinforced concrete frame structures reach elastic inter-story drift 1/550,the wallboard enter the yield state when multi and high rise steel structures reach elastic inter-story drift 1/250.In reaching the limit value of elastic-plastic inter-story drift 1/50,wallboard can still keep in good condition,and the connection is reliable.There is a “zero stiffness” part in the load-displacement curve of SC wall specimens,and the hysteresis loop is Z-shaped.(5)Impact tests are carried out in the internal and external side of SC walls.Through the tests,the impact energy of the two sides were obtained,the values are 98N?m,980N?m,respectively;the failure mechanism of wallboard under internal and external impact is analyzed.In the end,two standards are chosen to classify the impact resistance of SC wall.(6)According to the experiment and simulation results,some relevant suggestions for design and construction of the SC wall are presented.