The Mechanical Properties Of Cold-formed Thin-walled Steel Skeleton-Flyash Ceramsite Concrete Wallboard Study

The paper reviewed the development policy of China's construction industry,summarized the development status of steel-concrete composite wall panels at home and abroad in recent years,as well as the types of structures,test methods,and theoretical results of various types of steel-concrete composite wall panels.Based on the existing problems of wall materials,a lightweighted,energy-saving,heat-retaining and load-bearing composite wallboard was designed,namely cold-formed thin-walled steel skeleton-flyash ceramsite concrete composite wallboard,and its mechanical properties were studied.The main research contents include:(1)Study the structure of the cold-formed thin-walled steel skeleton-flyash ceramsite concrete composite wallboard determining the composition of the steel skeleton and the best mix proportion of the flyash ceramsite concrete.The composite wallboard is cold-formed and thinned.The outer wall of the steel skeleton is wrapped with flyash ceramsite concrete so that the skeleton and the concrete work together and the integrity is good.(2)Nine groups of cold-formed thin-wall steel-flyash ceramsite concrete composite components were tested.The results show that the components are bonded and anchored,and the load-slip curve changes include non-slip,linear slip,nonlinear slip,descending,and converging segments,component bond stress varies negatively exponentially along the anchorage length.The lateral hoop rate increases the ultimate bond load,and has little effect on the initial bond load.With the increase of the number of openings,the initial bond load and the ultimate bond load increase gradually.As the length of the anchorage decreases,the initial bond load and the ultimate bond load increase gradually.(3)For the seven sets of composite wallboard specimens,axial compression and bias mechanical properties were tested respectively.Experimental results show that:the external cladding of flyash ceramsite concrete in profiled steel skeleton greatly improves the compressive strength.The ultimate bearing capacity of the axialcompression wallboard,the biased 25 mm wallboard and the biased 50 mm wallboard are 1417.31 kN,1150.96 kN and 697.57 kN,respectively,which are decreased by18.7% and 39.4% respectively compared with the axial compression wallboard,corresponding to the limit displacements which are 6.42 mm,5.88 mm,5.78 mm respectively.(4)The ABAQUS finite element software was used to simulate the axial compression and bias performance of the composite wallboard.The simulation results were in good agreement with the experimental results.The theoretical analysis,experimental and simulated data were used to derive the formulas for the axial compression capacity,bias bearing capacity and stiffness of the composite wallboard.(5)Using ABAQUS,this paper established seven groups of full-scale wallboard models.Under the effect of horizontal reciprocating loads,the wallboard models with different height-width ratios and thicknesses have good mechanical properties,and the hysteresis curve is plumper with high energy consumption.With the increase of the height-width ratio and thickness,the ultimate bearing capacity increased.The stiffness degradation curves of each model include rapid decline,slow decline,and convergence.In this paper,the mechanical properties of the cold-formed thin-walled steel frame-flyash ceramsite concrete composite wallboard were fully tested and analyzed by finite element analysis,and useful conclusions were obtained.The theoretical analysis and practical applications of this type of wallboard have a high instructional significance.