Cold-formed Thin-walled Steel-bamboo Composite Wall In Application And Performance Research In Low-level Structure

The existing problems of traditional rural residential buildings in China are unreasonable structure design,poor seismic performance,long construction period and high unit energy consumption,to solve these problems,by studying the effect of different types of composite walls with inclined supports on the seismic performance of low-rise cold-formed thin-wall steel structures,this paper optimizes the structural design scheme and proposes the recommended seismic fortification standard,which can promote the application of cold-formed thin-wall steel residential buildings in rural areas.The specific contents are as follows:With the help of ABAQUS software,the modeling analysis and verification of cold formed thin-wall steel and bamboo composite wall is carried out,and the "Embedded" method is proposed to embed the self-tapping screw set between the cladding panel and the steel skeleton model to simulate the connection between various components.The results show that the model can well realise the "pinch-slip" characteristics of the self-tapping screw connection under hysteresis loading.The deviations from the FEM simulation results were within 5%,which were in good agreement.The correctness of the finite element model was verified.Based on the finite element modelling method,six different structural steel-bamboo composite walls with diagonal bracing（including two comparative models of walls without diagonal bracing）were established,and the shear resistance of the composite walls under low circumferential reciprocating loads was investigated finite element.By varying the number,position and orientation of the diagonal braces,the effects of different diagonal brace arrangements on the shear load capacity,stiffness degradation and ductility of the composite walls were obtained.The results shows: With the same number of skew braces,different arrangement has no obvious increase in shear capacity,but has a great difference in structural stiffness.The shear capacity and stiffness coefficient of wall are not significantly increased by increasing the number of diagonal bracing.The "Mi" font layout diagonal support combination wall shear capacity improves 56.4%,"Bing" font layout diagonal support combination wall shear capacity improves 50.2%,their ductility factors improve 0.56 and 1.49 respectively.The shear resistance of the composite wall with 6 diagonal braces connected on both sides of the side column is the best.In this paper,The simplified model of three-story cold-formed thin-walled section steel structure is established by ETABS program,and the shear resistance of the combined wall is simulated by using the simplified calculation idea of multi-segment plastic connection unit Pivot model with reference to the equal substitution tie method.Comparing the simulation results with the test data of the whole structure,the following results can be obtained: The difference between the first-order and second-order frequencies is 9% and 2%,respectively,the time-histories acceleration and displacement curves agree well with the test results.The result shows that the simplified simulation of low-layer curved thin-wall steel structure by using this method is effective and the simulation result is accurate.The influence of different types of slanted bracing walls on the seismic performance of three-story cold-formed thin-wall steel structures is studied by nonlinear time-histories calculation under the conditions of frequent earthquake of 7 ～9 degree and rare occurrence earthquake of 7 ～8 degree.The results shows: For the same working condition,the peak acceleration of the structure without diagonal braces is 12.1% higher than that of the structure with diagonal braces,and the acceleration response is minimum when the wall is arranged with6 diagonal braces on both sides.Under the condition of frequent earthquake,the interstorey displacement angle of the structure with 6 diagonal braces on the wall decreases by 11.25%compared with that of the structure with 4 diagonal braces on the wall,while it decreases by5.6% under the condition of rare occurrence earthquake.It is suggested that the inter-layer displacement angle limit of cold-formed thin-wall steel-bamboo structure system should not be greater than 1/900 in the condition of frequent earthquake fortification,and the inter-layer displacement angle should not be greater than 1/80 in the condition of rare occurrence earthquake fortification.