Numerical Analysis Of Continuous Collapse Of Frame-Supported Multi-ribbed Composite Wall Structure

With the development of economy,the green reform of the construction industry is particularly urgent.As a new type of energy-saving and ecological housing system,the multi-ribbed composite wall structure has been actively promoted.In recent years,It is common to find the accidents caused by the continuous collapse of the structure.Many scholars have studied the mechanism and performance of the continuous collapse of the structure through a large number of experiments and numerical analysis methods.The existing research mainly focuses on the collapse mechanism of the frame structure and the behavior of the beam-column members and the beam-column joints in the collapse.However,the research on the continuous collapse mechanism and performance of the frame structure with infilled wall and the new multi-ribbed composite wall structure is very limited.In this paper,the frame-supported multi-ribbed composite wall structure is taken as the research object,and the mechanism and performance of the continuous collapse of the frame-supported multi-ribbed composite wall structure is studied by the combination of previous experimental data and numerical simulation.This paper will start from the following aspects:(1)Reading the specifications of continuous collapse of structures about the continuous collapse of structure in various countries,analyzing and comparing the basic principles,analysis methods,design methods and ring breaking criteria of the specifications in various countries,making a detailed interpretation of the demolition component method and nonlinear dynamic analysis method,and completing the theoretical research of continuous collapse of structures.(2)Based on the secondary development interface UMAT of ABAQUS,a large-scale finite element software,the PQ-fiber material constitutive package of Tsinghua University is used and combined with fiber beam element;the finite element model of beam and column is established;based on the constitutive relationship of masonry and the plastic damage model of concrete in ABAQUS,the finite element model of masonry is established by shell element.The accuracy and correctness of the model are verified by the comparison of the test results of plane frame and plane frame-infilled wall structure,and the mechanism of continuous collapse of the structure is analyzed.(3)Taking the plane substructure of the 1:3 scale model of the frame-supported multi-ribbed composite wall structure as the research object,the fiber beam element is used to simulate the beam column components of the outer frame and the rib grid of the structure,and the shell element is used to simulate the masonry.The finite element model of the 8-story frame-supported multi-ribbed composite wall structure is established.Based on the nonlinear static analysis and the nonlinear dynamic analysis of the component removal method;In this paper,the deformation and internal force of the remaining structure under the failure of one story middle column and one story corner column are analyzed respectively,and the results of the two analysis methods are compared.This provides a basis for the simplification of the continuous collapse model of the multi-ribbed composite wall structure in the future,and gives the amplification coefficient for the multi-ribbed composite wall structure,which complements and improves the specification.(4)The effects of the number of floors and spans,the ratio of height to width of beams,span length and the different demolition positions on the collapse performance of the plane frame-supported multi-ribbed composite wall structure are studied respectively.It is concluded that the number of spans has little effect on the collapse resistance of the structure,but the appropriate increase of the number of stories is conducive to the distribution of unbalanced loads,reducing the possibility of component failure.The increase of the ratio of height to width of the frame beam not only improves the ability to resist deformation also improves the storage capacity of the beam's bearing capacity,which is conducive to the collapse resistance of the structure;the structure with equal span length is more favorable to collapse resistance;for the plane structure,the effect of corner column failure is greater than that of the middle column failure,so the bottom vertical load-bearing members of structure should be fasten.(5)Because the initial failure of the structure under the vertical load has a great influence on the collapse of the structure,the anti-collapse measures of the frame-supported multi-ribbed composite wall structure are analyzed based on whether the initial failure of the structure occurs.Before the initial failure,the effect of accidental factors such as fire or explosion on the vertical load-bearing members shall be reduced;after the initial failure,the integrity of the structure shall be improved by pulling the structural members,the redundancy of the structure shall be improved by adding the load-bearing members,the ductility shall be improved by strengthening the seismic resistance measures and strengthening key members to resist continuous collapse of the structure.