The Collapsed Factors Analysis Of Masonry Structures And Preliminary Exploration About Anti-collapse Based Numerical Simulation

Masonry structure is a typical brittle structure with low tensile, bending, andshearing strength. And it shows the worse seismic performance under the earthquakeaction. Especially under the mega earthquake, masonry structure is easily collapsed. Inorder to improve the action of collapse of masonry structure under the megaearthquake, and to guarantee safety and property of people furthest when theearthquake happened, it is necessary to research and analyse the factors thoroughly,which affect the collapse behavior of masonry structure, and put forward reasonableand effective measures which should be improved the collapse behavior of masonrystructure under mega earthquake, and produce relatively reasonable collapse mode.This paper select the finite element software ANSYS/LS-DYNA as the tool toanalyse the masonry structures. Through designing a typical masonry structure,selecting appropriate material parameters and seting the material failure criteria, finallymaking the masonrysimulation of the structure under seismic action. In this paper, themain content and achieve results are as follows:①In accordance with the existing design specifications and based on a variety ofinfluencing factors to establish typical masonry building,Through comparing it’sperformances under its small, medium, large earthquakes,the comparion results showthat: the rational design of masonry structures in accordance with the existing norms isbasically meet the "minor earthquake, earthquake repair, earthquake inverted"requirements for seismic resistance, in accordance with the norms of rational designpuzzlestructure must ensure that sufficient bearing capacity and must be set to improvethe seismic design; example structure all collapses in the huge earthquake, indicatingthat the seismic behavior of existing norms can not control the structure under theaction of mega earthquakes.②Masonry structure with regular shape, uniform distribution of strength andstiffness displays the failure modes of progressive collapse easily under megaearthquake, the simulation result of the collapse process is shown as: first destructionstarts from the windows, doors and other holes where are in the stress concentration,and with the increase of earthquake effect, the ground floor’s damages intensify untillosing bearing capacity. After the ground floor’s destruction, the upper structure’s crashand damage are following. ③By comparing the similarities and differences of collapse behavior of thecontrast calculation model under mega earthquake with various influence factors (suchas mortar strength, ratio of holes, constructional column, etc.), the conclusion isfollowing: changing factors like mortar strength, ratio of holes, stiffness ratio betweenwall and window wall, height-width ratio, opening holes in the cross wall, can affectthe time that each part of the masonry structure collapsed. Setting of constructionalcolumn can increase the overall deformation capacity of masonry structure and delaythe time of structure collapse, but both of them don’t improve the failure modes verywell of progressive collapse in which way masonry structure usually happens.④Based on the above analysis and synthesis of robust masonry structureresearch，This paper put forward that set refuge unit made of reinforced concrete in themasonry structure to improve the collapse behavior of masonry structure under megaearthquake. And through designing a typical comparative structure demonstrated itseffectiveness.