Study The Influences Of Masonry Structure Window Belly Wall Damage For Seismic Performance

In China, the damage of window belly wall is a common phenomenon in all previous earthquake damage. However, according to the seismic code of our country, there is no specific method of seismic calculation for window belly wall. Therefore, it is necessary to study the earthquake damage mechanism, damaging factors and the influence for seismic performance.Based on the relevant research results of masonry structure window belly wall,this paper summarized the damage forms and influence factors of masonry structure window belly wall under seismic effect and analyzed the influences on seismic performance under the effect of these factors.This paper studied the material properties and constitutive relations of masonry structure, and identified the material parameters which needed in this paper study.In this paper,a series of numerical examples are designed according to the actual damage of window belly wall, and the influences for earthquake damage mode of masonry structure window belly wall was simulated by using software of finite element analysis ABAQUS.Through the damage figures of masonry structure window belly wall under under earthquake action which simulated by the analysis software,the failure modes of window belly wall were confirmed under different influence factors.Some results in this paper are as follows: In seismic design,in order to making window belly wall damage earlier than window pier wall, controlling the ratios between height of window belly wall and width of window pier wall will be easier, more intuitive, more accurate than the stiffness ratios between window belly wall and window pier wall.Through the value of the span-depth ratio reduced gradually, the failure pattern will change from both ends to X. And the two ends of window belly wall will be damaged earlier and disable the window belly wall when the value is too much; on the contrary, the window pier wall in the bottom layer will be damaged when the value is too little. So, the moderate value of span-depth ratio for window belly wall should be suggested, it will be 1.2~1.5. In the end, this paper simplified the analysis model of masonry structure using the wall-frame analysis method. The inequality which window belly wall damage earlier when designing seismic structure was deduced by referencing the control formula of the theory that the window belly wall damage earlier than window pier wall and the control formula was been made up combining the seismic design. Then verify the accuracy and rationality of software simulation by this inequality.According to the research in this paper,we should make the window belly wall damage earlier than window pier wall through selecting the value of these influence factors reasonably in seismic design. The seismic fortification goal of multi-defense system for seismic structure will be realized if we make window belly wall as the first line of defense.In this paper, the research results made up for the deficiency of the seismic code and provided the reference for related research.