Experimental Study On Damage Evaluation Method Of Masonry Structures Damaged By Earthquake

Because of its easy materials and low cost,masonry structure is the main form of housing construction in urban and rural areas,and there are a large number of housing stocks.However,in the previous destructive earthquake,compared with other building structure forms,masonry structure suffered particularly serious damage,leading to a large number of casualties and huge economic losses.In recent years,large earthquakes such as Wenchuan and Yushu occurred in China,and a large number of masonry structures were seriously damaged after the earthquake.Therefore,it is of great significance to study the residual seismic capacity of masonry structures damaged by earthquake.In this paper,the brick masonry wall is taken as the research object.Firstly,the pseudo-static test is carried out in the laboratory to compare the different effects of different construction measures on the seismic performance of masonry structure in different versions of codes.The finite element simulation was carried out by ABAQUS to explore the material constitutive and bonding modes suitable for brick masonry walls.The test results are compared with the simulation results to verify the accuracy and rationality of the finite element method.Based on the above research results,a large number of numerical simulations were carried out to study the internal relationship between the wall surface failure(such as crack width)and its bearing capacity under different loads.The main work of this paper includes the following aspects:(1)Code for Seismic Design of Industrial and Civil Buildings(TJ 11-78),Code for Seismic Design of Buildings(GBJ 11-89),Code for Seismic Design of Buildings(GB 50011-2001)and Code for Seismic Design of Buildings(GB 50011-2010)The differences of masonry structural requirements in the four codes were analyzed,and according to these differences,specimens were designed and pseudo-static tests were carried out to compare the stress of masonry walls under the action of earthquakes under the provisions of different versions of the codes.(2)Three kinds of masonry structure modeling methods based on the common finite element software ABAQUS are introduced:integral modeling,separated modeling and discrete modeling,and the application conditions,advantages and disadvantages of the three,as well as the results of the characterization form are discussed.On this basis,an appropriate modeling method is selected and the viscous contact interface model is used for analysis.The crack development pattern is simulated and compared with the masonry structure test.The changes of force and displacement parameters during the cracking process of masonry structure members under load are compared and analyzed,so as to realize the accurate simulation of the apparent damage characteristics and hysteresis characteristics of the brick masonry wall.(3)The parameterized rapid modeling of masonry structure components is realized.The script programs such as defining and endowing material attributes,setting interactions,establishing analysis steps and imposing loads are written using Python language.The GUI interface that can directly input parameters for rapid modeling of masonry structure components and the post-processing program that can extract the width of cracks on the surface of components are developed.(4)For the established brick masonry wall model,a large number of numerical simulations were carried out by changing the height to width ratio of brick wall,reinforcement strength and stirrup spacing inside the constructional column,and the corresponding relationship between the apparent seismic damage characteristics of brick masonry wall(namely the wall surface crack width)and its seismic capacity was proposed.It provides a basis for quantifying the damage state of brick masonry wall under earthquake.