Seismic Performance Analysis Of Brick Masonry Structure Affected By Acid Rain Corrosion Based On OpenSees

Because of the advantages of local material,simple construction,low cost,good thermal insulation properties,masonry structure has been widely used in office building,residence building,school building and other construction projects,and it represents a larger proportion in all kinds of building structure.However,compared with other structure system,it is brittle material,low strength,heavy gravity and bad integral performance lead to poor performance under seismic action.In addition,acid rain corrosion effect of masonry structure in atmospheric environment cause degradation of material mechanics performance,thus resulting in a decline in the seismic performance of the masonry structure.This article researched nonlinearity of masonry walls affected by acid rain corrosion from masonry component.And through making dynamic incremental time history analysis of masonry structure based on the OpenSees program,the seismic vulnerability curves of different acid rain corrosion degrees masonry structures have been obtained.The results provide the basis for earthquake disaster assessment of the masonry structure.In this paper,the basic composition and application of OpenSees program were made a detailed introduction,and the simulation analysis of masonry structure in the OpenSees program implementation method was mainly researched.In the process of description of all simulation steps,the three key problems which the selection of cross section model,the material constitutive model and cell model were mainly solved.The damage degradation rules of brick masonry structure were research based on the seismic performance test results of brick masonry structure affected by acid rain.Through the fitting analysis to test data of 16 masonry walls of our research group,the bearing capacity and stiffness degradation model of acid rain corrosion walls has been obtained.Based on the existing calculation method about the feature points of skeleton curve and on the statistical analysis to test results of domestic 56 masonry walls,a method for determining the skeleton curve of masonry structure has been get.Then reference to Ibarra-Krawinkler(IK)model hysteresis rules,the masonry member restoring force model has been established.On the basis of restoring force model of good masonry member,the acid rain corrosion degradation model was introduced,and the restoring force model of masonry structure has been obtained.The restoring force model was simulated and validated by OpenSees program.And it is helpful to the seismic performance assessment of masonry structure in service under the action of acid rain environment.On the basis of the traditional equivalent frame model,the modeling method of considering the effect of bending and shearing of masonry structure at the same time was put forward.This method adopts fiber model to simulate axial bending effect of wall and Cross section shear restoring force model based on Ibarra-Krawinkler(IK)model to simulate shear effect of wall.The solid walls,open holes walls and three-dimensional entity structures were selected to make finite element analysis based on OpenSees software.Through comparing with the test results,it has proved that the model for masonry structure seismic simulation has good applicability.Through making incremental dynamic analysis(IDA analysis)to 3-layer masonry structure model with four different acid rain corrosion level by using the equivalent frame model and Open Sees software,then sorting and analyzing the calculated results of software,the vulnerability curves and earthquake damage matrixs of masonry structure with different degree of corrosion has been obtained.So the conclusion that the influence of the corrosion of acid rain effect on seismic performance of masonry structure is great can be obtained.