Reliability Identification And Analysis Of Existing Masonry Structures

With the development of economy,the building structures' reliability also arouses wild public concerns except for satisfying the basic usage requirements.1970 years later,many masonry structures have been built in China,in the course of usage,which could be affected by natural disasters and man-made factors inevitably.In recent years,earthquake disasters took place frequently,in order to avoid the collapse of houses to bring people property loss and prolong the service life of the buildings,it is necessary to carry out the reliability appraisals of such buildings in time,acquaint the actual states,and make reinforcement maintenances under the professional guidance.The main contents of this paper are as follows:(1)The development history of masonry structure materials and calculation methods are generalized above all,and then the research status of testing and reliability identification of existing building structures are discussed,which lays a foundation for subsequent contents.(2)The contents of the reliability appraisal of masonry structure are summarized and divided into two aspects,three levels and four grades in following chapters.In combination with the difficulties encountered in the identification process,this paper points out the deficiencies of current reliability appraisal methods and gives some suggestions.(3)In view of the concrete engineering practice,the spot inspections are implemented and which contain the crack detection,the mortar strength detection,the tilt detection,the construction inspection,and the test conclusion.On the basis of the test conclusion,the buildings are appraised at three levels and the reliability appraisal grades are as follows: the overall structure security level CSU level,the usability level CSS level.(4)The static and dynamic analysis of the building structures are carried out by using Ansys software.The static analysis result shows that the structure satisfies the static load requirements.Furthermore,the modal analysis result shows that the first-order natural frequency of vibration of the structure is 1.1586 HZ,the first-order mode is mainly translational,which accords with the dynamic properties of masonry structure.In the time-history analysis,under the action of 220 gal Elcentro wave,the maximum interlayer displacement of the structure occurs at the bottom,the displacement is 0.00822463 m and the maximum interlayer displacement angle is 1/364 which is very close to the collapse limitation of 1/350,the structure is severely damaged and must be reinforced and reconstructed.