Seismic Vulnerability Analysis Of Masonry Structures Designed According To The Current Codes And The Former Generation Codes

Masonry structure has still been applied extensively in China，however, this kind ofstructure is prone to damage severely in the major earthquake. In2010, Chinapromulgated formally “the code for seismic design of buildings”(GB50011-2010).Subsequently, in2011,“the code for design of masonry structure”(GB50003-2011) hasofficially put into use. It is imperative to find out what are the influences of the revisionof resistance measures for masonry structure exerting on the seismic performance of thestructure and moreover how much this impact matters, which are meaningful researchwork. Seismic vulnerability analysis can, to great extent, convey the ability thataccomplishes a predetermined goal under different earthquake intensity from aprobabilistic sense, which is a significant research means of structural seismicperformance.The main research work of this paper around the problems mentioned aboveincludes:①The comparative analysis of the principal revised contents between the old andthe new code. It chiefly involves the basic principles, including the thought of seismicfortification, the earthquake action and so on, several clauses that embody the basicdesign requirements of masonry structure, seismic checking calculation, seismicstructural measures and so on. Furthermore, aiming at the above contents, the certainanalysis has been carried on.②In the Perform-3D analysis software, it is inevitable to select the appropriatematerial parameters and analysis unit. At the same time, simulation analysis of ashaking table test has been conducted. Analysis verifies that the model parameterselected is effective to simulate the time history analysis of masonry structure.③According to the regulations of the old and new codes, a series of masonrybuildings (11groups) have been designed and afterwards the design results have beeninvestigated respectively. Adopting structural seismic vulnerability analysis methodbased on performance, numerical simulation analysis has been underdone directingagainst example. On the basis of the analysis results, the distinct quantitative indicatorsof masonry building vulnerability analysis have been assessed and the vulnerabilityperformance of masonry structure designed in accordance with the old and new code separately has been compared. Finally, the rules have been summed up and combinedwith differences of two generation code in the design, the causes have been analyzedsimultaneously.Through the study mentioned above, the main results contain:①Both the story drift and deformation-energy damage index are effective toevaluate the damage state of masonry buildings. It is noteworthy that seismicvulnerability analysis employing the story drift as quantitative indicator is more secure.②The new specification strengthens the setting requirement of the structuralcolumn in the structure, especially in the staircase. Therefore the anti-seismicperformances of the structure have been generally improved and the excess probabilitiesof different performance levels in a certain example decrease, among which the excessprobability of collapse prevention level reduces most.③The level of the wall material strength exerts great impact on the minor andmedium damage probability of masonry buildings. The strengthened seismic structuralmeasures such as the structural column could evidently decrease probabilities ofdamage seriously and collapse, which have remarkable effect to improve the collapseresistance capacity of the structure.