Fragility Research Of Masonry Buildings Based On Improved Capacity Spectrum Method

Masonry structures are widely distributed in China. During the past heavyearthquakes, damage of masonry structures has caused huge casualties and economiclosses. Earthquake damage of masonry buildings varies both in extent and performances.Earthquake damage data shows that even in the same intensity area, the damage degreediffered a lot. The situation of old houses after earthquakes is much more serious thanformally designed buildings. Damage degree of buildings who own more stories ishigher than the lower ones. Large span structures and small wall rate buildings havepoor integrity, which leads to poor seismic performances. Other factors also haveinfluence on earthquake damage degree of masonry buildings.After2008Wenchuan earthquake, the Seismic Intensity Parameter Zoning Map ofChina was modified, the fortification intensity of a few regions were enhanced. The2010new version of Code for Seismic Design of Buildings has modified severalreligious parts of general provisions and construction measurement. Even buildingsbuilt in recent10years have various earthquake capacity impacted by construction years,fortified intensity and other factors. In this paper, according to the lowest requirement ofstories, construction measures and wall rate of masonry structures in Code for SeismicDesign of Buildings of2001and2010version, the author sets several operating dutiesfor FEA (Finite Element Analysis). The operating duties are used for study oninfluences of stories, fortified intensities and wall rates on seismic capacity of masonrybuildings. The main work is shown as follow.1. This paper selects ABAQUS FEA software to build models of masonrybuildings. Pushover method is used on buildings with different fortified intensities,cross wall spacings and stories based on3original masonry buildings. Story drift isadopted to evaluate earthquake damage degree. The influences of stories, fortifiedintensities and wall rates on masonry buildings are summarized and contrastiveanalyzed.2. The improved capacity spectrum method is used to analyze on extensiveoperating duties of three masonry buildings. The uniformed distribution and inversetriangular distribution are adopted. Plastic spectrums are obtained by using strengthreduction model put forward by Zhuo&Fan. Average story drifts under differentintensities are therefore obtained after overlay the capacity curves on the plasticspectrums. The3D surfaces are fitted afterwards and corresponding formulas are fitted.