Retrofitting Method On Collapse Resistant Of Multi-story Masonry With First Story Used As Shops

Due to the advantages such as low cost and low requirement of constructiontechnology, masonry structure has been popular for many years in China and a lotof developing countries. Because of the britle and low strength of material andcrude structural configuration, masonry is more vulnerable to earthquake. So it ishighly significant to take a thorough and broad study to improve the seismiccapacity of masonry structure especially the frame supported masonry structures.Based on large amounts of technical literature both abroad and domestic. Thispaper analyses the typical damage features of frame supported masonry structuresin WenChuan Earthquake and offers a strengthening method. Through shakingtable contrast test，the reinforcement effect is verified.The main works obtained inthis thesis are as follows：Firstly the structure construction and earthquake damaga features of framesupported masonry structures in WenChuan earthquake is analyzed.Ground floorof this kind of building is usually with large space,the main load bearingcomponent at the front is RC column,beam and masonry wall with constructionalcolumn,while the main load bearing component at the back is traditional masonrystructure.More than80%of this type of building collapsed in WenChuanearthquake. Based on the analysis of construction and earthquake damagefeatures，the main cause of collapse is the stiffness difference of the front and theback side.The masonry walls at the back side support much of the horizontalseismic force，and because of its low ductility，the walls collapse first then resultin the fracturing of the whole structure.And then, a retrofitting method to proveductility and balance stiffness is offered,through shaking table test,theearthquake-resistance capacity of three kinds of model,viz standard jointsmodel,bad joints model and reinforced model is compared,The conclusion is thatstandard structural joints may improve the ductility of structures,and decrease theprobility of collapse.By adding wing walls and flanking columns,the non-uniformrigidity of bottom frame is meliorated,and the collapse resistance capacity of thebuildings is improved.At last, in combination with the actual engineeringdemand,this method is used in retrofitting of a multi-story masonry hospital.