Experimental Research On Reinforcement Local Compression Masonry Structure

Masonry structure is a kind of ancient building structure and it is also the crystallization of ancient people’s wisdom and sweat.The masonry structure earliest can be traced back over five thousand years ago.But the safety performance decline significantly or the building is close to the biggest design working life after many years of use and erosion of the current existent building.So masonry stricture reinforcement is a best choice consider of environmental protection and green energy-saving.Flat steel reinforcement of brick masonry walls is a new reinforcement method in this paper and it form a structure similar to ring beam on the top of the old wall.This method is simple,convenient and is easy to install,it also economic.This paper also introduces the connection and specific practice of different reinforced wall which provides theoretical guidance for detailed construction in detail when the flat steel reinforcement method is used in the practical engineering application.Then it introduces the detailed construction procedure and announcement of flat steel reinforce masonry structure in detail.But the research of reinforcement is relatively small specific to local compressive wall,so this paper make a research below:Through the research of 10 walls(including contrast specimen)which reinforced with flat steel under concentrated load,analysis the failure mode of the walls reinforced with flat steel.Through the analysis of load-displacement and load-strain of the walls,then it calculate the value of strength increasing of the walls reinforced with flat steel and put forward the bearing capacity equation.The experimental result shows that:(1)Compared with the normal walls,the bearing capacity and crack resistance of the brick masonry walls reinforced with flat steel under concentrated load is higher.,Also the ductility and the deformation ability increase significantly.(2)The smaller of distance of the horizontal flat steel is,the greater the cracking load is.When the horizontal flat steel is 150mm,the bearing capacity is the biggest and increase by 171.6%than the original.The smaller the bolt pre-tightening force is,the bigger the cracking load is.When the bolt pre-tightening force is 9.9kN,the bearing capacity increase most and increase by 196.8%than the original.The cracking load is the biggest when the plate width is 400mm and the bearing capacity is the largest when the plate width is 450mm.The reinforcement method of plate width is 450mm is the best reinforce composite.(3)Compared with the normal specimens,when the reinforced specimens reach the ultimate bearing capacity,the lateral displacement increase greatly,vertical displacement increase five times than the original ones,cement mortar facing has obvious effect on the improvement of bearing capacity and limit the drum deformation.(4)The ratio of the calculated value and experimental values of local compression bearing capacity of reinforced is 0.97～1.16 and its average value is 1.01.The adjustment to local compression strength increase coefficient of standard is establish in theory and is accord to the experiment values.The calculate formula based on the code can be used to check the specimens design bearing capacity and provides a more reliable theoretical basis.(5)The strain of flat steel is larger where the wall crack,the flat steel at this place is easy to appear yield phenomenon.The constraint ability of flat steel to the wall is very strong,the lacing flat steel’s supporting capacity is very strong and it can delay the horizontal flat steel enter the stage of yield.Also it can improve the working ability with crack and it is useful to improve the specimen bearing capacity.