Experimental Study On Shear Behavior Of UHPC Reinforced Existing Masonry Structures

At present,there are a large number of masonry houses which are lower than the requirements of seismic fortification and code,and these buildings need to be reinforced and repaired urgently.In recent years,a series of guidelines and policies concerning the reconstruction of old residential areas have been issued from the state to the local governments.While these documents have greatly promoted the development of the housing reinforcement market in China,they have also proposed to find a simple and effective reinforcement scheme.Ultra-high performance concrete(UHPC)is a new type of composite building material,which has attracted much attention since it was proposed.It has high compressive ratio,ductility and toughness,etc.,and has a broad prospect in the reinforcement market.In view of the content of the subject research,in situ diagonal shear test under monotone loading and pseudo-static test under low cycle reciprocating load are adopted.In situ diagonal shear test,three groups of 16 single-sided reinforced walls were set according to the grade of M1.0,M2.5 and M5.0 masonry mortar,and the thickness of reinforcement was divided into 20 mm and 40 mm.The failure mode,shear strength,shear strain and shear elastic modulus of the wall were mainly studied.The test group scheme of the pseudo-static test was set according to the results of the in-situ diagonal shear test,and set up 2 groups of 4 single-sided 20 mm thick reinforced walls according to the grade of M1.0 and M5.0 masonry mortar.The seismic performance parameters such as failure history,hysteresis curve and skeleton curve of the specimens under the pseudo-static force were mainly studied.Through in situ diagonal shear test research,it is concluded that for the walls with three masonry mortar levels of M1.0,M2.5 and M5.0,compared with the unreinforced walls,the single-sided reinforcement scheme of UHPC can effectively improve the shear bearing capacity of the walls,delay the cracking of the walls and improve the shear elastic modulus.The pseudo-static test results show that for the walls with M1.0 and M5.0 masonry mortar grades,the use of UHPC reinforcement can effectively eliminate the brittle failure,improve the shear bearing capacity and ultimate displacement of the walls,and improve the ductility,deformation capacity and overall energy dissipation performance of the specimens.Figure 66;Table 14;Reference 76...