Experimental Study On Seismic Performance Of Masonry Inter-window Walls With Structural Columns Under Different Reinforcement Methods Of MRPC

As one of the oldest architectural structures in China,masonry structures account for a large proportion of Chinese village and town architecture.There are many seismic zones in China,so certain requirements are put forward for the seismic performance of masonry structures.The longitudinal wall in the masonry structure has many doors and windows openings of different sizes under the requirements of various functional requirements.Under the action of seismic force,the masonry piers,as the main lateral resistant members in masonry structures,are often the first to be destroyed,therefore it is a topic worth studying of improving the seismic performance of the masonry piers wall.Modified Reactive Powder Concrete(MRPC)is a high-performance concrete material.The material contains two kinds of hybrid fibers,which not only retain the high toughness of the RPC but also appropriately reduce the strength.And by changing its fluidity,the masonry wall can be reinforced by plastering.This method has the advantages of convenient construction operation and good seismic performance.In this thesis,the method of strengthening low strength mortar masonry piers with structural column with Modified Reactive Powder Concrete was proposed.The seismic performance and theoretical analysis of five masonry piers with a heightto-width ratio of 1:1 were carried out,and the influence of MRPC double-sided layers,MRPC single-sided layer,MRPC cross-strip layers and reinforced mortar layers on the seismic performance of masonry piers were studied through pseudo-static test.The main results showed that:(1)Splitting tensile tests were carried out to study the influence of interface treatment methods and concrete strength on the splitting tensile bonding properties of MRPC-NC.The results showed that the splitting tensile strength of MRPC-NC bonding increased with the improvement of interfacial roughness and concrete strength,and the reinforcement could significantly improve the brittle failure of the bonding interface.and these conclusions were applied to the reinforcement of masonry piers.(2)Brittle failure occurred in the unreinforced masonry piers with low bearing capacity,and the failure characteristic was masonry piers damage.The reinforcement of masonry piers basically realized the transfer of masonry spandrels,and artificially achieved the multi-channel goal of seismic fortification.The bearing capacity of the reinforced masonry piers was increased by about 34.14%?78.91% of the unreinforced masonry piers ultimate capacity;Ductility deformation capacity had also been greatly improved,and displacement ductility factor was about twice that of the unreinforced masonry piers.(3)In different MRPC reinforcement methods,the extreme bearing capacity of the crossstrip reinforced masonry piers was the highest,and the energy dissipation capacity was the strongest,although the ultimate damage to the masonry piers fails to realize the transfer to the masonry spandrels,but the masonry piers failure mode was ductile bending damage,which was an ideal form of masonry piers failure mode;The reinforcement effect of single-sided reinforcement and double-sided reinforcement was not much different,but the double-sided reinforcement of MRPC surface layer cracks were less developed,so they failed to give full play to the superior mechanical properties of MRPC.(4)Although the bearing capacity of MRPC reinforced wall was almost the same as that of reinforced mortar layers wall,the ductility deformation capacity was 1.37 times that of the reinforced mortar layers wall.And the thickness of MRPC layers reinforcement were much smaller than the thickness of reinforced mortar layers.Hence the MRPC reinforcement effect was better than that of the reinforced mortar layers wall.(5)The calculation of shear capacity was carried out for the unreinforced masonry piers,MRPC double-sided reinforcement,MRPC single-sided reinforcement and MRPC cross-strip layers.The applicability formulas were proposed.The theoretical value of the calculation were basically consistent with the test value.