Study On The In-plane Shear Performance Of Brick Masonry Walls Strengthened With Textile Reinforced Concrete

Many of the existing masonry buildings in China have been built for a long time,and with the increase of service life,a larger part of them do not meet the seismic requirements and need to bestrengthened to improve their mechanical properties.TRC(Textile-reinforced concrete)is a kind of fiber reinforced material consists of continuous multiaxial hybrid fibers embedded in cement-based matrix,which has good load-bearing capacity and has the advantages of light weight,corrosion resistance and strong ability to limit cracks as reinforcement material,and has wide application in the field of masonry reinforcement.In this paper,the in-plane shear performance of TRCstrengthened brick masonry walls is studied,the effects of masonry wall dimensions,the number of TRC layers and the type of fiber are mainly considered.The in-plane shear performance of TRC-strengthened masonry walls is compared with FRP(Fiber reinforced polymer)and ECC(Engineered cementitious composite)strengthened masonry walls.The main tests contents and conclusions are as follows:(1)The in-plane shear performance of TRC-reinforced brick masonry walls is studied,and the results shows that: TRC strengthening can significantly improve the in-plane shear capacity of masonry walls,and the brittle damage characteristics of the masonry walls are improved after strengthening,and the shear strength and ductility are enhanced.The TRC layer has good interfacial bonding with the masonry walls,and no debonding of the reinforcement layer is observed in the test.When the masonry wall thickness is certain,the greater the length and height,the smaller the shear strength,the greater the shear strength increase after TRC strengthening;when the masonry wall length and height are certain,the greater the thickness,the greater the shear strength,the smaller the shear strength increase after TRC strengthening;the more layers of reinforcement in a certain range,the greater the shear strength,but the shear strength is also influenced by the damage mode.The shear performance of carbon-TRC strengthening is better than basalt-TRC.(2)The in-plane shear performance of TRC-,FRP-and ECC-strengthened masonry walls are compared,and the results shows that: TRC and ECC have good interfacial bonding with masonry,while FRP has poorer synergistic force performance with masonry walls.When the thickness of TRC and ECC layer is the same,the shear strength improvement effect is similar,and ECC strengthening is slightly higher than TRC strengthening.When the stegnthening rate is the same,the deformation capacity of TRC-strengthened masonry walls is higher than that of FRP-strengthened walls,and FRP strengthening is also slightly smaller than TRC in terms of shear strength due to the poorer interfacial bonding.Bed joint reinforcement is a strengthening method suitable for enhancing the shear performance of new masonry walls,which can substantially improve the shear strength of masonry walls but has little effect on ductility.All strengthening methods enhance the shear stiffness and energy dissipation capacity of masonry walls to different degrees,but the tests of shear stiffness and energy dissipation capacity has a large variation,which is related to the stress and strain redistribution occurring in the specimens before reaching the peak load related.(3)Based on the collected test data and the data from this test,the in-plane shear capacity of TRC-strengthened masonry walls is calculated using the calculation method from ACI 549.4R.The results show that the calculated values derived from this code are conservative,and suggestions for improvements to the relevant calculation methods are presented.There are 51 pictures,14 tables and 109 references in this paper.