Study On Mechanical Properties Of T-shaped Full Grouted Reinforced-block Masonry Shear Wall Under Biaxial Horizontal Loading

The full-grouted reinforced-block masonry shear wall structure is a new structural system based on the reinforced masonry shear wall structure,which has good mechanical properties and the advantages of "four sections and one environmental protection",and meets the requirements of green,low carbon,and sustainable development.At present,there are few studies on this structural system,and the existing studies are mostly the proposed static tests when it is subjected to uniaxial horizontal loading,while the building structure is severely damaged by biaxial seismic action under the actual earthquake.Therefore,this paper explores the mechanical properties of the full-grouted reinforced-block masonry shear wall under biaxial horizontal loading utilizing experimental data analysis and numerical simulation and compares the mechanical properties of the wall under uniaxial horizontal loading.The specific research contents are as follows:(1)The quasi-static test data of four full-grouted reinforced-block masonry shear walls under biaxial horizontal loading are analyzed.The influence of horizontal and vertical reinforcement ratio and grouting material on the hysteretic curve and skeleton curve of the wall is discussed.The three-fold line model of the skeleton curve is summarized.The bearing capacity and deformation capacity of the wall is investigated.The stiffness degradation law of the wall is studied,and the stiffness attenuation equation and the normalized stiffness attenuation equation are fitted,which satisfy the exponential attenuation law.The cumulative energy dissipation of the wall is calculated and the range of equivalent viscous damping ratio coefficient is given.Based on the test results,the skeleton curve and hysteretic curve of the wall are obtained,and the Clough restoring force model is proposed for the monolithic masonry wall under biaxial horizontal loading,which lays a foundation for improving the seismic design theory of monolithic masonry wall.(2)According to the size and loading data of the full-grouted reinforced-block masonry shear wall,the numerical model of the wall is established by finite element software Abaqus,and the key steps in the modeling process are discussed.The skeleton curve,load and displacement characteristic values of the full-grouted reinforced-block masonry shear wall were obtained by numerical simulation and compared with the results of the proposed static test to verify the feasibility of the numerical model;the equivalent plastic strain cloud,compression damage cloud,tensile damage cloud and stress cloud of reinforcement of the wall obtained from the simulation were analyzed to reveal the stress change,stress law and damage pattern of the full-grouted reinforced-block masonry shear wall during the loading process.(3)Based on the modeling method that has been verified to be feasible,an expanded parametric analysis of the mechanical properties of the full-grouted reinforced-block masonry shear walls is carried out.The effects of different loading paths,axial compression ratios,displacement cycles,displacement amplitude increments and concrete strength on the mechanical properties of full-grouted reinforced-block masonry shear walls are analyzed,and the effects of different parameter variations on the mechanical properties of the walls were summarized,including: skeleton curve、bearing capacity、deformation capacity、stiffness degradation and energy dissipation capacity.The effects of uniaxial and biaxial horizontal loading on the mechanical properties of full-grouted reinforced-block masonry shear walls were investigated,and the results showed that the mechanical properties of the walls were significantly affected by the changes of parameters under biaxial horizontal loading.