Seismic Behavior Research Of Frame-Supported Reinforced Concrete Block Masonry Shear Wall Building

With advantage of saveing soil and energy, and along with forbid to use soil brick gradually within our country, the small-sized hollow concrete blocks have been used extensively as the best new walls material. Medium-hige frame-supported reinfored concrete block masonry shear wall buildings can satisfy the request of the big space in buildings bottom, also have the obviously economic advantage cpmparing to frame-supported concrete shear wall buildings. In order to construct the frame-supported reinfored concrete block masonry shear wall buildings in the earthquake zone, the following aspects of the research were studied in this paper:(1) Adopted the SATWE mold piece within the PKPM calculation software,used equivalent stiffness method, the member force of prototype buildings have been computed. Accordingto design code, the member section and reinforcement of prototype buildings have been established. Based on the similar principle, the member section and reinforcement of prototype buildings have been to convert into 1/4 scale model buildings. The basic mechanics behavior experiment about the material using by model house have been studied. The foundation parameter about the dynamic characteristic of model buildings converting into prototype buildings have been provided. The test results show that the aseismic behavior test research about frame-supported reinfored concrete block masonry shear wall buildings adopted 1/4 scale is reasonable, the model buildings can respond the dynamic characteristic of the prototype buildings completely.(2) Used test substructure for two freedom degree, computation substructure for five freedom degree as whole model buildings substructure pseudodynamic test method, by which the aseismic behavior of frame-supported reinfored concrete block masonry shear wall model buildings was evaluated. Under the Taft earthquake wave( peak value of the acceleration is no bigger than the 125 gal), the Nihe earthquake wave( peak value of the acceleration is no bigger than the 65 gal) and the El-Centro earthquak wave( peak value of the acceleration is no bigger than the 125 gal), the earthquake respond of frame-supported reinfored concrete block masonry shear wall model buildings all were placed in the elastic stage.In the elastic-plastic stage, under the El-Centro earthquake function, frame-supported reinfored concrete block masonry shear wall model buildings have good aseismic ability. The failure model wasthe shear type. The bottom frame-shear was the weak story of the model building. In the peak acceleration 220 gal, the model building just break . In the peak acceleration 600 gal ,the model house arrived the ultimate state. In the peak acceleration 800 gal, the model building was complete breakage.(3) Three story reinforced concrete block masonry shear walls model building pseudostatic test results indicated that the reinforced concrete block masonry shear walls model building attributed to the higher bearing capacity and certainly deformation ability and good collapse resistance capacity. The failure mode of three story model building present to shear-bending type. The influence of axial compression ratio to the bearing capacity and deformation ability was important. Coupling beam is important as consuming energy member. According to the principle of " weak beam of strong wall" on the structure design, reinforced concrete block masonry coupling beam has considerable ductility capacity.(4) The elastic-plastic time-history analysis method was developed to calculating the model building and prototype building. The calculation results indicated that the aseismic behavior of prototype building and the model building was similar. Based on the similar principle, the substructure pseudodyanmic test results can be applide in prototype building. In the aseismic zone with earthquake intensity of 7, under the big earthquake action, .the frame-supported reinfored concrete block masonry shear wall buildings was conducted break . In the aseismic zone with earthquake intensity of 8, the frame-supported reinfored concrete block masonry shear wall buildings can be attained request of code for seismic design of buildings.(5) In this paper,the stiffness ratio( y ) about the second story and the first story in model building test was 4.46. For the sake of developping the deformation ability and consuming energy capacity ,and making the weak layer in the bottom fram-shear layer, ^ = 1.5—4 was suggested. It can make the shear wall quantity not too many, satisfy the request of the big space in the bottom, not lead the deformation concentration in the bottom frame-shear layer, and can avoid the abrupt change of mass and stiffness along perpendicular direction.(6) According to the least energy consumption principle and the failure criteria of orthogonal anisotropic materials, the correlated formula of masonry under combined shear-compression action was established. The three failure models about shear-friction, shear-compression,diagonal compression can be completely expressed with this correlated formula. Matching with considerable experimental data and keeping similar reliability of the current structure design code, the calculation formulaof static shear strength and aseismic strength was set up. The calculation formula is expressed with axial compression ratio as the main variable. The calculation method can uniformly be used by the 'Code for design of masonry structures' and the 'Code for seismic design of building structures' in calculating shear strength. The calculation formula of shear bearing capacity about reinforced concrete block masonry shear walls under eccentric compressed was established.(7) The ductile influence of axial compression ratio,aspect ratio,reinforced ratio and grouted ratio on the shear walls was studied. Displacement ductility design method and elastic-plastic story drift angle allowable value 1/300 of reinforced concrete masonry shear walls was investigated. In the code of our country, The provision of reinforced concrete block masonry shear walls that the axial compression ratio was no bigger than 0.5 was insecurity, the axial compression ratio, no bigger than 0.4, was suggested.