The Research On The Basic Mechanics Performances Of Masonry And Seismic Behaviors Of Reinforced Concrete Masonry Shear Wall Of Tall Buildings

At current, Reinforced masonry structure is widely used to construct tall buildings in the developed countries such as America, Europe, Japan, New Zealand, etc. Especially in America, Reinforced block masonry shearwall structure can be built the same height with reinforced concrete shearwall structure.The beginning of research on the reinforced masonry of tall buildings was relative late in our country. Courrent reinforced masonry structure is not mature and only used to trial engineerings. Main achievements in this paper from two aspects, one is the basic mechanics performance of masonry, and the other is the seismic behaviors of reinforced masonry shearwall structure of tall buildings, as follows.Based on the classic failure of plane theory and introduced the fuzzy theory, the paper firstly presents that three kinds of masonry failure models under shear-compression loading can be divided into two failure regions, namely, one is the failure region of shear-friction and shear-compression, and the other is shear-compression and diagonal compression. By adopting the weight function to combine the classic failure theory to corresponding failure model, the paper presents the formula of shear strength of masonry and simplifies it. Meanwhile, in view of some questions in calculating masonry shear strength existing in current coeds, the design formulae of the static and seismic shear strength of masonry based on failure region theory is put forward.Through the analysis of compressive experimental study on grouted concrete masonry, the basic mechanic performances parameter of grouted concrete masonry, such as deformation modulus, ultimate strain, stress-stain curve, Poisson ratio and so on, is improved. Meanwhile, by using the Kupfer's failure rule, deformation coordination and equilibrium of static force, the reasonable strength ratio range (1.5~3.5) of grouted concrete to block (fcu/fcb), which will be helpful to the compressive strength of grouted concrete and block into full play, is firstly deduced from the theory.The multi-bays frame-brace model is presented for different shearwall structures, such as different height-width ratio of floor, material, frame-supported and opening, that is improved in the single bay frame-brace model. The application of the model to shearwall structure gives good simulations of the nonlinear behavior under earthquake.According to the domestic and foreign research, five seismic performance levels and their corresponding judgment standards, namely full operation, operation, basic operation, life safety and collapse prevention, are presented. At the same time, by improving the traditional pushover method, the method of combined the modal pushover analysis (called MPA) with capacity-spectrum is presented. The calculating results indicate that the improved analysis method is simple and validity.By using the improved frame-brace model, the improved analysis method of different types of reinforced masonry shearwall in tall building was done. The calculated results show that the reinforced concrete masonry shearwall structure had good seismic deformation capacity and caould satisfy the seismic request of tall buildings in seismic area. Therefore, the height limit value of such structures should be appropriately increased in the current standards is suggested.