Effects Of Open Holes On The Seismic Performance Of Short Leg Shear Wall

Short leg shear wall structure is developed with the development of the shear wall structure. While having the advantages of shear wall structure, it also holds the merits of frame structure. Owing to the comparatively stronger resistance of lateral force as well as the rationality of construction cost, the short leg shear wall structure is widely used in practical projects, especially in the construction of high-rise buildings. Due to the relevant specification stipulating that opening holes in the short leg wall structure is forbidden, researches about the influence of opening holes in short leg shear wall were not done sufficiently. Therefore, this thesis studies the following several aspects about the influence of wall limbs holes in short leg shear wall structure.1. Pseudo static test is given to three short leg shear wall specimen which are 1/2 the size of the real ones. The process of the damage of those specimen, whose holes have different sizes, is detailed under cyclic load. The impact of different hole sizes on structural performance of short leg shear wall is analyzed, such as bearing capacity, ductility, initial lateral stiffness, hysteresis behavior and failure behavior. After research of the influential mechanism of wall hole on bearing capacity of short leg shear wall, the influential principle of hole sizes on the seismic performance of short leg shear wall is attained. The experimental results showed that with the increasing of hole sizes, ultimate bearing capacity and ductility of specimen gradually decline,and the speed of stiffness degradation accelerates. Wall holes will reduce the seismic performance of short leg shear wall, so it is prohibited to open holes in short leg shear wall s.2. By usage of ANSYS structure analysis software, the finite element analysis of the test model is worked out, from which the calculated results are compared with the experimental results. The results show that the finite element calculation model can effectively simulate the actual situation. For further analysis of the influence of different hole position and different axial compression ratio on short leg shear wall, nonlinear computation of the wall limbs holes of short leg shear wall is done, which illustrates that closer the hole position is to the bottom of the specimen, lower the ultimate bearing capacity and ductility will be. In the range of axial compression ratio, with the increase of axial compression ratio, the change of yield load and horizontal ultimate bearing capacity of the specimen of short leg shear wall s with holes is not obvious.3. By the usage of the least square method, comparison of the hysteresis behavior of all specimens is carried out to get stiffness degradation rate under positive and negative loading. At the same time, the fact is found that under the same peak load, every loop stiffness of the yielded specimens produce degradation and every stiffness degradation presents a certain proportion, while every stiffness degradation is not closely related with the peak load but the number of load cycles under the same peak. Thus a stiffness degradation rate coefficient is proposed.4. Wall hole reduces the initial stiffness of short leg shear wall. The folding subtraction of thickness is used to wall segments to conduct an equivalent conversion to short leg shear wall which has holes and to deduce calculation formula of initial stiffness of short leg shear wall.