| Short-limb shear wall is one of the most popular forms of structure in high-rise residential buildings. T-shaped sections are widely applied in short-limb shear walls. For traditional T-shaped short-limb shear wall, the concrete in the web crush before tension bars in the flange yield, especially when axial compression ratio is large. So seismic performance of T-shaped short-limb shear wall is poor.Steel reinforced T-shaped short-limb shear wall is a new type of component with shaped steel at the boundary of shear wall web. When it's web is compressed, shaped steel undertake a majority of compressive loading, the concrete is not likely to spall. When the web is subjected to tension, anti-compression capacity of flange can be fully exerted because of the large area of the profile steel. Steel reinforced T-shaped short-limb shear walls are with the characteristic of both steel reinforced concrete members and R.C. members.Steel reinforced T-shaped short-limb shear wall can improve performance of T-shaped short-limb shear wall web effectively, improve its bearing capacity, and solve the problem of reinforcements and concrete distribution. The improvement is more significant for high axial compression ratio. Steel reinforced T-shaped short-limb shear wall is with good seismic performance and better mechanical performance. It will be a widely used structural component.This dissertation completed these following works.(1) Two steel-reinforced T-shaped short-limb shear walls were Designed and analyzed deeply.(2) Low-cycle reverse loading test on the designed shear walls were Carried out, a theoretical analysis of test results of walls is also presented.(3) Performed elastoplastic analysis on 4 traditional T-shaped shear walls and 2 steel-reinforced T-shaped short-limb shear walls, verified the reliability of finite element calculation, and analyzed parameters that affect mechanical performance of T-shaped short-limb shear walls.(4) Spatial bearing capacity analysis on T-shaped short-limb shear walls was performed, the failure plane of traditional T-shaped short-limb shear wall and steel reinforced T-shaped short-limb shear wall was investigated, the rational reinforcement amount and axial compression ratio limit of T-shaped short-limb shear walls was discussed. (5) The shear failure modes of section-reinforced T-shaped short-limb shear walls was studied. The effect factors of shear capacity were investigated by nonlinear finite element analysis. a calculation formulae of shear capacity was obtained based on nolinear regression analysis.Main conclusions are summarized as follows:(1) T-shaped short-limb shear wall with rational amount of shaped-steel reinforcement is with symmetric bearing capacity, higher flexural capacity, better ductility and higher energy dissipation capacity. Moreover, nonlinear shear deformation emerges even when the Section-reinfored T-shaped short-limb shear wall presents flexural failure. So it is necessary to take shear deformation into account in members' deformation computation.(2) The FEA results prove that improvements of concrete and steel bar strength do not improve performance of T-shaped short-limb shear wall web significantly. And the bearing capacity varies severely in two directions. Steel reinforcements at the boundary of shear wall web improved its seismic performance greatly, especially for large axial compression ratio.(3) The N-M failure surface of T-shaped short-limb shear wall is different with rectangular members. So the procedure to analyse the failure surface of rectangular members is inappropriate to simulate the failure surface of T-section members.(4) Increase of steel reinforcements in the boundary of wall web can improve the ultimate axial force of shear wall web, and convert compression failure mode of T-shaped short-limb shear wall from small eccentricity into large eccentricity. The axial compression ratio limit will increase consequently.(5) The shear mechanism of section-reinfored T-shaped short-limb shear wall is dissimilar in two directions. When lateral loading is along the tension direction in the web, a powerful arch formed by profile steel and flange bears the majority of shear. When lateral loading is along the compression direction, horizontal reinforceing bars bear the majority of shear force.(6) The shear failure of steel-reinforced T-shaped short-limb shear wall is with significant ductility characteristics. The characteristics include:yielding of stirrups, intense cracks at the shear wall web, large shear deformation and the crush-stripping of concrete.(7) The shear capacity of steel-reinforced T-shaped short-limb shear wall is low when the web is under compression. So its shear capacity should be calculated in this case. Moreover, the effect of axial pressure should not be considered in the calculation of shear capacity. |
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