一种分析型钢混凝土T形柱双向压弯受力性能数值模拟方法：试验验证与极限承载力分析

为研究型钢混凝土T形柱双向压弯受力性能，提出一种基于OpenSees零长单元并考虑加载角度影响的高效数值模拟方法，采用该数值算法对已有文献有关弯曲型破坏的型钢混凝土T形柱进行全过程受力分析，以此验证该数值模拟技术的合理性。在此基础上，深入分析轴压比、加载角度、混凝土强度、型钢配钢率与强度、肢高肢厚比等变化参数对型钢混凝土T形柱极限受弯承载力的影响，并推导型钢混凝土T形柱双向受弯承载力计算公式。结果表明：在界限轴压比范围内，提高轴压比、混凝土强度、型钢配钢率、型钢强度和肢高肢厚比均能提高型钢混凝土T形柱极限受弯承载力；但当轴压比大于界限轴压比时，提高轴压比和混凝土强度反而降低其极限受弯承载力；型钢混凝土T形柱的薄弱加载方向为90°（即沿翼缘方向）；加载角度和混凝土强度对型钢混凝土T形柱的界限轴压比影响显著，当加载角度为45°时，其界限轴压比最高；提高混凝土强度会降低其界限轴压比；轴压比在0～0.4、0.4～0.9、0.9～1.4之间，型钢混凝土T形柱双向受弯承载力关系曲线分别为矩形、椭圆形和菱形。

A numerical simulation method for analyzing the biaxial compression-bending behavior of steel reinforced concrete T-shaped columns: experimental verification and ultimate capacity analysis

In order to investigate the biaxial bending behavior of steel reinforced concrete T-shaped columns, an efficient numerical simulation method using ZeroLength element in OpenSees was presented. Steel reinforced concrete T-shaped columns with bending failure mode were calculated by the proposed method. The simulation results agreed well with the test results. The effects of axial compression ratio, loading angle, concrete strength, steel ratio, steel strength and ratio of limb height and limb thickness on the ultimate flexural capacity of steel reinforced concrete T-shaped columns were analyzed. The results show that the flexural capacity of steel reinforced concrete T-shaped columns can be improved by increasing axial compression ratio, concrete strength, steel thickness, steel strength and ratio of limb height and limb thickness when the axial compression ratio is within the range of limit axial compression ratio. However, if the axial compression ratio is out of the limit, the increase of axial compression ratio and concrete strength lead to the decrease of the flexural capacity of columns. The weak loading direction of T-shaped columns is 90° (the direction along the flange). When the loading angle of columns is 45°, the limit axial compression ratio reaches its maximum value, and the limit axial compression ratio may be reduced by increasing the concrete strength. When the axial compression ratios are in the range of 0～0.4, 0.4～0.9 and 0.9～1.4, respectively, the relation curves of biaxial flexural capacity of steel reinforced concrete T-shaped columns shall be rectangle, oval and diamond, respectively. Moreover, computational formulas of the biaxial flexural capacity of steel reinforced concrete T-shaped columns were derived with different axial compression ratios.