为考察轴压比、截面形状、配筋情况对异形柱抗扭性能的影响,对9根混凝土异形柱在压力和扭矩共同作用下抗扭性能进行研究。试验结果表明:轴压比对钢筋混凝土异形柱的抗扭性能影响较大,异形柱的开裂扭矩和极限扭矩随轴压比的增加而增大。轴压比为0.189和O.314的L形柱的开裂扭矩较轴压比为0.063的提高了23.7%和74.O%,极限扭矩提高了14.2%和38.7%。轴压比为0.314的T形柱的开裂扭矩和极限扭矩较轴压比为0.189的分别提高了71.0%和16.0%。配置钢筋能显著提高素混凝土异形柱的开裂扭矩、极限扭矩和极限扭转角。轴压比为O.189的配筋L形柱、T形柱和十字形柱较相应的素混凝土异形柱的开裂扭矩分别提高了40.8%,18.9%和26.2%;极限扭矩分别提高了102.0%,106.1%和63.9%;极限扭转角分别提高了486.1%,469.4%和494.0%。轴压比、横截面面积和配筋率均相同时,异形柱的开裂扭矩从大到小依次为L形柱,T形柱,十字形柱。十字形柱和T形柱的极限扭转角较L形柱大34.6%-44.3%。
Nine concrete columns with special-shaped cross section were tested under the pressure and torque to investigate the effects of axial load ratio, sectional shape and steel arrangement on the torsion behavior of specimens. The experimental results show that the axial ratio has significant effect on the torsion behavior of special-shaped columns. The cracking torque and ultimate torque of special-shaped columns increase with the increase of axial load ratio. With the increase of axial load ratio from 0.063 to 0.189 and 0.314, the cracking torque of L-shaped columns are increased by 23.7% and 74.0%, the ultimate torque of L-shaped columns are increased by 14.2% and 38.7%. With the increase of axial load ratio from 0.189 to 0.314, the cracking torque and ultimate torque of T-shaped column are increased by 71.0% and 16.0%, respectively. The cracking torque, ultimate torque and ultimate torsion angle of special-shaped colunms can be significantly increased by the arrangement of steel bar. Compared with plain concrete columns with an axial load ratio of 0.189, the cracking torque of reinforced concrete L-, T-, and +-shaped columns are increased by 40.8%, 18.9% and 26.2%, the ultimate torque of reinforced concrete L-, T-, and +-shaped columns are increased by 102.0%, 106.1% and 63.9%, the ultimate torsion angle of reinforced concrete L-, T-, and +-shaped columns are increased by 486.1%, 469.4% and 494.0%. When the axial load ratio, cross sectional area and reinforcement ratio are just the same, the cracking torque of columns with differently-shaped cross sections decreases in the following order: L-shaped column, T-shaped column, +-shaped column. Compared with L-shaped columns, the ultimate torsion angle of reinforced concrete +- and T-shaped columns are increased by 34.6%-44.3%.