型钢混凝土T形梁纯扭及弯扭性能试验研究

EXPERIMENTAL STUDY ON PURE TORSION AND BENDING-TORSION PERFORMANCE OF T-SECTION STEEL REINFORCED CONCRETE BEAMS

为研究型钢混凝土T形梁在纯扭和弯扭作用下的受力性能,以翼缘宽度、型钢含钢率、配箍率、翼缘纵筋直径及弯扭比为变化参数,设计并完成12根型钢混凝土T形梁的纯扭、弯扭静载试验。观察了试件的破坏过程,获取了试件的扭矩-扭率全过程曲线、开裂扭矩和极限扭矩等特征参数,深入分析了纯扭、弯扭作用下不同变化参数对型钢混凝土T形梁抗扭性能的影响规律,揭示了其抗扭破坏机理。结果表明:T形截面梁和矩形截面梁的破坏形态基本一致,其中钢筋混凝土梁呈现为脆性破坏,型钢混凝土梁呈现为延性破坏;T形试件翼缘、型钢和混凝土之间存在相互约束作用,翼缘和型钢大幅增强了试件的抗扭强度和延性;试件翼缘的最优高宽比为2.33;随着型钢含钢率的增大,试件的抗扭强度和延性呈增大趋势,平均提升幅度分别为30.99%、101.14%;试件的极限扭矩随着弯扭比的增大而增大,平均提高了7.86%。最后,提出了型钢混凝土T形梁的开裂扭矩和极限扭矩计算方法,所得计算结果与试验结果吻合良好。

In order to study the mechanical properties of T-section steel reinforced concrete beams under pure torsion and bending torsion,12 pure torsion and bending torsion tests of T-section steel reinforced concrete beams were designed and implemented by considering their flange width,steel ratio,stirrup ratio,flange longitudinal reinforcement diameter,and bending-torsion ratio as variation parameters.The failure process of specimens was observed,and the important characteristic parameters were obtained,such as torque-torsion ratio curve,cracking torque,and ultimate torque of the specimens.The influence of different variation parameters on the torsional performance of T-section steel reinforced concrete beam under pure torsion and bending torsion was analyzed in depth,and the torsional failure mechanism was revealed.The results show that the failure modes of the T-section beam and rectangular-section beam are basically the same.The reinforced concrete beam presents brittle failure,and the steel reinforced concrete beam presents ductile failure.There is a mutual constraint between the flange,steel,and concrete of the T-section specimen,and the flange and steel greatly enhance the torsional strength and ductility of the specimen.The optimum aspect ratio of specimen flange is 2.33;with the increase of steel ratio,the torsional strength and ductility of the specimens increase,with an average increase of 30.99%and 101.14%,respectively.The ultimate torque of the specimen increases with the increase of the bending-torsion ratio,with an average increase of 7.86%.Based on the experimental analysis,the calculation formulas for cracking torque and ultimate torque of T-section steel reinforced concrete beams are proposed.The calculated results are in a good agreement with the experimental results.