一、钢筋混凝土纯扭构件的抗裂度及极限承载力的计算 (1)纯扭构件的抗裂度受纯扭构件的抗裂度是指构件即将开裂时所能承担扭矩的能力。对于素混凝土受纯扭构件在出现第一条裂缝时,几乎同时就发生脆性断裂,所以其开裂时扭矩近似破坏时扭矩。影响素混凝土纯扭构件抗裂度的主要因素为:截面尺寸愈小,构件的极限扭矩系数M_(Thf)~3/R_LW_T值愈大;截面的高宽比越大,其极限扭矩系数值越小,M_(Thf)~3为素混凝土实测的开裂时扭矩,W_T称为理想的塑性抗扭抵抗矩,取W_T=(3c-d)d~2/6,R_L称为混凝土的试件抗拉强 1. Calculation of crack resistance and ultimate bearing capacity of pure concrete torsion members of reinforced concrete (1) Crack resistance of purely torsion members The crack resistance of purely torsion members refers to the ability of the member to bear the torque when it is about to crack. When the first crack occurs in a purely torsion member of a plain concrete, brittle fracture occurs almost at the same time, so when the cracking occurs, the torque is approximately destroyed. The main factors affecting the crack resistance of plain concrete torsion members are: the smaller the cross-sectional dimension, the larger the ultimate torque coefficient M_(Thf)~3/R_LW_T of the component; the larger the aspect ratio of the cross-section, the higher the ultimate torque coefficient. Small, M_(Thf)~3 is the measured cracking torque of plain concrete, and W_T is called the ideal plastic torque resistance moment, taking W_T=(3c-d)d~2/6, and R_L is called the concrete’s specimen resistance. Strong