FRP(钢绞线)加筋混凝土梁正截面受弯承载力计算

Calculation of Flexural Capacities of Concrete Beams Reinforced with FRP Bars(Steel Wires)

纤维增强复合筋、不锈钢绞线等高强材料作为混凝土梁的受力筋可以充分发挥强度高、耐腐蚀性能好等优点,在土木工程中得到了广泛应用。为了分析此类高强材料加筋混凝土梁的受弯性能,在平截面假定基础上,对混凝土和受力纵筋分别采用混凝土Hongnestad模型和线弹性模型,通过平衡条件,推导了FRP(钢绞线)加筋混凝土梁受弯承载力的计算公式,并与国内外82根简支梁的试验结果进行了对比。研究结果表明:加筋混凝土梁抗弯强度试验值与理论值之比的平均值为1.07,标准差为0.14。建议公式可以较好地计算FRP(钢绞线)加筋混凝土梁的受弯承载力。实际工程构件抗弯截面设计时,建议安全配筋率取1.4倍平衡配筋率,设计截面弯矩取0.625倍理论受弯承载力,以使构件具有足够安全储备。

The use of high strength materials such as fiber reinforced polymer rebars, steel wires as reinforcement for concrete beams can give full play to superiority of high strength and resist- ance to corrosion etc. , and have been widely applied to civil engineering. In order to analyze flex- ural capacities of concrete beams reinforced with this kind of high strength material, this paper is based on the assumption that plane section before bending remains plane after bending, Hongnes- tad model and linear elastic model are separately used for concrete and longitudinal reinforce- ment, the flexural capacity formula of concrete beams reinforced with FRP bars （steel wires） is derived on a basis of the equilibrium condition and contrasted between the flexural capacity ob- tained from the theoretical analysis and that experimentally measured 82 simply supported beams at home and abroad. It is shown that the average and standard deviation of the ratio between ex- perimental and theoretical flexural capacities are 1.07 and 0.14, respectively. The proposed for- mula can preferably calculate flexural capacity of concrete beams reinforced with FRP bars （steel wires）. When the bend section of practical engineering member designed, to make member with sufficient safety reserves, this paper proposes to take 1.4 times of the balanced reinforcement ra- tio for the security reinforcement ratio, 0. 625 times of the theoretical flexural capacity for the de- sign moment.