预应力片材加固负载RC梁受弯承载力分析

Calculation of load-carrying capacity of RC beams externally bonded with prestressed composite laminate under sustaining load

分析有初始弯矩作用时,预张纤维片材粘贴加固混凝土梁中加固材料相对该处混凝土滞后应变或超前应变的计算方法和纤维片材中有效预应力的取值;对预应力FRP粘贴加固梁构成的复合截面,分析各种可能应变组合下的受弯极限状态,给出两大弯曲破坏类型(分别由片材拉断和混凝土压碎引发)的界限判别条件和极限承载力计算表达式.试验分析表明,极限承载力试验值与计算值比值的均值为0.99,变异系数为0.047.

For reinforced concrete beams strengthened with pre-tensioned fiber-reinfored polymer（FRP） laminate under externally sustaining moment, the effective prestress and lagged or advanced strain of FRP laminate compared with the concrete strain at the location of strengthening material are discussed. All possible strain combinations at ultimate limit state of bending are analyzed for composite section of RC beam prestressed with composite laminates. Expressions are put forward to distinguish two modes of flexural failures respectively due to the fracture of FRP and the crushing of concrete. A series of formulas are presented for calculation of corresponding strengths, and their applicability is verified by comparing the predicted results with ones. The ratio in average of experimental results to calculated ones is 0. 99 and the variation coefficient is 0. 047.