碳纤维加固二次受力混凝土梁理论计算方法

Theoretical calculation method of carbon fiber reinforced concrete beam under secondary loading effects

为研究二次受力影响下碳纤维网格-聚合物砂浆复合加固梁的抗弯性能,完善其抗弯极限承载力和挠度的计算理论,基于受压区混凝土本构关系,推导出不同破坏模式下碳纤维加固梁的极限抗弯承载力公式,并提出识别加固梁破坏模式的计算判据。按刚度解析法,推导出二次受力下碳纤维加固梁短期刚度计算公式。采用插值拟合法对M-x_(n)、M-β_(1)等二元方程进行处理,应用于不同荷载等级下加固梁的挠度控制验算,规避参数取值问题带来的求解误差。针对不同预载幅值下4根碳纤维网格加固梁进行了抗弯试验,将理论计算值与试验值进行对比。研究结果表明:碳纤维网格加固梁理论计算值和试验值较为吻合,相关计算方法对指导实际工程设计具有一定参考价值。

In order to study the flexural performance of the carbon fiber mesh-polymer mortar composite reinforced beam under the secondary loading effects,and improve the calculation theory of its ultimate flexural bearing capacity and deflection. Based on the constitutive relationship of the concrete in compression zone,the ultimate flexural bearing capacity formula of the carbon fiber reinforced beam under different failure modes was derived,and the calculation criterion of identifying the failure mode of the reinforced beam was proposed. According to the stiffness analysis method,the short-term stiffness calculation formula of the carbon fiber reinforced beam under the secondary force was derived. The method of interpolation fitting was used to process binary equations such as M-x_(n)、M-β_(1),which was applied to the deflection control check calculation of the reinforced beam under different load levels,to avoid the solution errors caused by the parameter value problems. The bending test was carried out on 4 carbon fiber mesh reinforced beams under different preload amplitudes,and the theoretical calculation value was compared with the experimental value. The results show that the theoretical calculation value of the carbon fiber mesh reinforced beam is relatively consistent with the experimental value,and the relevant calculation method has a certain reference to guide the design of actual engineering.