复合加固圆形木柱轴心受压承载力计算

Calculation of Axial Compressive Bearing Capacity of Composite Strengthened Circular Timber Column

内嵌钢筋外包纤维布的复合加固方法可以有效提高古建筑木柱的受压承载力和变形能力,大幅提升其工作性能。为提出内嵌钢筋外包碳纤维增强复合材料(carbon fiber reinforced polymer,CFRP)布复合加固圆形短木柱轴心受压承载力的计算公式,本文共完成12组42根复合加固试件的轴心受压试验。试验结果表明:木柱的破坏主要发生于初始缺陷较为集中的区段,且复合加固方法能够提升木柱的承载力和变形能力,加固效果显著。基于经典的纤维布约束混凝土柱抗压强度理论,对CFRP布约束木柱相关试验数据进行拟合分析,进而提出3个CFRP布约束木柱的抗压强度计算模型。通过对比理论计算值与试验值,比选出适用的CFRP布约束木柱顺纹抗压强度计算模型,继而给出复合加固圆形木柱的轴心受压承载力计算公式。依据补充试验结果和与既有文献研究中试验数据的对比可知,理论计算能够较好地预测相关试验结果,从而验证复合加固圆形木柱轴心受压承载力计算公式的可靠性。

The composite strengthening method with near surface mounted steel bars and wrapped fiber reinforced polymer strips can improve the bearing capacity and deformation behavior of timber columns effectively,and enhance their working performance greatly.To propose the load-bearing capacity formula of short timber columns strengthened with near surface mounted steel bars and wrapped carbon fiber reinforced polymer(CFRP)strips,a total of 42 reinforced specimens(12 groups)were tested under axial compression.The test results indicated that the failure of timber columns mainly occurred where the initial defects concentrated,and the bearing capacity and deformation performance of timber columns could be improved through the composite strengthening,showing significant strengthening effectiveness.Based on the typical strength model of concrete columns wrapped with fiber reinforced polymer strips,three strength models of timber columns with wrapped CFRP strips by analyzing and fitting the relevant experiment data were proposed.Through the comparison between theoretical and test values,the feasible strength model for the calculation of timber columns confined by CFRP strips was selected,and then the calculation formula of bearing capacity for the circular timber columns with composite reinforcement method was obtained.According to the additional experiment results and the comparison calculation for test data in existed research,it can be obtained that the theoretical calculation was able to predict the test results,which verified the reliability of the formula for the calculation of the strengthened timber columns’load-bearing capacity.