单 位：
南京林业大学江苏省林业资源高效利用协同创新中心;南京工业大学建筑学院;南京林业大学土木工程学院
摘 要：
由于木材是存在天然缺陷的生物质材料,故木构件在实际使用时存在不可避免的缺陷。已经使用的木结构大都存在开裂、腐朽等损坏现象,其力学性能有所降低,因此木结构需要进行定期修复。木构件的力学性能随缺陷位置不同而产生差异,通过在缺陷梁受拉区底部粘贴轻质高强的碳纤维复合材料(carbon fiber reinforced polymer,CFRP)提高缺陷木梁承载力。通过四点弯曲试验,研究缺陷梁与加固梁的受弯性能与破坏模式,分析缺陷所在不同位置对木梁破坏形态和承载力产生的不同影响。结果表明,受拉区木节对抗弯强度的影响大于受压区木节产生的影响,中性轴处的缺陷导致木梁产生脆性破坏。木梁受拉区有木节时,在底部粘贴CFRP布能很好地起到加固效果,当木梁上部受压区存在缺陷时,破坏由上部缺陷决定,在底部粘贴CFRP布的加固效果不显著。
译 名：
Study on carbon fiber reinforced polymer reinforced timber beams with defects
作 者：
ZHANG Lu;ZHOU Aiping;SHENG Baolu;SHEN Yurong;XU Jianuo;College of Civil Engineering,Nanjing Forestry University;Jiangsu Co-innovative Center for Efficient Application of Forestry Resources,Nanjing Forestry University;School of Architecture,Nanjing TECH University;
关键词：
timber beam;;defect;;mechanical performance;;CFRP;;reinforcement
摘 要：
Wood is one of biomass materials along with natural defects. In other words,there are not wood components without defects in the actual use,and most of the existing wood structures have to be built by using timber with imperfections.Because mechanical properties are reduced due to the components with defects,the safety concerns of the wood structures have been increased in the building material market. To address the concerns,in recent years,the use of carbon fiber reinforced polymer(CFRP) in timber structure has been developed. The CFRP timber is regarded as an economic and effective material due to the enhanced strength and stiffness. The mechanical properties of timber members are different with different defects. The load-carrying capacity of the member can be increased by pasting CFRP in convex side of defective beams. Mechanical performances and failure mode of timber with and without the CFRP reinforcement were examined by 4-point bending experiments. The effect of different defect size and different positions on the failure mode and bearing capacity were analyzed. The test results showed that,no matter whether defects exist in timber,the failure process including elastic deformation,stiffness degradation and failure is nonlinear and progressive. The bending strength values of different failure types caused by the defects are lower than the theoretical values. Compared with the compressive zone,the defect effect on the bending strength in the tensile zone is much greater. The presence of defects in the neutral axis leads to a brittle failure of the timber. The results revealed that,when knots exist in the tension zone,using the CFRP to reinforce beams is highly effective. However,when the defects exist in compressive zone,even the CFRP is pasted at the bottom of beams,the final damage is determined by the defects damage and the reinforcement effect is not significant,which has little effect on reinforcing beams. The bearing capacity increased by using the CFRP to reinforce timber beams,and pasting two layers of the CFRP is better than pasting one layer.
