张弦式预应力CFRP板加固钢-混凝土组合梁的抗弯试验  

Flexure tests on steel-concrete composite beams strengthened with prestressed CFRP plates by string system

作　　者：强旭红[1] 陈龙龙 姜旭[1] QIANG Xuhong;CHEN Longlong;JIANG Xu(College of Civil Engineering,Tongji University,Shanghai 200092,China)

机构地区：[1]同济大学土木工程学院,上海200092

出　　处：《复合材料学报》2022年第11期5135-5147,共13页Acta Materiae Compositae Sinica

基　　金：国家重点研发计划重点专项(2020YFD1100403);国家自然科学基金(52142804,51408150);广东省重点领域研发计划(2019B111106002);中建股份科技研发计划(CSCEC-2020-Z-1);上海市科技计划项目(20DZ2253000);多因素耦合作用下朔黄重载铁路桥梁结构安全监测与状态评估研究(SHGF-18-50)。

摘　　要：为研究张弦式预应力碳纤维增强树脂复合材料(CFRP)板加固方法的加固效果,进行了4根5.2 m长的钢-混凝土组合梁试件的四点弯曲试验。使用自主研发的顶升装置横向张拉CFRP板,配合可转动的端部锚具共同完成加固。试验结果表明:钢-混凝土组合梁均呈现出典型的弯曲破坏特征;加固梁的极限承载能力显著提高,分别提高31.5%、28.8%和47.9%,其中150CFRP(10)-S-C组由于锚具不当而导致CFRP板提前发生破坏;加固对梁的破坏时挠度影响很小,100CFRP(10)-S-C和150CFRP(15)-S-C梁的极限挠度仅降低了0.4%和1.6%;增大CFRP板截面面积对梁的抗弯刚度贡献较大,而提高初始预应力水平更有助于延缓钢梁屈服;加载全过程,CFRP板应力沿全长分布均匀,破坏时材料强度利用率达80%以上。为期约90 h的预应损失监测表明,张弦式加固方法的预应力损失不超过2.5%,且损失预应力补偿方便。但是,值得注意的是该方法对端部锚具的可靠性要求很高。The four-point flexure experiments of four steel-concrete composite beams including three beams strengthened with prestressed carbon fiber-reinforced polymer(CFRP)plates and one non-strengthened as reference were investigated.The CFRP plate was transverse stretched by independently designed string system equipment and fixed on bottom of steel beam by rotatable end-anchorage.Experimental results show that the failure modes of beams present typical bending failure characteristics.The ultimate load-bearing capacities of three beams strengthened with prestressed CFRP plates are significantly improved by 31.5%,28.8%and 47.9%,respectively.Unfortunately,the failure of CFRP plate of 150CFRP(10)-S-C beam due to improper anchorage is premature.The ultimate deflections of 100CFRP(10)-S-C and 150CFRP(15)-S-C are little affected by the reinforcement method,reduced by 0.4%and 1.6%,respectively.The stress distribution of CFRP plate is almost uniform during the whole process,and the material strength utilization ratios of CFRP plates are more than 80%at failure.The prestress losses of CFRP plates after 90 h are not more than 2.5%,and its compensation is convenient.However,it should be noted that this method is highly dependent on the reliability of end anchorage.

关 键 词：钢-混凝土组合梁 预应力碳纤维 增强树脂复合材料(CFRP)板 张弦式 加固 抗弯试验 

分 类 号：TU997[建筑科学—市政工程]