碳纤维布加固开裂低配筋混凝土梁试验研究与有限元分析

Experimental study and finite element analysis on cracked concrete beams with low reinforcement ratios strengthened with carbon fiber composite sheets

为了给受损开裂低配筋混凝土结构加固维修提供依据,按3种低配筋率0.127%、0.189%、0.251%设计了6根钢筋混凝土梁。先将混凝土梁加载至出现宽度为0.3mm的可见裂缝时卸载,再粘贴碳纤维布进行加固,养护后重新加载至破坏。试验结果表明:粘贴碳纤维布能有效提高开裂梁的承载能力,随着加固量的增大加固梁承载力提高,但变形能力降低;在低配筋情况下,配筋率越高,承载力提高比例越大。用有限元方法数值模拟碳纤维布加固受损低配筋梁受力全过程,计算结果与试验结果吻合较好,为进一步参数分析提供了工具。

In order to give proposals for strengthening and rehabilitation of cracked concrete beams with low reinforcement ratios,six concrete beams with three different low reinforcement ratios were designed.The beams were preloaded and then unloaded when 0.3 mm wide cracks appeared.The damaged beams were strengthened with carbon fiber composite sheets and reloaded to failure.Testing results showed that the ultimate capacity of strengthened beams increased with the amount of carbon fiber composite sheets,and the larger the reinforcement ratio was,the bigger the increment of capacity of the strengthened beam was,but deformation capacity decreased.The flexural behavior of the strengthened beams subjected to monotonic loads was simulated with finite element method.The calculation results have a good match with test results,which indicates that calculation model can be used in further numerical analysis.