钢筋混凝土梁加固时的既有荷载对其抗弯性能的影响

模拟实际构件的加固及受力过程,对梁在承受不同荷载作用时外贴CFRP加固进行了抗弯试验和理论分析。试件包括16根外贴CFRP加固梁和2根对比梁。试验参数为:纵筋配筋率、CFRP加固量、粘贴纤维布时持载大小。论文对持载的大小对梁的抗弯性能的影响进行了详细的分析。试验和分析结果表明:采用CFRP加固的钢筋混凝土梁的刚度较普通钢筋混凝土梁的刚度都有明显提高,纤维布对以抗弯为主的构件具有增强刚度、控制挠度的作用。纤维加固时梁所持荷载的大小,对梁的刚度有较大影响,特别是对屈服阶段的刚度影响较大;但对梁的屈服荷载及极限承载力影响较小,可以忽略其影响。论文的试验现象及分析结果都有新颖之处,对相应规范的编制及工程应用有较高的参考价值。

Effect of sustaining load level on flexural behavior of RC beams retrofitted with CFRP sheets

The research reported in this paper is to investigate the effects of externally bonded CFRP sheets on flexural performance of beams subjected to different levels of sustaining load.To this end,a series of 16-RC beams retrofitted with CFRP sheets and 2 control beams were tested,and the theoretical analysis was conducted to explain the experimental phenomena and test results.The experimental parameters include rebar ratio,number of plies of CFRP laminates and sustaining load level at the time of retrofitting.This paper presents a detailed analysis on the sustaining load levels that may have significant influence on the flexural behavior of the strengthened RC beams.Both the experimental and analytical results indicated that the stiffness of all the strengthened beams had been increased evidently as compared to that of the control beams.This phenomenon implies that FRP played an important role to increase the stiffness,thus reduce the deflections of the strengthened beams.The sustaining loads have an obvious effect on the stiffness of the strengthened beams,especially on the average tangent stiffness at post-cracking stage.The experimental and analytical results in this paper are novel,and the findings may be considered for possible adoption into the design codes,also for practical engineering applications.