Normal, high and ultra-high modulus carbon fiber-reinforced polymer laminates for bonded and un-bonded strengthening of steel beams
Normal, high and ultra-high modulus carbon fiber-reinforced polymer laminates for bonded and un-bonded strengthening of steel beams
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DOI：
10.1016/j.matdes.2014.11.031
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发表时间：
2015-02
影响因子：
8.4
通讯作者：
E. Ghafoori;M. Motavalli
中科院分区：
文献类型：
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作者：
E. Ghafoori;M. Motavalli
本文研究了普通、高模量和超高模量碳纤维布加固钢梁的有粘结和无粘结两种体系的弹性性能。加固梁的弹性性能为疲劳加固系统的设计提供了有用的信息。共七个钢梁，包括一个控制未加强梁和六个加强梁进行了静态试验，直到失败，在一个简单的支持四点弯曲设置。钢梁由标称杨氏模量范围为165至440 GPa的正常模量（NM）、高模量（HM）和超高模量（UHM）碳纤维增强聚合物（CFRP）层压板进行改造。每种类型的层压板连接到钢梁使用粘结钢筋（BR）和非粘结钢筋（UR）系统。文献中没有BR和UR系统之间的直接比较。本文的主要目的是提供一个更好的了解时，BR和UR系统用于加固梁底翼缘的应力分布沿着。所有样本均因横向扭转屈曲（LTB）而失效。研究了不同加固方法对加固试件屈曲承载力的影响。实验结果表明，使用粘结UHM层压板加固可以增加复合截面的刚度，使得钢型材在屈曲之前屈服，从而实现更大的加固效果。
This paper studies the elastic behavior of steel beams strengthened with normal, high and ultra-high modulus CFRP laminates using bonded and un-bonded systems. The elastic behavior of retrofitted beams provides useful information for design of fatigue strengthening systems. A total of seven steel beams including one control unstrengthened beam and six strengthened beams were tested statically until failure in a simply supported four-point bending set-up. The steel beams were retrofitted by normal modulus (NM), high modulus (HM) and ultra-high modulus (UHM) carbon fiber-reinforced polymer (CFRP) laminates with nominal Young’s moduli, ranging from 165 to 440 GPa. Each type of laminate was attached to the steel beams using bonded reinforcement (BR) and un-bonded reinforcement (UR) systems. There is no direct comparison between the BR and the UR systems in the literature. The main goal of the paper is to provide a better understating about the stress distribution along the beam bottom flange when the BR and the UR systems are used for strengthening. All specimens failed due to lateral-torsional buckling (LTB). The effect of different strengthening methods on buckling capacity of the retrofitted specimens was also studied. Experimental results have shown that strengthening using bonded UHM laminates could increase the stiffness of the composite section so that the steel profile has yielded prior to buckling and a larger reinforcement efficacy was then achieved.