A feasibility study on the use of low modulus (<125 GPa) carbon fiber reinforced polymer (CFRP) in the retrofitting schemes of structural steel beams subjected to flexural loading is presented. A various CFRP wrapping optimization methods were introduced namely tension flange strengthening and U-wrap strengthening. The result indicates that the strength of the member can be increased significantly by adopting the appropriate wrapping method. A simple theoretical calculation to estimate the design moment capacity of the CFRP strengthened steel member with the nonlinear material properties has been presented. Further, the design stress and strain values recommended in the current design provisions of ACI were validated with the test results and found to be unconservative. Therefore, a method to evaluate the design strain of a strengthened structural steel member using low modulus CFRP has been suggested from the present results. The reliability study based on the limited test results also indicates that the suggested elastic strain design limit state is reliable. For ease of understanding, a design example for predicting the design strength of the steel flexural member strengthened using low modulus CFRP has been provided.

提出了在结构钢梁受弯荷载改造方案中使用低模量（<125 GPa）碳纤维增强聚合物（CFRP）的可行性研究。介绍了多种CFRP缠绕优化方法，即张紧法兰加强和U形包裹加强。结果表明，采用适当的包裹方法可以显着提高构件的强度。提出了一种简单的理论计算来估算具有非线性材料特性的CFRP加固钢构件的设计弯矩能力。此外，ACI当前设计规定中推荐的设计应力和应变值已通过测试结果进行了验证，发现是不保守的。因此，根据目前的结果，提出了一种使用低模量CFRP评估加强结构钢构件设计应变的方法。基于有限测试结果的可靠性研究还表明，建议的弹性应变设计极限状态是可靠的。为了易于理解，提供了用于预测使用低模量CFRP加强的钢挠性构件的设计强度的设计示例。