Three-Level Fire Resistance Design of FRP-Strengthened RC Beams
Three-Level Fire Resistance Design of FRP-Strengthened RC Beams
复制标题
FRP强化RC梁三级耐火设计
DOI：
10.1061/(asce)cc.1943-5614.0000840
复制
发表时间：
2018-06-01
影响因子：
4.6
通讯作者：
Teng, J. G.
中科院分区：
文献类型：
--
作者：
Gao, W. Y.;Dai, Jian-Guo;Teng, J. G.
近年来，外粘接纤维增强聚合物（FRP）体系在钢筋混凝土（RC）构件加固中的应用已被广泛接受。该技术的一个重要问题是加固构件的耐火性，目前还没有一个可以由实践工程师轻松实施的系统设计程序。本文首次提出了frp加固RC梁的耐火设计程序。拟议的程序区分了三个级别（I级，II级和III级）的防火设计，以满足指定的耐火等级。一级设计不设防火层，完全忽略玻璃钢体系；钢筋混凝土梁本身预计将存活所需的耐火期。在另一个极端是iii级设计，在这种设计中，FRP系统和原RC梁需要如此隔热，以至于它们在要求的耐火期内都保持有效。在两个极端之间是二级设计，其中提供了中等水平的防火保温来保护RC梁，而不是FRP系统。Level-I和Level-III设计可以采用作者在前人研究中提出的适当方法来实现。对于二级设计，提出了一种基于所谓的500摄氏度等温线方法的简单设计方法，并使用有限元分析生成的数值数据进行了评估。虽然本文只关注受弯破坏的frp加固RC梁，但所提出的一般框架可以很容易地扩展到其他frp加固RC构件以及frp加固RC结构体系。
The use of externally bonded fiber-reinforced polymer (FRP) systems in the strengthening of reinforced concrete (RC) members has become widely accepted in recent years. A significant concern with this technique is the fire resistance of the strengthened member, for which a systematic design procedure that can be easily implemented by practicing engineers is not yet available. This paper for the first time presents such a procedure for the fire resistance design of FRP-strengthened RC beams. The proposed procedure distinguishes three levels (Level I, Level II, and Level III) of fire insulation design to satisfy the specified fire resistance rating. In Level-I design, no fire insulation is provided and the FRP system is completely ignored; the RC beam itself is expected to survive the required fire resistance period. At the other extreme is Level-III design, in which the FRP system and the original RC beam need to be so insulated that they both remain effective during the required fire resistance period. Between the two extremes is Level-II design, in which a moderate level of fire insulation is provided to protect the RC beam rather than the FRP system. Level-I and Level-III design can be realized using appropriate methods proposed by the authors in previous studies. For Level-II design, a simple design method based on the so-called 500 degrees C isotherm method is presented and assessed using numerical data generated by finite-element (FE) analyses. Although the present paper is concerned only with FRP-strengthened RC beams governed by flexural failure, the general framework presented can be readily extended to other FRP-strengthened RC components as well as FRP-strengthened RC structural systems.