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原文传递 Development of Mechanical Strengthening System for Bridge Connections Using Prestressed CFRP Rods

题名：	Development of Mechanical Strengthening System for Bridge Connections Using Prestressed CFRP Rods
正文语种：	eng
作者：	Heydarinouri, Hossein;Motavalli, Masoud;Nussbaumer, Alain;Ghafoori, Elyas
作者单位：	Empa Swiss Fed Labs Mat Sci Ueberlandstr 129 CH-8600 Lausanne Switzerland\|Swiss Fed Inst Technol Lausanne Ueberlandstr 129 CH-8600 Lausanne Switzerland;Empa Struct Engn Res Lab Swiss Fed Labs Mat Sci & Technol Ueberlandstr 129 CH-8600 Lausanne Switzerland;Swiss Fed Inst Technol Lausanne Resilient Steel Struct Lab CH-8600 Lausanne Switzerland;Empa Swiss Fed Labs Mat Sci & Technol CH-8600 Dubendorf Switzerland\|Swiss Fed Inst Technol Dept Civil Environm & Geomat Engn Inst Struct Engn CH-8093 Zurich Switzerland
关键词：	Bridge connections;Carbon fiber-reinforced polymer (CFRP);Finite element (FE);Posttensioned CFRP tendons;Strengthening;Wedge-barrel anchor
摘要：	Stringer-to-floor beam web-to-web double-angle connections are among the most fatigue-prone elements in old riveted bridges. These connections are often designed to carry only shear loads. However, in these elements, fatigue damage occurs because of the out-of-plane deformation of the connections, which is ignored in the original design. In this study, a new retrofitting system is developed to reduce the out-of-plane deformation of the connections using prestressed carbon fiber-reinforced polymer (CFRP) rods. The proposed system consists of a mechanical wedge-barrel anchor to hold the prestressed CFRP rod and a clamping system to attach to the parent structure and to transmit forces via friction. A series of finite-element (FE) simulations was conducted to optimize the size and performance of the retrofit system. Laboratory static pull-off tests were conducted and different failure modes were studied and discussed. A novel test setup (with four supports) was designed for testing the steel connections. The effect of the geometrical imperfections during the installation of the connection was carefully investigated using the FE models and was verified through laboratory the tests. Laboratory fatigue tests were conducted on steel connections with the same dimensions as those in a railway bridge. The designed retrofit system was found to be capable of reducing the stresses at the angle connections by more than 40%. The results of the fatigue tests demonstrated that the designed system could survive more than 11 million load cycles without any fatigue damage or any indication of a loss in the CFRP prestressing level. (C) 2020 American Society of Civil Engineers.
出版年：	2021
期刊名称：	Journal of Structural Engineering
卷：	147
期：	3
页码：	04020351.1-04020351.19