Structural Assessment of Externally Strengthened Bridge Deck Panels
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Structural Assessment of Externally Strengthened Bridge Deck Panels Jongsung Sim & Hongseob Oh & Christian Meyer
Received: 2 June 2005 / Accepted: 5 April 2006 / Published online: 31 May 2006 # Springer Science + Business Media, Inc. 2006
Abstract Deteriorated concrete bridge decks are strengthened with external bonding technique using either steel plate or various FRPs to enhance the decreased load carrying capacity and serviceability. But the failure characteristics of bridge decks strengthened with various materials can be changed according to mechanical properties of strengthening materials or strengthening scheme as well as the strengthening amount. In this paper, strengthening effect of deck strengthened with carbon fiber sheets, glass fiber sheets or steel plates is compared. And the theoretical load carrying capacity are evaluated using yield line theory and punching shear model properly modified for the strengthened RC member. The panels strengthened with sheet type FRP materials failed more often in a ductile mode, indicating that the failure developed after the rebar yielded. Key words concrete bridge deck . yield line theory . punching shear model . strengthening effect
1. Introduction External strengthening has been applied to many deteriorated secondary highway bridge decks after almost 20 years of service in Korea that were originally designed to support less than 30-ton of traffic loads. Strengthening decks to support the heavy J. Sim Department of Civil and Environmental Engineering, Hanyang University, 1271, Sa1-dong, Ansan 425-791, South Korea H. Oh (*) Department of Civil Engineering, Jinju National University, 150 Chilam-dong, Jinju, Kyeongnam 660-758, South Korea e-mail: [email protected] C. Meyer Department of Civil Engineering and Engineering Mechanic, Columbia University, SW 500 West 120th Street, New York, NY 10027, USA
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Appl Compos Mater (2006) 13: 99–114
trucks of over 40-ton used in these days may cause unintended brittle punching shear failures rather than the usual ductile flexural failures that occur after reinforcing bars yield. In over-strengthened deck panels, the reinforcing steel bars do not yield when punching shear failure occurs. In this case, classical Westergaard theory [1] cannot predict whether the deck panel will fail in biaxial bending or by punching shear. Punching shear analysis and yield line theory must be used to analyze a strengthened deck [2–4]. Nowadays, many different types of materials are used to strengthen deteriorated concrete member, such as steel plate or fiber-reinforced polymer plastic [7–16]. Steel plate was most commonly used as a flexural strengthening material [5, 6], until it because less popular, because of corrosion and its heavy weight, in spite of the fact that its material properties are similar to those of reinforcing steel bars. For the last 20 years, research has concentrated on developing new strengthening materials as an alternative to steel plate. Carbon fiber sheets and glass fiber sheets woven in one direction are widely use
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