A Novel Lightweight Composite Deck System for Long-span Bridges
Xudong SHAO Professor Hunan University Changsha, Hunan, CHINA shaoxd@hnu.edu.cn
Lu DENG Professor Hunan University Changsha, Hunan, CHINA denglu@hnu.edu.cn
Anil AGRAWAL Professor City College of New York New York, USA agrawal@ccny.cuny.edu
Xudong Shao, born in 1961, received his Ph.D. degree in Bridge Engineering from Hunan University. He is a professor in Civil Engineering at Hunan University. His main area of research is related to large-span and new type of bridge structures.
Lu Deng, born in 1984, received his Ph.D. Degree in Civil Engineering from Louisiana State University. He is a professor at Hunan University. His main area of research is related to bridge-vehicle vibration and vehicle loads.
Anil Agrawal, born in1965, received his Ph.D. Degree in Civil Engineering from University of California, Irvine. He is a professor at the City College of New York. His main area of research is related tohazard mitigation of bridges.
Summary Conventional orthotropic steel decks are susceptible to fatigue damage under cyclic heavy vehicle loads. In the past, a number of countermeasures have been proposed to deal with this problem, but none proved to be very effective. To address this problem, a new lightweight composite deck system was proposed. This composite deck system consists of a thin, compactly reinforced, ultra-high performance concrete layer on top of the steel deck. The stiffness of the bridge deck is increased significantly with this composite deck system. Consequently, stress levels at fatigue crackprone details are reduced significantly. The proposed deck system has shown excellent static and fatigue performance, and great potential for application in long-span bridges. The relevant studies and results are presented in this paper. Keywords: orthotropic steel deck; ultra-high performance concrete; lightweight composite deck; experimental test; application.
1.
Introduction
Orthotropic steel decks (OSDs) have been used commonly in long-span bridges to reduce the self42
Volume 47 │ Number 1 │ March 2017
weight, and therefore improve the spanning ability of these bridges. The OSDs are usually covered with a 2 to 3-inch-thick asphalt wearing course. Under cyclic heavy traffic loads, these steel decks are susceptible to fatigue cracks, while asphalt overlays also suffer from cracking and shoving problems, which compromise the serviceability and durability of the bridge deck. To address these problems, a number of countermeasures have been proposed in the past, including increasing the thickness of deck plates, refining the configuration of fatigue-prone details, enhancing the welding quality, etc. However, none of these approaches have proved to be very effective, since none of them provide much benefit for increasing the stiffness of the deck plate. Recently, Buitelaar et al. [1], Murakoshi et al. [2], and Dieng et al. [3] have proposed to use a reinforced high performance concrete (RHPC), a steel-fiber-reinforced concrete (SFRC) overlay and a fiber-reinforced UHPC (UHPFRC) layer, respectively, to strengthen the stiffness of the steel deck. However, these attempts did not achieve satisfactory results. Cracks developed in the RHPC and SFRC, while sliding occurred between the steel deck and UHPFRC layer. The reason was either because the concrete did not have sufficient cracking strength or the concrete The Bridge and Structural Engineer