Fatigue behaviour of shear connectors for steel-precast composite bridge girders

由于1950年代至1970年代的大规模建设，加拿大正进入一个前所未有的基础设施维修和更换义务时期。维修和更换桥梁尤其具有挑战性，因为它们是交通的天然瓶颈。丧失机会成本、延迟交付、浪费燃料、增加空气污染和增加碰撞频率都是由于封闭车道造成的交通拥堵的直接后果。正是由于这些原因，加速桥梁建设（ABC）的好处正在实现，并应进一步利用。为此，由预制混凝土桥面板连接到钢梁的组合模块化桥梁系统越来越受欢迎。这些系统在公路桥梁、救灾结构、绕道桥梁和工作平台中有应用。用于这些系统的剪力连接可以显着影响施工时间，环境成本，结构完整性和桥梁的耐久性。考虑到这一点，需要进行研究，以更好地了解并找到改善这些连接行为的方法。 在这一背景下，该项目的目标是：1）进行梁疲劳试验直到失效，以研究两种连接类型在循环荷载下的行为，2）进行有限元（FE）和可靠性分析，以研究不同配置的钢-混凝土组合桥梁中剪力连接件失效的后果，根据研究结果，针对不同的连接件类型、位置和主梁配置，提出改进的设计方法。 拟议的方法将包括实验室测试和分析研究相结合。总共18根组合梁将使用以下连接器类型之一进行组装：1）灌浆袋中的剪力螺柱连接器，2）高强度贯穿螺栓剪力连接器，或3）高强度螺纹插入剪力连接器。这项工作的主要成果将是一个重要的一步，在几个钢预制复合抗剪连接系统的发展，加快桥梁建设。

As a consequence of mass construction between the 1950s and 1970s, Canada is entering into a period of unprecedented infrastructure maintenance and replacement obligations. Maintaining and replacing bridges is especially challenging because they are natural bottlenecks for traffic. Lost opportunity costs, late deliveries, wasted fuel, increased air pollution, and increased collision frequency are all direct consequences of traffic congestion due to closed lanes. It is for these reasons that the benefits of Accelerated Bridge Construction (ABC) are being realized and should be further leveraged. Towards this end, composite modular bridge systems consisting of precast concrete deck panels connected to steel girders are becoming increasingly popular. These systems have applications in highway bridges, disaster relief structures, detour bridges, and work platforms. The shear connections employed for these systems can significantly impact construction time, environmental cost, structural integrity, and durability of the bridge. With this in mind, research is needed to better understand and find ways to improve the behaviour of these connections. Against this background, the objectives of this project are: 1) to perform beam fatigue tests until failure to study the behaviour of two connection types under cyclic loading, 2) to perform finite element (FE) and reliability analyses to investigate the consequence of failure of shear connectors in steel-concrete composite bridges with various configurations, and 3) to propose improved design procedures based on the results of this research, for different connector types, locations, and girder configurations. The proposed methodology will include a combination of laboratory tests and analytical studies. A total of 18 composite beams will be assembled with one of the following connector types: 1) shear stud connectors in grouted pockets, 2) high strength through-bolt shear connectors, or 3) high strength threaded insert shear connectors. The main outcome of this work will be a significant step forward in the development of several steel-precast composite shear connection systems for accelerated bridge construction.