Investigation and Damage Mitigation of Low-lying Coastal Bridges under Hurricane-induced Wind and Wave Actions

沿海地区低洼桥梁上的飓风风、浪涌和海浪引起的荷载还不是很清楚。几座沿海桥梁在飓风伊万和卡特里娜中受损。这项研究的目的是研究风、浪和波浪荷载在桥面上的特征，并制定沿海桥梁的缓解对策。具体活动包括(1)开发一种模拟风、浪和波浪荷载对桥面的影响的实验方法；(2)建立一种数值模拟方法来预测确定的风、浪和浪荷载下的桥梁性能；以及(3)研究有效和经济的减灾对策，以减少飓风对沿海桥梁结构的影响。这项研究将集中在中短跨度低矮的肋桥结构，这些结构容易受到风、浪和浪的作用。缓解策略包括对桥梁桥面进行气动流线化和机械加固桥梁上部结构和下部结构之间的连接，同时考虑上部结构和下部结构之间的平衡性能。如果成功，这项研究将导致更好地定义设计荷载和更好地了解沿海桥梁的性能，并为这些结构的设计提供必要的技术数据，并为飓风环境下沿海桥梁的安全评估提供分析工具和方法。预计这将导致更好的桥梁设计，在飓风引发的极端风环境中减少损害。将为外联活动准备有吸引力的示范和教育工具，并提高公众对飓风结构工程的认识。将开发结合本研究结果的设计工具，供从业者设计更安全、更经济的沿海桥梁结构。该项目还将通过参与项目研究活动来培训研究生。

Hurricane wind, surge, and wave induced loads on low lying bridges in coastal areas are not well understood. Several coastal bridges were damaged in Hurricanes Ivan and Katrina. The objective of this study is to characterize the wind, surge, and wave loads on bridge decks, and to develop mitigation countermeasures for coastal bridges. The specific activities include (1) developing an experimental method to simulate wind, surge, and wave loading effects on bridge decks; (2) establishing a numerical simulation methodology to predict the bridge performance for the defined wind, surge, and wave loads; and (3) investigating effective and economical hazard mitigation countermeasures to reduce the impact of hurricanes on coastal bridge structures. This study will focus on short and medium span low lying costal bridge structures that are vulnerable to wind, surge, and wave actions. The mitigation strategies include both aerodynamic streamlining of bridge decks and mechanical strengthening of the connections between the bridge superstructure and substructure, considering a balanced performance between the superstructure and substructure. If successful, the research will lead to better definition of design load and improved understanding about the performance of coastal bridges, and provide essential technical data for the design of these structures and analytical tools and methodologies for safety assessments of coastal bridges in a hurricane environment. This is expected to lead to better bridge designs with reduced damage during a hurricane induced extreme wind environment. The attractive demonstrations and education tools will be prepared for outreach activities and to increase the public awareness of hurricane structural engineering. The design tools incorporating the results of this research will be developed for practitioners to design safer and more economical coastal bridge structures. The project will also train graduate students through their involvement in the project research activities.