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

飓风、风暴潮和波浪对沿海地区低洼桥梁的影响还不是很清楚。几座沿海桥梁在伊万和卡特里娜飓风中受损。本研究的目的是表征桥梁甲板上的风、浪涌和波浪荷载，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、浪涌和波浪荷载对桥面影响的实验方法；(2)建立了一种数值模拟方法来预测桥梁在风荷载、浪涌荷载和波浪荷载下的性能；(3)研究经济有效的减灾对策，减少飓风对沿海桥梁结构的影响。本研究将重点研究易受风、浪涌和波浪作用影响的短跨和中跨低洼沿海桥梁结构。缓解策略包括桥面的气动流线型和桥梁上部结构与下部结构之间连接的机械强化，同时考虑上部结构与下部结构之间的平衡性能。如果成功，这项研究将有助于更好地定义设计荷载，提高对沿海桥梁性能的理解，并为这些结构的设计提供必要的技术数据，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，减少在飓风引起的极端风环境中的损害。将为外展活动和提高公众对飓风结构工程的认识准备有吸引力的示范和教育工具。结合本研究结果的设计工具将为从业者设计更安全、更经济的沿海桥梁结构而开发。该项目还将通过参与项目研究活动来培养研究生。

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.