Development of Wave and Surge Atlas for the Design and Protection of Coastal Bridges in South Louisiana. Tech Summary.

摘要

The failures of highway bridges on the Gulf Coast seen in the aftermath of Hurricane Katrina in 2005 were unprecedented. In the past four decades, wind waves accompanied by high surges from hurricanes have damaged a number of coastal bridges along the north coast of the Gulf of Mexico. Hurricane Camille in 1969 caused damage to bridges across Bay St. Louis and Biloxi Bay in Mississippi. Katrina damaged the same bridges rebuilt after Camille. In 1979, Hurricane Frederic destroyed the bridge connecting the mainland to Dauphin Island, a barrier island near the entrance of Mobile Bay, Alabama. In the 2004 hurricane season, Hurricane Ivan destroyed the bridge on I-10 over Escambia Bay in Florida. There are a large number of coastal bridges in South Louisiana. This study addresses several aspects of evaluation of these bridges including: how many bridges are vulnerable to the impact of hurricanes; determination of the design wave and surge conditions at those bridge locations; and calculation of the wave forces on the bridge superstructures. The storm surge elevation, wave height, and wave period are the three most important meteorological and oceanographic (met/ocean) parameters needed to calculate wave forces according to AASHTO’s Guide Specifi cation for Bridges Vulnerable to Coastal Storms. This information is currently not available for South Louisiana’s coastal waters. To address these concerns, LTRC funded this project to develop the design surge elevations and wave heights for South Louisiana, and present the data in a Geographical Information