Development of wave and surge atlas for the design and protection of coastal bridges in South Louisiana.

PDFTech ReportFHWA/LA.528LRTC No. 10-4STSIO No. 30000118CoastsBridgesStorm surgesHurricanesWater wavesWave heightGeographic information systemsBearing capacityLouisianaLouisiana Transportation Research CenterSheppard, D. MaxDompe, Philip E.Gosselin, Mark S.Demir, H\uc3\ubcseyinOcean Engineering Associates, IncorporatedUnited States. Federal Highway AdministrationLouisiana. Dept. of Transportation and DevelopmentUS Transportation CollectionThis report summarizes the work performed by Ocean Engineering Associates, Inc. (OEA), a divisionof INTERA Inc. (OEA/INTERA), for Louisiana Department of Transportation and Development(DOTD) on (1) the development of a Wave and Surge Atlas for coastal Louisiana and (2) thedetermination of the vulnerability of selected DOTD coastal bridges to design storm surge and waveloads. In this study, the bridge is considered to be vulnerable if the surge/wave forces and moments(with the appropriate load factors) exceed the resistive forces and moments created by the dead weightof the superstructure for any of the spans. A Level III storm surge/wave analysis was performed toprovide the design water level and wave parameters needed to compute the loads. This analysis entailed(1) the hindcasting of 50 of the most severe tropical storms and hurricanes that have affected Louisianacoastal waters over the past 160 years, and (2) performing extreme value analyses on water elevationand wave heights throughout the area covered by the model to obtain 100-year design met/oceanconditions. To increase the data set for the extreme value analyses, a select number of the hindcastedstorm paths were shifted to the right and left of the actual path and the modified-path stormshindcasted. This resulted in 124 hindcasts to perform. The results from the extreme value analyses wereused to create a Wave and Surge Atlas. The atlas is presented in a GIS database for ease of access anduse. The information in the GIS database has many applications beyond that of providing theconditions needed for computation of surge/wave loads on the bridge superstructures