The existing literature is not adequate for confidence in wave loads on bridge decks for the design of highways. While several of the existing methods likely provide adequate estimates of loads for some situations and may prove to be adequately adaptable to all situations for the highway bridge deck problem, at this time, there is too much uncertainty and too many untested situations for confidence in design. This uncertainty is primarily a result of a lack of model tests with highway bridge deck geometries with modern wave generation capabilities. Estimates from the existing literature do indicate that the wave loads can be sufficient to cause the recently observed bridge and structure damage.

Some of the methods from the coastal and ocean engineering literature can be adapted at this time to provide preliminary estimates of wave loads on highway bridge decks for the case of deck elevations at or above the storm surge elevation. Specifically, the methods of Wang (1970), French (1970), McConnell, et al. (2004), Overbeek and Klabbers (2001), Bea, et al. (1999), and Kaplan (1995) can be used for preliminary estimates of wave loads on bridge decks near or above the surge level with some significant assumptions, extensions and adaptations. However, the unique cross-sectional geometry of U.S. highway bridge decks adds another level of uncertainty to such adaptations. The only testing of highway bridge cross-sections in the existing literature, Denson (1978, 1980) may have had some unrealistic wave kinematics due to wave generation limitations and laboratory-prototype scaling issues.

The new method for estimating wave loads developed in this study is recommended as interim guidance for highway bridges. It is an adaptation of McConnell, et al. (2004).