The objectives of this study are to
1. Conduct a second, large-scale physical model study of wave loads on a highway bridge superstructure under realistic wave conditions and bridge geometries,
2. Determine methods for the repair and retrofit of existing bridges, and
3. Evaluate the capability of selected advanced numerical models for wave loads on bridges.
This project will directly address the repair and retrofit issues for existing bridges that can better resist or even reduce wave loads, such as vents to reduce buoyancy effects, tie downs, and new connections between the girder and bent caps.
This one-year project is a continuation of the 2006-07 study funded under OTREC. The 2007-08 project will conduct a second, large-scale hydraulic model test of wave forces on a highway bridge superstructure cross-section, leveraging the experimental setup developed for the first project. In addition to the physical modeling, a state-of-the-art numerical model for waves-structure interaction will be developed under this project. Two graduate students will be trained in the area of wave-structure interaction, and two undergraduate students will be involved in this research. Project results will be disseminated through peer-reviewed publications and national meetings.
The hydraulic model study will be conducted in the Large Wave Flume at the O.H. Hinsdale Wave Research Laboratory at Oregon State University, the largest facility of its kind in North America, in conjunction with the Kiewit Center for Infrastructure and Transportation. The model will be scaled 1:5 for length and 1:2.24 for time using Froude similitude. The bridge specimen will be the same as that used for the 2006-07 project, based on a realistic cross-section, and a specially designed load cell will provide horizontal and vertical forces and moments. The connections between the specimen and load cell will be a new design to dampen the lateral energy transferred to reduce the maximum moments at the mudline. Direct comparisons with the 2007 tests will verify (or refute) the efficacy of new retrofit measures.
The prediction capability of selected coupled fluid-structure interaction numerical models will be calibrated again the large-scale experimental results. These models include LS-DYNA, an advanced finite-element based nonlinear fluid and structural mechanics code containing state-of-the-art impact capability; and a fully nonlinear boundary-element based hydrodynamic code with wave impact capabilities. These two models are being examined and improved for future hurricane loads on bridge structure prediction and design development use.
This project advances technologies leading to safer design and repair of bridges subjected to wave loadings. The project will provide guidance on retrofit methods for existing methods and the efficacy of numerical models in predicting wave loads. The resulting methodology may serve as a foundation for extensions to other hazard assessment applications including tsunami effects.