According to the Federal Highway Administration (FHWA), over 600,000 bridges are registered in the National Bridge Inventory (NBI). Oversized vehicles, usually crossing over or under a bridge in violation of posted height limits, are among the top causes of bridge failure or collapse. A recent survey of DOTs across the country has shown that the impact damage to bridges because of over-height trucks is indeed a nationwide problem. A frequently used protection measure against over-height vehicles is the installation of laser protection systems to provide advanced warning to such vehicles approaching low clearance bridges / tunnels. However, the risk of serious damages to critical bridges / tunnels remains if the driver doesn’t follow the warning signs. Based on these facts, FHWA recently developed an energy-dissipative system prototype using a combination of a steel box beam with aluminum honeycombs for the protection of bridge girders from over-height impacts. This innovative protection device will be effective in preventing damages to concrete and steel beams, while sustaining moderate to severe damage to itself, depending on the intensity of the impact. This project focuses on the full scale testing, field installation and evaluation of the effectiveness of this prototype against over-height truck impacts

The innovative steel beam/honeycomb protective system is anticipated to dissipate a large portion of the energy from the colliding truck by crushing/deforming the honeycombs. The effectiveness of this device has been investigated recently by large-scale testing in collaboration with the researchers at Hunan University, where over-height impact was simulated through a drop hammer system. With the success of the large-scale testing program, the actual field installation of full scale model is deemed necessary to validate its effectiveness to protect existing bridge structures. In particular, this project aims at the following: • Design of the full-scale testing program and selection of bridge site for the field installation; • Custom construction and installation of the full-scale model of the prototype attaching to the existing facial girder of the selected structure; • Full scale testing and evaluation of the system with actual over-height truck impact on site.

Scope of Work: This project will carry out in two phases which include the following eleven (11) main tasks: Phase I ($680K) 1. Develop an over-height impact program for outdoor full scale testing including site & vehicles selection and logistics. 2. Investigate the protection system extensively through numerical simulations on different impact scenarios. 3. Design an effective installation of the proposed protective system including supporting systems, connections, the protective system and means for easy replacement of damaged components. 4. Design the entire setup for full-scale prototype testing including the girders to be impacted or a system supporting girder to be impacted that can represent the behavior of an actual bridge through numerical simulations. 5. Prepare and publish the Phase I report including outcomes of the tasks carried out in this phase. Phase II ($1M) 6. Conduct full-scale prototype testing to demonstrate the effectiveness of the proposed protective system. 7. Perform parametric studies on the impact performance of the protection devices installed on the prestressed /steel girders. 8. Develop a design method for proportioning the protective system to achieve a specific performance (performance based approach). 9. Develop design examples and templates to illustrate the design of the protective system for different impact scenarios. 10. Develop new design guidelines for fascia girder to resist the impact loads due to oveheight heavy vehicles without protection system. 11. Prepare and publish the final report including findings and outcomes of all the tasks completed in this project. .

The Federal Highway Administration (FHWA) is seeking a minimum of five (5) partner states to commit funds in the amount of $70,000 per year for 3 years from FY 2022 to FY 2024. The total funding amount per partner is $210,000. FHWA will be the lead agency. State commitment will cover travel for an in-person meeting approximately once per year throughout the life of the project. Specific meetings and locations to be determined during the course of the project.