In late 2014, a CBS News 60 Minutes report, “Falling Apart: America’s Neglected Infrastructure,” found that 70,000 bridges in America—that’s one out of every nine— are considered to be structurally deficient, meaning they need to be replaced or repaired as soon as possible. Today, little has changed in our country’s over 600,000 bridges. Many of these local structures are out of service waiting for repair funding, while others have been fixed with a “band aid” approach or remain untouched mostly due to the escalating cost of transportation projects.
Like many states, Rhode Island continues to make its way through a backlog of transportation projects in order of the most pressing. In late 2015, two interstate highway bridges (East Shore Expressway bridge #475 and McCormick Quarry bridge #476) were at a major failing point and replacement was paramount. The Rhode Island Department of Transportation (RIDOT) decided to use a new innovative bridge design—Geosynthetic Reinforced Soil-Integrated Bridge System, better known as GRS-IBS—to replace the failing bridge abutments. This new method was recently promoted by the Federal Highway Administration (FHWA) and would be the first of its kind in Rhode Island, making it a high-profile project for the state.
GRS-IBS requires installing segmental retaining wall (SRW) blocks with layers of specified aggregates and geosynthetic reinforcement to build the bridge abutment retaining walls, eliminating the need for construction of bridge piles. The design and specifications may vary state-to-state but are strictly adhered to. The GRS-IBS system is proving to outperform traditional single-span bridges throughout the U.S. In addition, using the GRS-IBS system not only significantly reduces all construction costs relative to a traditional bridge replacement, but minimizes the impact on daily traffic, the number of detours and total construction time. In short, this technology represented huge cost savings and multiple benefits to the entire state of Rhode Island.
This RIDOT project was built underneath the overpasses without detouring traffic the entire time of construction for both bridges. The only inconvenience to the general public was the actual transition time from a Friday morning to the following Monday. In a time span of merely 80 hours, the roadways were closed, the old bridge supports underneath were demolished, and the new bridge structures were lifted into place and opened for traffic. A traditional bridge replacement project would have required that the interstate roadways be closed with detours for a month or longer.
This Rhode Island GRS-IBS project is estimated to be one of the largest of its kind east of the Mississippi River. “While Anchor Wall Systems has had success in designing multiple GRS-IBS structures around the country, this was the first project built on a major thoroughfare,” said Jon Huyck, PE with Anchor Wall Engineering, LLC (AWE), who provided design support for the project.
Going forward, Belgard® Commercial and Oldcastle’s Anchor Wall Systems® plan to partner with more state transportation departments looking to save money, time and labor, and still deliver a high-quality product that meets all specifications. “The Rhode Island project was an achievement, but we also learned quite a bit that can be applied to improve future projects,” stated Huyck. “As a partner, we can be a significant resource during planning and design on projects where DOTs plan to implement GRSIBS technology.” Belgard Commercial possesses the technical resources to support this type of DOT project and maintains world-class manufacturing facilities throughout the country.