An architectural rendering of the finished bridge
On Aug. 2, 2010, two Office of Research Facilities employees, Tony Chestang and Joe Jackson, were performing routine campus site inspections and discovered structural concerns with the existing “Northeast” bridge servicing North Drive off of Rockville Pike.
Over 30 years, the previously wooden-decked bridge had been replaced with metal decking. Reinforced concrete slab and decorative stone walls had been placed at the outer edges of the bridge.
The two employees discovered that the south girders—supports that raise the bridge off the ground—were damaged. The cantilever used to help support the bridge was sagging and the metal and concrete decking was starting to leak.
Chestang immediately contacted his supervisor, Paul Hawver, and all traffic was stopped from crossing the bridge. ORF senior structural engineer John Pavlides was called in to further study the bridge. Following his initial assessment, a decision was made to block off the south portion of the bridge, allow traffic to use the north portion and begin the procurement process to repair or replace the bridge.
In April 2011, under the direction of ORF’s Marjorie Marcus, NIH hired a firm to conduct a preliminary assessment of the bridge. The study’s result included 6 options for repair or replacement ranging in lifespan, types of materials used and locations for a new bridge. Options included everything from a short-term repair lasting 5 to 8 years, all the way up to long-term replacement lasting at least 50 years. NIH chose the long-term option—a bridge designed to hold for at least 50 years made out of precast concrete and located in the same place as the existing bridge.
By November 2014, the final design was completed by Howard Leroy Shrodes/Paige Industrial Services (HLS-Paige) Joint Venture. The design called for an approximate quarter-acre two-lane concrete bridge, 50 feet long by 30 feet wide, with protective “parapet” retaining walls faced with natural stones on both sides and supported by two concrete abutments at each end. The project also called for replacement of electrical conduit and communication lines, embedding them inside the bridge. Lenin Andrade was named ORF project officer overseeing construction of what became known as the North Bridge Replacement Project.
The contract was awarded to HLS-Paige Joint Venture and construction began in January 2015. Quality control, quality assurance and daily site inspections by the AFG Group have assured that the project adheres to all local, state and federal codes, especially requirements for sediment and erosion control, as the bridge is built over a stream that feeds into Rock Creek and contains marine life and occasional waterfowl. The bridge meets American Association of State Highway Officials design standards, capable of handling up to an 85,000-pound loading capacity and large emergency vehicles.
Initially, the bridge was set to open on Sept. 30. However, construction moved ahead of schedule. The new bridge debuted Aug. 10.