New York City's FDR Drive between East 54th and East 63rd streets is a complex, three-level structure comprised of a northbound roadway on the lower level, a southbound viaduct in the middle and a roof structure above. The combination of retaining walls, the East River and the roof structure form extreme geometric constraints.
We conducted a comprehensive inspection and emergency repair program, and designed the rehabilitation of the northbound and southbound roadways, as well as the roof structure. A conventional construction approach would involve lanes closures on both the southbound and northbound roadways. To minimize these effects, we developed an outboard detour roadway alternative to route traffic onto a new structure over the East River, replicating the traffic-carrying capacity of FDR Drive and preserving all entrances and exits. This solution reduced both delays and spill-over of traffic into the local community.
With the outboard detour in place, the northbound structure was rehabilitated with a new 40-foot-deep bulkhead. The detour also allowed for implementation of a more standard southbound roadway viaduct structure, which was grafted onto the existing substructure. We improved the geometry of the southbound roadway by adding acceleration lanes, super elevations, improved line-of-sight distance and positive drainage. A state-of-the-art concrete rehabilitation program was implemented to stabilize and seismically retrofit existing concrete components. We rehabilitated the roof structure with new joints, spalling and crack repairs, new waterproof membrane and enhanced drainage.