New York State has been studying all different types of replacement alternatives for the I-81 viaduct. Many of the alternatives were evaluated during the scoping portion of the process and were examined to see what would best solve the I-81 replacement criteria. Those alternatives were then presented to the public through the scoping document and to receive input. After that the alternatives were screened based on four criteria; purpose and need, property needs, constructability and cost. At the conclusion of that analysis there were four remaining alternatives that were further studied through the DEIS process. The alternatives that were studied are; no build, community grid, viaduct replacement and tunnel. The tunnel option was rejected as a viable option. The DEIS examined the no build, viaduct replacement and community grid alternatives. More on those alternatives can be found here.
The Orange tunnel concept would involve the demolition of the existing viaduct between the NYS&W Railway bridge and the I-81/I-690 interchange and construction of tunnel, carrying two lanes in each direction, from approximately 400 feet south of MLK, Jr. East to approximately James Street. The alignment would be about 1.7 miles long (consisting of a 1.4-mile-long tunnel and .3 miles of depressed roadway segments). The main line of the Orange tunnel would be constructed primarily with a tunnel-boring machine (TBM) in bedrock (generally about 40 to 100 feet from the surface to the top of the tunnel, and from 85 to 145 feet from the surface to the bottom of the tunnel). However, the highway would be depressed as it travels to and from the tunnel portals and connections, and the approaches would involve cut and cover and sequential excavation methods of construction.
I-690, including the I-81/I-690 interchange, would be reconstructed from Leavenworth Avenue to Lodi Street. Both fully directional (with all possible connections) and partial I-81/I-690 interchanges (with five of the eight possible connections) were considered. Under the full interchange concept, the Orange tunnel would carry I-81; under the partial interchange option, existing I-81 would be de-designated as an interstate, and existing I-481 would be re-designated as the new I-81. Almond Street would be reconstructed between Van Buren Street and Burnet Avenue, carrying three lanes and turning lanes as needed in each direction.
The Orange tunnel concept would require the acquisition of 17 buildings. Construction would be anticipated to take approximately 11 years and cost $4.9 billion.