New Hampshire Route 111 Highway Reconstruction & Bypass Design
NH Route 111, Windham and Salem, NH | NHDOT
This project involved the design of 3.2 miles of roadway east of Exit 3 on Interstate 93; 0.6 miles of widening of the existing roadway; and 2.6 miles of new roadway bypassing existing congested areas. Additionally, the design effort included one mile of reconstruction and widening of Route 28 and 2 miles of widening and modifications to side roads. The project included the design of three bridges; noise walls; and two culverts, one for pedestrians and one for wildlife. Also included were two wetland mitigation sites and two vernal pool mitigation sites. Wildlife crossings were incorporated into the project design for amphibians and reptiles. The project has six signalized intersections, five of which are interconnected. Water quality measures including nine detention basins, and extensive other drainage and erosion control measures were also addressed. Complex maintenance and protection of traffic plans were developed for the project during the four construction contracts.
One of the three bridges included the design of a 176-meter curved, haunched steel plate girder bridge over the Flatrock Brook wetland wildlife area. This structure is 26 meters in width and carries four lanes of traffic with provisions for adding two more lanes. Its abutments and piers are cast-in-place concrete and are over 15 meters in height. Foundation types are spread-footings on rock, supported by steel H-pile. Due to the wetland area, a suspended closed-drainage system was incorporated into the design. This four-span bridge also utilized High Performance Steel Hybrid girders. MJ also prepared a study of live load deflection factors and their effect on potential cost savings by utilizing High Performance Steel.