CENTRAL ARTERY / THIRD HARBOR TUNNEL - DESIGN SECTION 1A
Boston, Massachusetts
Our staff was responsible for providing all civil engineering work for the Central Artery/Third Harbor Tunnel project, Design Section 1A. For this project, we provided all horizontal and vertical alignment, grading, drainage, utility and pump station design, and agency coordination.
This section of the project, which runs from A Street to D Street, included the cut-and-cover tunnel for Interstate Route 90 as well as the reconstruction of D Street, Summer Street, West Service Road and several other local streets. In addition to the design of this section of the tunnel, we also provided design services for several Massport-owned facilities, including the Temporary Haul Road, the Permanent Haul Road (eastbound and westbound), the temporary World Trade Center ramp, the new viaduct, and the design of Congress Street and B Street.
To allow construction of the cut-and-cover tunnel, all utilities had to be relocated out of a section of Congress and B Streets. The utilities were relocated to a temporary utility bridge between Fargo Street and the western portion of Congress Street. The bridge was later dismantled when the tunnel and utilities were covered in the final phases of construction.
This project involved significant coordination with Massport to provide telecommunications lines for the Seaport Square and World Trade Center redevelopment areas. We worked regularly with Nstar, Verizon, Continental Cablevision of Boston and MCI Worldcom to provide lines in accordance with the Massport specifications. We also coordinated the utilities with the Boston Convention Center Project, being planned for a parcel to the south of the I-90 corridor.
A significant technical problem that we dealt with was the placement of a high fill over the existing utility lines to provide a temporary ramp connection between Congress Street and Summer Street. Because of the fill, we had concerns over the added earth pressure on some of the existing utility lines. We called for a structural pad spanning the affected area to carry the added loads. OSHA and utility company regulations regarding maximum depth of manholes had to be carefully checked at a number of locations.
Client: Massachusetts Turnpike Authority
