Site work for a transportation facility in Boston, Massachusetts. Completed plans call for site work for a transportation facility.

Provide a new access point to the Red Line northwest of the Charles River that will accommodate equipment, labor, and material delivery into the tunnel more efficiently. The MBTA Red Line subway northwest of the Charles River consists of a below grade tunnel with access for equipment, such as Hi-Rail vehicles, and maintenance only available just east of the Kendall/MIT station, some four miles from Alewife Station at the First Street gate. With the existing tunnel being over 25 ft. below ground surface near Alewife, a tunnel is the most practical means of providing access from grade to the tunnel below for access. Contractor Qualification DCAMM Certificate Required for DCAMM contracts over $150,000, Highway Division contracts over $50,000. SCOPE OF WORK This Project will complete design and construction to create the new access point to the Red Line Tunnel in Cambridge, MA. The Base Technical Concept (“BTC”) consists of a 15-ft wide paved access road, approximately 150 feet in length, followed by a boat section ramp approximately 130- ft long that provides below-grade access to a new tunnel that ties into the existing Red Line tunnel approximately 150-ft from the end of the boat section ramp. The BTC includes constructing the new tunnel structure and boat section ramp within a support of excavation system (SOE). The proposed SOE system includes sheet piling walls, internal bracing, and a working base slab over a jet grout bottom plug. Soil within the excavation area is contaminated and a Final Release Abatement Measure (RAM) needs to be developed that follows the methods described in the Draft RAM plan submitted to the Massachusetts Department of Environmental Protection (MassDEP) in August 2024 or the Public Involvement Plan (PIP) process needs to be reinitiated. Dewatering will also be required as part of the excavation and water needs to be properly discharged. The tunnel and boat section ramp structures are detailed for conventional form and pour concrete methods starting with the base slab and progressing upward to the top of the boat walls and the tunnel roof slab. The final grading and tree planting plan needs to be in accordance with the Order of Conditions issued by the Cambridge Conservation Commission on January 6, 2025, otherwise the process to receive a new Order of Conditions needs to be re-initiated.