The project consists of construction of a reinforced concrete tunnel ventilation structure for the Interstate 93 tunnels, with a footprint of 300 feet by 200 feet. The structure has three below grade levels with heights of approximately 30 feet and the roof slab at grade level. The supply structure (50 feet above grade) and exhaust structure (250 feet above grade) are located south and north of the building respectively.
The construction sequence required demolition of the existing electrical substation and switchgear; construction of slurry walls to depths of 100 feet, excavation and associated temporary bracing of slurry walls; construction of the base slab; construction of reinforced concrete walls, columns and supported slabs for sub-grades 3, 2 and 1; construction of roof slab, intake structures and exhaust stacks; installation of all electrical, HVAC, plumbing, and fire protection.
- General Contractor: Walsh Construction Co.
- Contract Value: $72,430,000
- Notice to Proceed: July 11, 1996
- Contract Completion: March 29, 2003
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