The Merritt Chapman and Scott Corporation of New York built the $7 million project. First, a trench by had to be dug. Second, the sections had to be locked into position 85 feet underwater. Finally, the last touches, such as tiling the inside, were completed. It is the only underwater vehicle tunnel currently in operation in the state, as the Baytown Tunnel was replaced in 1995 by the Fred Hartman Bridge. The tunnel consists of a single bore, 895 meters in length, with a six-percent roadway grade outward from the center towards each exit. Forced transverse ventilation is potentially provided by three automatic high-speed Westinghouse Sturtevant blower fans located in a tower at the north entrance. These fans are designed to keep the air free from high-levels of carbon monoxide. In the event of electrical failure, a generator can support the electrical needs of the tunnel. Every twelfth light is powered by a generator. The light intensity at the portals is three times brighter than the interior. This prevents temporary blindness when entering the tunnel. Pumps located under the road surface counter accumulation of water by draining it back into the ship channel. Before Hurricane Ike in 2008, the tunnel had never been flooded. The tunnel is one of five vehicular crossings of the Ship Channel. The other four are the Sidney Sherman Bridge, popularly known as the 610 or Ship Channel bridge; the Sam Houston Ship Channel Bridge, formerly the Jesse JonesToll Bridge and popularly known as the Beltway 8 Bridge; the Fred Hartman Bridge connecting La Porte, Texas and Baytown, Texas; and the Lynchburg Ferry. The tunnel is also the only twenty-four-hour operation in Precinct Two. The tunnel was added to the National Register of Historic Places on April 16, 2008.
Specifications
Total Cost: $7,683,915 Total Length: 3,791 Ft. Distance between Portals: 2,936 Ft. Length of Tube Section: 1,500 Ft. Roadway Width: 22 Ft. Headroom : 13 Ft. Headroom : 18 Ft. Internal Diameter of Tubes: 32 Ft. External Diameter of Tubes: 38 Ft. Max. Grade: 6% Max. Dept : 45 Ft. Max. Dept : 68 Ft. Max. Dept : 80 Ft. Dredging: 425,273 cu. yards Excavation: 289,600 cu. yards Tremie Concrete: 11,750 cu. yards Concrete: 34,250 cu. yards Steel in tubes: 2,373 tons Ceramic Tile: 1,061,000 Number of fans: 3 Max Ventilation: 760,000 cfm Complete Air Exchange: 2 minutes
