Project Highlights:
- Coordination with the U.S.
Coast Guard, fuel terminal
merchants, local marinas, and
harbormasters.
- Four 60foot diameter dolphins
with 120’ sheet piles and
concrete cap.
- Bridge electrical control
systems, five submarine cables
for bridge power, controls and
architectural lighting.
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This MassDOT DesignBuild project consists of a new vertical bridge to replace the existing temporary drawbridge including approach spans from Quincy and Weymouth. The new drawbridge consists of two 250 foot high towers and a 324 foot long vertical lift span,in addition to two 500 foot fixed approach spans, earth ramps and all navigable channel dolphins and fenders. The bridge provides 175 feet of vertical clearance above mean high water when in the open position and 54 feet of vertical clearance in the closed position. The navigable channel was also increased in width from 175 feet to 250 feet.
The bridge operating machinery includes eight 20 foot diameter main counterweight sheaves along with primary and secondary reducers, drive shafts and motors. The bridge
machinery and counterweight system is designed to lift the drawbridge 115 feet. The bridge electrical system is fully redundant with A and B power systems and communications systems and employs relay based logic control with PLC based monitoring. Power and communications are maintained between the towers through the use of 5 submarine cables within the channel. The 324 foot liftspan was floated into position between the towers. The floating operation involved rolling the 3.1 million pound liftspan on to two barges.
Contract value: $268,950,000. |