Anchor Construction, ’Zipper Machine’ Star on Bridge Project
The project addresses a daunting task — how can the Maryland State Highway Administration maintain lane capacity to accommodate the highly directional traffic?
📅 Tue August 25, 2015 - Northeast Edition
The project includes widening the westbound direction of the bridge. SHA will replace the bridge deck and supporting steel beams and widen the shoulders on the structure. The result will be 4 ft. (1.2 m) lanes with 10-ft. (3 m) shoulders with bike lanes.
As a part of the Maryland State Highway Administration’s (SHA) ongoing statewide bridge system preservation program, the MD 140 Bridge over Liberty Reservoir/North Branch of the Patapsco River on the Baltimore/Carroll County line is currently undergoing a restoration.
The full estimated cost is $7.3 million. The project started in the late fall of 2013, and should continue and be completed in the spring of 2016, weather permitting. Excess rain has been a factor of late.
The prime contractor is Anchor Construction Corporation of Washington, D.C. The project manager is Mark Allen, and the lead designer is Dan Beck. The prime contractor manager is Joe McElwee.
The bridge reportedly has an average daily traffic volume of 42,000 vehicles per day. Charlie Gischlar, SHA public information officer, noted that MD 140 is highly directional with regard to traffic.
“Citizens who reside in Carroll County travel to major employment regions in Baltimore City and county and travel eastbound in the morning,” he explained. “These same motorists travel back home [westbound] in the afternoon. This presented traffic engineers with a daunting task — how can SHA maintain lane capacity to accommodate the highly directional traffic? Here is the answer — SHA has enlisted the use of moveable traffic barrier to accommodate maximum traffic capacity in the demanded direction [eastbound in the morning and westbound in the afternoon]. The ’Zipper Machine’ is unique in that at approximately 12 noon, it moves the barrier from providing two lanes for eastbound morning traffic to providing westbound afternoon traffic with two travel lanes.”
Gischlar noted that the bridge was constructed in 1946 and was showing signs of age and deterioration. Rehabilitation was necessary to provide an extra 30 to 50 years of service life.
“This was a structurally deficient [SD] bridge, and will be removed from the SD list as soon as construction is completed,” he said.
The project also includes widening the westbound direction of the bridge. SHA will replace the bridge deck and supporting steel beams and widen the shoulders on the structure. The result will be 4-ft. (1.2 m) lanes with 10-ft. (3 m) shoulders with bike lanes.
Some equipment being used to construct the project includes dump trucks, graders, cranes and the moveable barrier machine.
Subcontractors include Traffic Systems Inc. of Harmans, Gray and Sons Inc. of Timonium, and DRM Associates Inc. of Manchester.
Traffic will be maintained during construction, with drivers being shifted during the different phases of the project.
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