Hereford Bridge Project

Hereford Timeplapse Screenshot
  • Transportation
  • Bridging
  • Hereford, MD
  • May 2017

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Jim Porreca - Bridging

Bridging & Structural Shoring Specialist | Pittsburgh Depot

1 (412) 475-6087


The Maryland Department of Transportation State Highway Administration (MDOT SHA) needed to replace the MD 137 (Mt. Carmel Road) Bridge over I-83 (Baltimore-Harrisburg Expressway) in the Hereford community of Baltimore County in May 2017. The 62-year-old bridge was safe, but was rated “structurally deficient” and had outlived its service life. The challenge with this particular project, as with many others, is MDOT SHA needed to keep the road open so that the more than 9,500 vehicles which use Mount Carmel Road over I-83 each day could continue to have access. This required the design and installation of a temporary span that could protect workers and highway users during the project to reconstruct the bridge.

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MDOT SHA chose an innovative approach of using a modular, temporary bridge for motorists to use during construction. The Six M Company, Inc., MDOT SHA’s contractor, worked with Mabey Inc. to develop an engineered solution using the Mabey Universal Bridging System (MU). The heavy-duty modular design of the MU provides a unique combination of strength and versatility, along with excellent fatigue resistance, making it ideally suited for this application. At 206’ long, a 2-span temporary bridge was installed north of the existing bridge and consisted of two lanes designed to carry HL93 highway traffic loads. Traffic was shifted to the temporary bridge upon installation to ensure that all travel lanes were maintained during construction. Mabey also supplied the temporary shoring towers that were used to support the temporary bridge at the mid-span location.

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Using Mabey’s MU temporary bridge reduced the impacts on the environment and nearby residents while allowing minimal disruption to the traffic patterns. The cost to rent the bridge was offset by the ability to keep MD 137 on its original alignment, which reduced the need for additional drainage, material fill and tree removal. Additionally, the temporary bridge allowed crews to work without traffic immediately adjacent to the work area, enhancing safety for workers and drivers. It is projected that this bridge replacement project will be fully complete in summer of 2018.

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