The US 50 span over the Severn River Bridge in Annapolis, MD is 2,856 linear feet long and nearly 100 feet high, serving up to 125,000 drivers during peak Friday afternoons in the summer. Innovation was the key to adding a fourth traffic lane to this critical route connecting central Maryland with the Chesapeake Bay Bridges and the Eastern Shore.
The “Innovative Design and Construction” bridge span project by Maryland State Highway Administration (MDSHA) was contracted to Joseph B. Fay to be renovated and joined. J.B. Fay subcontracted Smith-Midland Corporation to manufacture and deliver the precast median barrier to serve as both permanent and temporary Maintenance of Traffic barrier. The project schedule was aggressive and finishing the work on time was imperative, and the upgrade had to be integrated without making an already tough traffic situation worse.
The U.S. 50/Severn River Bridge Median Barrier Replacement and Lane Reconfiguration was named an Engineering & News Record (ENR) Best Highway/Bridges Project and was a Project of the Year Finalist. ENR’s judges were impressed with what one calls the “really complex” challenge of carrying out the expansion in the middle of a busy highway. One judge noted that Roads & Bridges listed the project as one of the Top 10 bridge projects. They also observed that the combined construction team earned the maximum incentive by finishing the project 38 days ahead of schedule and within budget. Maryland DOT also earned national recognition for the project in the 2019 America's Transportation awards competition, being recognized for its exceptional design with the Operations Excellence Award.
In total, Smith-Midland produced 1,250 tons of concrete for the approach and median barriers. Production lasted approximately 15 weeks at the Midland, VA plant facility. In order to maintain the aggressive schedule, SMC worked six days a week to complete the project.
During fabrication, Fay approached SMC about designing and manufacturing the permanent approach barrier with a large footer poured monolithically, which had originally been designed as cast-in-place. Fay and SMC worked closely together to come up with an approved design. Fay received deliveries on their expedited incentive schedule and MDSHA was extremely satisfied with the end result.
Lean construction practices and planning tools were critical for scheduling and coordinating activities of multiple shifts throughout the construction phase. While the project’s objective was to provide smoother traffic flow, the original plan to use cast-in-place sections for the permanent median barrier complicated the ability to regularly shift lanes during construction. Instead, the project team altered the design to incorporate precast barriers with footing sections that could double as movable traffic-maintenance barriers during nighttime lane closures.
The precast sections’ design was further enhanced to match expansion joint locations and the bridge’s gradually arching profile. This approach allowed the project team to use the same precast forms for barriers on the bridge and the approaches.
Despite working near live traffic, working over water and performing major work during nighttime hours, the project team says it had “no major safety incidents” and zero lost-time accidents. The project had a 2.40 OSHA Recordable Incident Rate during more than 83,300 worker-hours performed.