Modjeski and Masters opens new double bascule bridge

Mechanicsburg, Pa. — In a ribbon cutting ceremony held Friday, May, 15, the North Carolina Department of Transportation, along with the bridge design and engineering firm Modjeski and Masters and Archer Western Contractors, officially unveiled the new eastbound span of the Pasquotank River Bridge. Located in the heart of Elizabeth City, N.C., the bridge carries US 158, automotive, bicycle and pedestrian traffic over the Pasquotank River.

The opening of the span culminates over four years of design and construction work on the project. The bridge is part of the North Carolina State Transportation Improvement program that will replace 838 bridges across the state. Designed by Modjeski and Masters in just eight months, demolition on the original structure began in February 2011. The original bridge was built in 1931.

“The most challenging aspects of the design process were balancing loads on an asymmetrical span while reducing the overall weight of the structure,” said Kevin Johns, Director of the Movable Bridge Unit at Modjeski and Masters. “As a bascule span is constantly in motion, it’s important to reduce structural weight where possible. Our team did so by using lightweight concrete in the grid deck and sidewalks. Additionally, dense Styrofoam was used in the design to lighten half of the counterweight section and create precise balance for the bridge. Another noteworthy aspect of the project was our persistent focus on enhancing maintainability by developing a design which provides ease of access to all components that require routine or periodic maintenance.”

The weight of each bascule leaf is approximately 1.1 million pounds. Each counterweight contains around 132,000 pounds of steel ballast and 90 cubic yards of concrete. Each bascule leaf contains around 450,000 pounds of AASHTO M270 Grade 50 structural steel.

The new bridge will stimulate economic integration between neighboring Camden, Pasquotank and Perquimans Counties. It will smooth automotive traffic flow through Elizabeth City, which is considered the heart of the region. It will also make it easier for boat traffic to navigate the Pasquotank River.

“The Elizabeth City project has been very successful from both the owner’s and contractor’s perspective. A lot of that comes from Modjeski and Masters’ quality design plans and timely responsive assistance during construction. The quality of their design plans made a complex job less cumbersome,” said Randy Midgett, the Resident Engineer for the North Carolina Department of Transportation.

Modjeski and Masters is also involved with rehabilitating the westbound span. Construction on its redecking, new electrical system, structural repairs, and the replacement of some of its machinery is expected to finish before the end of the year.