Perquimans River Bridge

This design-build project focused on replacing the historic swing span bridge over the Perquimans River, along with the approach structure and roadways. The project began near the Newby Street intersection, crossing the Perquimans River with a new horizontal alignment offset 110 feet east of the existing bridge. This alignment shift minimized impacts to historic homes and allowed for a higher swing span vertical clearance. The bridge spans a causeway, avoiding the reuse of poor soils and eliminating tidal flooding-related closures. The project area is classified as an urban collector, with design speeds ranging from 30 mph to 50 mph.

H&H was responsible for the full design of the new swing span, including structural, mechanical, electrical, architectural, and geotechnical engineering. The new span mirrors the original in appearance to maintain the historical context of the Town of Hertford. It features improved roadway geometrics, load-carrying capacity, and modern operating systems to reduce maintenance. The movable bridge consists of a Warren through truss with a concrete deck, providing two 60-foot navigation channels and a vertical clearance improvement from 7 feet to 12 feet.

The bridge’s substructure includes deep concrete pile foundations protected by a Fiber Reinforced Polymer fender system. The swing span rotates on a pivot bearing, powered by twin electric machinery. Remote operation is possible from a control house 70 miles away. The tender house, designed with strict aesthetic requirements, blends with the local architectural context. Geotechnical analysis for the piers used FB-Multipier and LPile software, and precast concrete piles were chosen for their cost-effectiveness and driveability. Quality control checks ensured compliance with NCDOT standards.