The Public Works and Building Committee on July 17 heard a detailed engineering study on the Rochester Neck Road bridge that concluded the structure is nearing critical condition and that full replacement is the likely long-term solution.

The study’s lead presenter, Aaron Lachance, a senior structural engineer and vice president with Hoyle Tanner, told the committee the bridge—built in 1979 and last rehabilitated in 1999—is in “fair” condition but is “very close to being red listed.” He said inspectors rated the bridge overall 5 out of 9, with the superstructure rated a 5 and the substructure a 6, and noted the five steel girders were repurposed from an earlier project and may be older than the bridge itself.

The study matters because the bridge carries about 1,062 vehicles per day, roughly 13 percent of which are trucks, and serves regional traffic between Rochester and neighboring communities including Dover, Barrington and Madbury.

Engineers described the work done for the study: hands-on bridge inspection, geotechnical borings, traffic counts, origin–destination analysis, environmental desktop checks and preliminary hydraulics review. Key findings included: the bedrock sits about 102 feet below ground; soils near the abutments are soft and subject to settlement; the bridge is adjacent to FEMA flood Zones A and AE, and more detailed hydraulic analysis is needed; and concrete jersey barriers have been installed as an interim safety measure because the existing rail is in poor condition.

Lachance gave estimated costs for options under study: a targeted rehabilitation (superstructure replacement and deck work) could be in the neighborhood of $850,000 and might provide 25 to 50 years of service but carries risk because of the existing abutments; a full replacement with new abutments and superstructure was estimated at about $2.5 million and would meet current New Hampshire DOT design requirements with a design life of 75-plus years. Peter (city staff) told the committee $2,700,000 was programmed in the city’s FY26 budget to advance design and work.

Traffic and emergency-response impacts were a major focus. Engineers used 72 hours of video counts and GPS-based origin–destination data to show that roughly two-thirds of users are pass-through or commuter traffic. The study estimated that permanent closure or removal of the bridge would lengthen some trips by up to 13 minutes and 7.5 miles in an extreme end-to-end detour scenario, and that response times for some emergency units could increase (for example, Rochester fire responses to locations south of the bridge could increase from about 5 to 9 minutes in the scenarios presented).

On the question of whether a new span could be built adjacent to the existing one, Lachance said site constraints—an in-place pump station on one bank and tight river geometry on the other—make a side-by-side build difficult without major permanent impacts.

Committee members asked about how long the bridge might remain serviceable. Lachance said it is hard to predict precisely, because predictable corrosion could be accelerated by an unpredictable storm event that undermines the sheet-pile abutments; he gave a rough range of more than five years but less than 20 years.

The committee discussed construction phasing and disruption. Lachance said a one-year construction duration is feasible if the bridge can be closed to traffic for the work; maintaining a single alternating lane would likely extend the project into two seasons. Stakeholders contacted for the study included Waste Management, Brock Industries, Dover public works, and emergency services; most told staff they opposed permanent closure but could manage a temporary closure for construction.

Committee direction and next steps: members provided consensus direction to continue the engineering study, complete stakeholder engagement and refine a preferred alternative; staff and Hoyle Tanner aim to deliver a final engineering study in late September for committee review.

A full list of study materials, contact information for the consultants and a request for photographs or historic flood information from the public were requested by staff as part of the next-phase work.

Ending: The committee closed the presentation with agreement to proceed with the study and further design work; no formal ordinance or funding vote occurred at the meeting.