Chestnut Street bridge on track for May reopening

posted on 3/22/2023

The Chestnut Street bridge work remains on schedule to reopen to vehicular and pedestrian traffic by May 19, 2023. The project remains on budget.

The contractor has completed the needed repairs to the Chestnut Street bridge deck. Approximately 5% of the deck area was delaminated (failing) and needed restoration. The repairs required partial-depth repairs consisting of removing and replacing about half of the deck’s concrete thickness. The installation of the membrane and pavement are weather-dependent activities; therefore, the project will not be completed until warmer temperatures become more consistent.

The west sidewalk has been completely reconstructed with the existing granite curb reset, new concrete, and resetting the existing bridge railing. Nine utility conduits within the west sidewalk posed a challenge during the demolition of the west sidewalk. The utilities were determined to be fragile and not feasible to relocate; therefore, the contractor altered their means and methods to reconstruct the west sidewalk, which has been more time-consuming. The added work did not alter the project schedule.

The east sidewalk remains under construction, with the existing granite curb reset and reinforcing steel installed. There are also utility conduits within this sidewalk, which the utility companies have upgraded during the construction. The east sidewalk reconstruction is anticipated to be completed in the next few weeks.

The New Hampshire Department of Transportation’s “Recommended Investment Strategy” contains recommended schedules for routine maintenance activities of various bridge structure types. Routine maintenance activities are timely investments made at prescribed intervals to maximize service life while minimizing the life-cycle costs of the bridges. For girder-type bridges, like the Chestnut Street Bridge, NHDOT recommends the following to occur every 20 years: patching the concrete deck and substructure, replacing membrane and expansion joints, and repaving. At 60 years, the NHDOT recommends a complete deck replacement. Until the current work, the Chestnut Street Bridge, constructed in 1973, has only the roadway expansion joints at each end of the deck replaced, which occurred in 2016.

The current project incorporates the recommendations from the December 2018 evaluation completed by the city’s engineering design consultant, which consists of replacing the membrane and pavement, concrete deck repairs, and reconstruction of both sidewalks.

For more information, contact Community Services at 603-516-6450.