Project Summary

The String Bridges are two, 50′ span reinforced concrete rigid frame bridges that were constructed in 1935 and are located in a National Register Historic District. The bridges carry String Bridge—the name of the roadway—over the Squamscott River to Kimball Island which is located in the middle of the river. The bridge carries numerous utilities including buried gas, water and sewer as well as overhead power, cable and phone lines. With the exception of routine paving, minor repairs and installation of a waterproofing membrane in the 1990s, very little work has been completed to the bridges since they were constructed. 

An inspection team from Hoyle Tanner performed a detailed, hands-on inspection of each bridge.  During the inspection, the bridges were found to be generally in fair to good condition with some select areas in poor condition due to accelerated concrete deterioration. 

A complete rehabilitation of both bridges was completed over two construction seasons and included concrete repair, relocation of overhead utilities to underground, the addition of period light fixtures and reconstruction of the roadway. The project was completed through the NHDOT Municipally-Managed State Bridge Aid Program.