Project Summary

The Old Blenheim Covered Bridge, located just off of State Route 30, was destroyed by Hurricane Irene floodwaters in August of 2011. The bridge is listed on the National Register of Historic Places and is also a National Historic Landmark. Hoyle Tanner was selected to serve as subconsultant to a regional engineering firm in providing superstructure design services for a replacement covered bridge emulating the original bridge’s design. 

In 1830, the Long Truss was patented by Hopkinton, New Hampshire native Col. Stephen H. Long and was first used by railroads in the United States. It is considered to be the first scientifically designed truss bridge and the first example of an intentionally prestressed bridge. It is unknown how many Long Truss covered bridges were built in the United States; today, only 22 are known to survive. In the past, two lane covered bridges were more common; however, today there are six such bridges remaining in the United States (including the Blenheim Bridge).  

We completed full design and detailing for the 227′-10″ Blenheim Covered Bridge replacement which included 3-D modeling of the bridge and code review for both ASD and LRFD methodologies.  

AWARDS: 2019 Association Bridge Construction and Design – Eastern NY Bridge Project of the Year 

2019 Structural Engineers of New Hampshire Excellence in Structural Engineering 

2019 ACEC-NH Gold Winner – Excellence in Engineering