A flood event, resulting from Tropical Storm Irene, severely scoured and settled the east abutment causing uneven settlement of the truss end bearings and racking and distortion of the bridge superstructure. Several of the main timber elements of the bridge were broken. The 93-foot-long, single-span bridge uses Howe truss framing and had a cantilevered sidewalk. The damaged bridge was closed to all traffic.
The Town of Greenfield contracted with DuBois & King of Bedford and Laconia, New Hampshire, an engineering firm with a specialty in covered bridges, to oversee emergency repairs to the bridge and to complete the rehabilitation design. Managing the project is Robert H. Durfee, P.E., a nationally recognized covered bridge expert and Vice President for the engineering firm.
The first task after the flood was to jack up and stabilize the bridge on the existing abutments to prevent further damage and to save it from another flood while the rehabilitation design work proceeded. Repairs were designed for the roof framing, upper and lower lateral bracing, timber trusses, board siding, and bearings. Both abutments are to be removed and replaced with concrete abutments and wing walls. The east abutment will be raised 2 feet to enable greater capacity of the bridge to pass future floodwaters without damage.
Before construction, workers temporarily moved the bridge to the east bank, for replacement of the abutments and to allow greater access to the bridge for repairs. The time-lapse video represents the 4-hour removal of the Green River Covered Bridge. Construction will proceed throughout the summer and the rehabilitated bridge is scheduled to reopen in the fall of 2014.
