Greenbanks Hollow Covered Bridge, Danville Vermont
- Categories:
- Vermont
- Covered Bridges
- Queenpost Truss
The Greenbanks Hollow covered bridge is the last covered wood bridge to survive in the town of Danville. Herbert Wheaton Congdon states that the bridge was built originally without its roof and was covered later.
The Greenbanks Hollow bridge displays marked architectural similarity to the five covered bridges in the adjoining town of Lyndon. Generally, the bridges have open upper walls, extended eaves, projecting gable ends, and portals framed either with diagonal upper corners or arches, each complemented by Similar forms under the eaves. These characteristics identify the most distinctive regional design among the covered bridges in Vermont.
The covered bridges of Vermont are among its most cherished and symbolic historic resources. About one hundred bridges still stand in the state, the greatest concentration by area of covered bridges in the country.
Bridge Description
The Greenbanks Hollow covered bridge consists of a single-span supported by two flanking timber queenpost trusses. The trusses incorporate iron suspension rods that extend from the upper apexes of the diagonal braces to the bottom chords. A central laminated stringer has been added to the underside of the floor beams for reinforcement; the stringer comprises several shorter timbers tie-bolted together.
The bridge has been additionally reinforced by two steel beams laid on the deck immediately inside the trusses and tie-bolted to the chords. The beams extend 49 feet from the south portal; at their north ends, two concrete-filled corrugated metal pipes have been placed under the bridge as a temporary bent. A concrete retaining wall has been built on the north edge of the brook to support the bent. The original abutments are built of irregular stone laid dry; the north abutment has mostly collapsed.
The Greenbanks Hollow bridge is skewed at the south portal, being almost 73 feet long at floor level on the west side and 74.5 feet on the east side. The gable ends project 4.5 feet beyond the floor at each portal. The bridge is 16.5 feet wide and has a 15-foot roadway. The wood floor consists of planks laid on edge and parallel to the trusses, with other planks over-laid flat and transversely to serve as driving surfaces.
On the exterior, the heavy timbers pegged together to form the trusses (and side walls) of the bridge are sheathed with unpainted flush boards hung vertically. The boards reach only about half the height of the side walls; the upper halves are open, revealing the structural members.
The gable ends are also sheathed with flush boards hung vertically, and display weathered traces of white paint. The portal openings are rectangular except for diagonal upper corners. The sheathing flares outward from the portal openings to the eaves. The medium-pitch gable roof is covered with corrugated metal sheeting. There are extraordinarily wide overhangs at the eaves to protect the exposed trusswork below.
South portal (1973)
