Case Study #1: West Cornwall Bridge, Cornwall-Sharon
West Cornwall's covered bridge has a long history of problems. In 1939 the bridge was posted for a ten-ton limit after a state inspector observed, flood waters in 1955 nearly swept the bridge away. In 1961, a huge ice jam built up around the pier and abutments; only dynamiting the ice saved it from certain destruction. The bridge was raised up about two feet, and a steel orthotropic deck was inserted to carry the traffic independently of the timber truss. The deck consists of two large side beams and a 3/8-inch thick top plate reinforced by 9-inch U-shaped ribs, all welded together.