The 80-year-old Crown Point Bridge linking New York and Vermont over Lake Champlain crashed into the lake yesterday, as controlled explosions brought down the first U.S. long-span continuous truss bridge for highway traffic ever built. Today, we mourn its loss.
The decades old bridge was closed Oct. 16, when engineers deemed it was unsafe because of severe erosion in its concrete piers.
The implosion was the start of a nearly two-year project to replace the bridge, which stood about 100 miles north of Albany. The demolition crew spent more than a week placing 800 pounds of explosives packed into more than 500 charges that brought the bridge down in sections. Another crew was to begin removing the tons of bridge debris from the channel, a task that's expected to be completed by the spring when construction of the new span is set to begin.
The new bridge is expected to open in the summer of 2011.
The bridge that came down yesterday was opened on Aug. 26, 1929, with a ceremony attended by then-Gov. Franklin D. Roosevelt, the Lake Champlain Bridge was the nation's first long-span continuous truss bridge for highway traffic, and its steel girder arch design was used on numerous other spans.
A continuous truss bridge is a truss bridge extending without hinges or joints across three or more supports. A continuous truss bridge may use less material than a series of simple trusses because a continuous truss distributes live loads across all the spans; in a series of simple trusses, each truss must be capable of supporting the entire load. The main span length of the Lake Champlain Bridge was a mere 450 feet — nowhere near the longest. But it didn't need to be — it was the first.
Photo Credit: Mike Groll