The bridge opened to traffic on August 26, 1929. It was one of the first continuous truss road bridges built in the nation, and exhibited characteristics of both a through truss and deck truss design. The bridge was initially tolled; however, the tolls were removed on September 22, 1987. The bridge was rehabilitated in 1991. Work performed at that time included the replacement of the deck and railings, the repainting of the steel trusses, and the repairing of the bridge piers. In the mid-2000s, the New York State Department of Transportation and the Vermont Agency of Transportation launched the planning process for a project that would result in either the rehabilitation or replacement of the Champlain Bridge. At the time, the projected start date for the project was 2012. However, in 2009, an inspection performed on the bridge as part of the planning process revealed that two of the bridge's support piers were not structurally sound. As a result, the bridge was closed to all traffic on October 16, 2009. NYSDOT Regional Structural Engineer Thomas Hoffman commented that "Under certain conditions we were afraid the bridge could fail abruptly." Prior to the closing, the bridge had already been reduced to one lane for structural steel repairs.
Effects of the closure
The closure of the bridge caused economic hardship for commuters and local businesses as traffic was greatly reduced on both sides of the lake. Two businesses that saw more activity were private ferry services; one about south of the bridge was overwhelmed, while the other expanded its hours of operation. Even with expanded hours, and New York state subsidies, the two private services could not meet demand. The state explored adding a ferry at the bridge location, and the Basin Harbor Club made its tour boat available to ferry pedestrians. Since the lake freezes in winter, an ice-breaker would be required to keep the ferry services running. The Ticonderoga Ferry was forced to suspend service due to icy conditions from December 17 to December 20, 2009. On February 1, 2010, Lake Champlain Transportation started a new ferry service at the site of the demolished bridge, operating with two boats, departing each side of the crossing every 15 minutes, 24 hours a day as a free service subsidized by NYSDOT.
Demolition and replacement
On November 9, 2009, officials in Vermont and New York announced that the bridge was beyond repair and would have to be demolished. Removal of the existing bridge was accomplished by explosive demolition, and was originally scheduled for December 23, 2009. On December 22, officials moved the demolition date to December 28 as a result of the formation of ice on Lake Champlain and cold weather in the area; both factors led to delays in installing the necessary explosives for demolition. The bridge was demolished at 10:03 am on December 28, 2009. The bridge was replaced by a new structure, a Modified Network Tied Archconcept design. Flatiron Constructors of Longmont, Colorado, the U.S. subsidiary of German firm Hochtief AG, won the contract for the new bridge, and groundbreaking took place on June 11, 2010. The replacement bridge opened to traffic on November 7, 2011.