The Modified Network Tied Arch Bridge is a steel structure that more than meets all the design criteria for the Lake Champlain project.
Less than one month after its demolition New York and Vermont officials — and the public — have selected a design for the new Lake Champlain Bridge.
In January, New York State Gov. David Paterson and Vermont Gov. Jim Douglas announced the Modified Network Tied Arch Bridge concept had been chosen for the new bridge. The public’s preference was one of several factors considered. It also played a significant role in the recommendation to proceed with the unique arch structure option.
“The selection of a design concept for the Lake Champlain Bridge replacement is a major step in restoring this critical connection between New York and Vermont,” said Paterson. “New York and Vermont’s transportation agencies identified the Modified Network Tied Arch Bridge as the overwhelming favorite of the people who live near and depend on this vital link. The next phase of design work will begin immediately as we continue our efforts to restore this important transportation connection.”
Douglas said, “Both the public and our bridge engineers agree the Modified Tied Arch is an outstanding and appropriate design to replace the historic Lake Champlain Bridge. The new bridge will fit easily into the historic surroundings and be a source of pride for residents of both states for years to come.”
The Modified Network Tied Arch Bridge is a steel structure that more than meets all the design criteria for the Lake Champlain project. It has a basket handle arch with a network cable arrangement and internally redundant box tie girders supporting a composite precast deck system. The design is visually pleasing, complementing the environment and protecting the area’s historic nature. The bridge design has an expected lifespan of at least 75 years.
Preliminary plans for the new bridge were released to nearly 70 contractors on Feb. 1. Bid was released on Feb. 22 with the contract scheduled to be awarded April 30.
In the interim a new vehicular ferry terminal was constructed. The project involved building access roads to the lake, constructing in-lake docks and studying dredging techniques. Operational since the end of January, the ferry operates 24-hours a day, seven days a week, crossing just south of the former site of the Lake Champlain Bridge. There is no charge to ride so as to help restore commuter, tourist and commercial traffic in the former Lake Champlain Bridge corridor.
As thousands watched in person, via the Internet and television, New York blasting subcontractor, Advanced Explosives Demolition (AED), used nearly 500 pre-set high-tech linear-shaped explosive charges to cut through the steel at 17,000 ft. (5,181.6 m) per second, causing the 80-year old span to implode in under 10 seconds.
Following a burst of bright light and a nearly simultaneous boom of more than 130 decibels, spans 4 through 9 — or more than 80 percent of the bridge — dropped into Lake Champlain. The fallen portions were quickly devoured by the icy waters. Those portions and the concrete piers that supported them will be removed by this spring along with the rest of the bridge. The lake in that area is expected to be open to navigational traffic in April.
The 2,184-ft.-long (665.7 m) Lake Champlain Bridge had been ordered closed on Oct. 16, 2009, when engineers who were repairing the span’s upper portion noticed an exposed crack in one of the previously submerged piers. It was determined that from 2005 to 2008 an inexplicable 14 in. (35.6 cm) of additional deterioration had occurred making the bridge unsafe and unstable. New York State’s Department of Transportation’s inspection schedule previously had shown underwater deterioration at the rate of roughly an inch every five years for approximately 20 years since New York and Vermont took over control of the bridge.
A Little History
The Lake Champlain Bridge (a/k/a/ Crown Point Bridge) originally was designed by the Boston engineering firm of Fay, Spofford and Thorndike. Two construction contracts were awarded: a $385,000 substructure contract went to Merritt-Chapman & Scott Corporation of New York City; and a $535,177 superstructure contract went to The American Bridge Company of Ambridge, Pennsylvania. Bridge construction began on June 14, 1928. Total cost, including land, materials and engineering services, was $1,149,032.
Some other facts about the Champlain Bridge are:
• It opened to traffic on Aug. 26, 1929, after a ribbon cutting ceremony on the bridge by New York Gov. Franklin Delano Roosevelt and Vermont Gov. John E. Weeks.
• Toll collection began on Aug. 27, 1929.
• Original bridge tolls were $1 for cars, $1 to $2 for trucks, $3 for buses, 25 cents for pedestrians and 50 cents for horse drawn vehicles.
• The bridge was owned and operated by the Lake Champlain Bridge Commission from 1929 to 1987.
• The Lake Champlain Bridge Commission was abolished in 1987 and ownership was transferred to the States of New York and Vermont.
• Upon the dissolution of the Bridge Commission tolls were eliminated and NYSDOT assumed maintenance responsibility.
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