New Lake Champlain Arch Bridge ensures efficient Transport Connection
The new Lake Champlain Bridge was opened to traffic on November 7th 2011, replacing a bridge built in 1929 that had to be closed unexpectedly in October 2009 due to the discovery of severe structural defects. The new bridge had to be completed quickly because once the old bridge had been closed, crossing Lake Champlain was very time-consuming and only possible by ferry.
Context
The elegant arch bridge connects the US states of Vermont and New York.
Construction of the new bridge started in June 2010. The structure is an arch bridge with a concrete substructure and a steel and concrete superstructure. The bridge’s substructure consists of two concrete abutments and seven concrete piers, six of which were constructed directly in the lake on 32 drilled shafts with diameters of 1.8m each. After completion of the shafts, a reinforced concrete pile cap was placed at water level, allowing steel girders to be subsequently installed on the piers.
The principal feature of Lake Champlain Bridge is its 123m (403.5ft) long network tied arch span. The arch structure was prefabricated near Port Henry in the state of New York and then floated into position on the Lake. Hydraulic lifting jacks then raised the span to its final position.
In order to minimize the weight of the arch for lifting, the center span was erected without its concrete deck, and the precast concrete panels for the deck were only installed after the arch structure had been lifted into position. Even without the bridge deck, the arch structure had a weight of 900t, posing a logistical challenge.
Solution
DYWIDAG supplied a total of 64 Dyna Grip Stay Cables consisting of 7-0.6“ DYWIDAG Tendons for the arch structure of Lake Champlain Bridge. Initially, the stay cables were placed in the arch structure and partially tensioned. Only after the arch had been lifted to its final position were the stay cables tensioned to their final force. In addition, DYWIDAG also supplied and installed the post-tensioning systems for the precast concrete segments of the bridge deck and carried out the tensioning and grouting work of the systems.
Due to the limited timeframe, the installation and tensioning work had to be realized within a very limited schedule. Thanks to the dedication of all the specialists involved, work could be completed efficiently and safely within the determined time line.
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