Confederation Bridge
The Confederation Bridge or Pont de la Confédération is a box girder bridge which was opened in 1997 and is a two-lane toll bridge that carries the Trans-Canada Highway between Borden-Carleton, Prince Edward Island and Cape Jourimain, New Brunswick. The unique feature of this bridge is its location as the Northumberland Strait is often enveloped in ice. At 8 miles long, it’s the longest bridge over ice-covered water in the world, making it an impressive accomplishment of engineering world.
-
The Fixed Link
Epekwitk Crossing
Abegweit Crossing
The Span of Green Gables
-
Multi-span post-tensioned concrete box girder
-
Northumberland Strait
-
12.9 km (8.0 mi)
-
1993-1997
-
C$1.3 Billion
-
2 lanes of NB Route 16/PEI Route 1 (Trans-Canada Highway)
-
4,000 (Approx.)
The Confederation Bridge is a multi-span balanced cantilever bridge with a post-tensioned concrete box girder structure. Most of the curved bridge is 40 m (131 ft) above water with a 60 m (197 ft) navigation span for ship traffic. The bridge rests on 62 piers, of which the 44 main piers are 250 m (820 ft) apart.
The bridge is 11 m (36 ft) wide. The speed limit on the bridge is 80 kmph (50 mph) but might differ as per wind and weather conditions. while travelling at the speed limit, it takes about 12 minutes to cross the bridge.
Design
The bridge, designed in such a complex manner with multi-span concrete box girder is 12.9 km in length. It consists of multiple rigid frames and simply supported drop-in spans. The spans are separated by expansion joints and bearings to accommodate the movements associated with loading, creep, shrinkage and thermal effects. Each span consists of a variable-depth box girder, with a depth of 14.5 m at the pier location and decreasing parabolically
to 4.5 m at the end of the span. The width of the box girders varies from 5.0 m at the bottom to 7.0 m at the top. The piers for the main girders are founded in upward of 35 m of water and in current velocities approaching 2 m/s. The bridge has a typical clearance of 40 m above sea level, with the exception
of a navigation span which is 60 m above water. The deck width of the bridge is 11 m, providing one traffic lane and one wide shoulder in each direction.
Construction
The construction was carried out by a joint venture of Ballast Nedam, GTMI (Canada), Northern Construction and Strait Crossing Inc. beginning with preparation of staging facilities in the late 1993.
Bridge components were built through the year 1994 to the summer of 1996, and placement of components began in late 1994 until late 1996. Approach roads, toll plazas and final work on the structure continued until the spring of 1997, at an estimated total cost of $1 billion.
All bridge components were constructed on land and the Amherst Head staging facility was where all large components were built, including the pier bases, ice shields, main spans and drop-in spans. The Bayfield facility was used to construct components for the near-shore bridges which were linked using a launching truss extending over shallow waters almost 2 km (1.2 mi) from the New Brunswick shore and 0.5 km (0.3 mi) from the Prince Edward Island shore.
Extremely durable and high-grade concrete and reinforcing steel were used in the construction of the pre-cast components, with the estimated lifespan of the bridge being in excess of 100 years. It was also designed as such that it could withstand iceberg impacts, as a deflection cone encircles each pillar at the point when it meets the water surface that would cause an iceberg to bounce off. Their sheer size and weight required strengthening of the soil base during the design and preparation work for the Amherst Head staging facility, as well as the use of a crawler transport system to move pieces from fabrication to storage and onto a nearby pier. These crawler transports, using specially designed teflon-coated concrete rails, were nicknamed lobsters from workers.
All major components were lifted from the Amherst Head staging facility, transported and placed in Abegweit Passage using the HLV Svanen, a Dutch-built heavy lift catamaran, which during the construction of the fixed link was, as per reports the tallest man-made structure in the region. HLV Svanen was custom-built for use on the Great Belt Bridge in the early 1990s, Denmark’s largest construction project, and was modified at a French shipyard before working on the Northumberland Strait Crossing Project.
Construction of the fixed link required over 5,000 workers ranging from labourers and specialty trades, to engineers, surveyors and managers.
Finishing
After completing the structure on November 19, 1996, SCI worked throughout the winter, paving the bridge deck, placing bridge concrete barrier guardrails which also act as wind barriers, placing bridge deck and navigational lighting, constructing the Borden-Carleton toll plaza, and finishing the New Brunswick and Prince Edward Island approach roads. In separate construction, the federal and provincial governments built a new commercial and tourist development on the abandoned CN rail yards in Borden-Carleton, with phase I of this facility opening in spring 1997 as “Gateway Village”. New Brunswick has never received similar federal support to improve the economy of Cape Tormentine, which has become a shadow of its former role in PEI transportation history, although in recent years a new eco-tourist and visitor centre was opened on Jourimain Island near the western end of the bridge.
References
https://www.cbc.ca/news/canada/prince-edward-island/ confederation-bridge-under-microscope-at-engineering-conference-1.632942
https://www.thecanadianencyclopedia.ca/en/article/confederation-bridge
https://study.com/academy/lesson/confederation-bridge-history-type-facts.html
https://www2.engineering.com/Library/ArticlesPage/tabid/85/ ArticleID/61/Confederation-Bridge.aspx
https://www.sciencedirect.com/topics/engineering/confederation-bridge
By -
Tuhina Chatterjee, Associate Editor - Civil Engineering and Construction Review
