The design and construction of the Confederation Bridge from Prince Edward Island to New Brunswick is one of the engineering marvels of this century. The Canadian-led team of engineers faced and overcame many challenges.
For example, the design engineers had to achieve a 100 year design standard in all aspects, including the bridge's resistance to the combined effects of wind, waves and ice. Given that the codes for most bridge design meet 50 year standards, this meant deriving design criteria and establishing a new design code that is effectively seven to 22 times more stringent than most North American design codes.
As a result of the demanding conditions and performance requirements, the materials engineers had to rise to the challenge of the new design code. For example, high production, high performance concrete had to be developed to meet the harsh environmental conditions in the Northumberland Strait. Concrete strength is measured in mega pascals; the concrete used for most of the bridge was 55 mega pascals in strength as compared to the 30 - 35 mega pascal concrete of most construction jobs. The 20m diameter ice shields at the water level were monolithic with the piers required and were constructed of 90 mega pascal concrete.
The construction engineers, too, faced their own challenges. They were required to build a 13km bridge in 32 years (with a construction season that lasted only six months each year) to new and exacting standards. The construction engineers met this challenge by precasting the massive elements on land, then assembling the 185 main components in the strait with a fleet of giant marine equipment. The principle isn't new but consider that some of the components weighed up to eight thousand tonnes each and that their positioning had to be accurate within 20mm. Even with the new design standards, the construction engineers maintained a blistering pace of more than 2 km of construction per month.
Ultimately, high engineering standards, creative thinking and a condensed construction timeframe tell only part of the story. The team of Canadian engineers was fully aware of the historical, constitutional and cultural significance of a permanent link between Prince Edward Island and mainland Canada. For these reasons, the Confederation Bridge is truly one of the greatest engineering achievements of the 20th century.
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