|
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.
Confederation
Bridge
IMAX
Canadarm
Transcontinental
Railway
Pacemaker
Engineering
Week
|
