MONTREAL – The continuing deterioration of a supporting beam in one of Canada’s busiest bridges has prompted more emergency repairs.

A steel “super” beam will be used to prop up a girder in Montreal’s Champlain Bridge after a two-millimetre crack widened.

The crack was discovered last week.

Glen Carlin, the general manager of the corporation which oversees Montreal’s federally-run bridges, says the 75-tonne beam, which was delivered in 2009, will be installed by mid-December.

Carlin has previously estimated that 350 beams on the bridge are in different states of deterioration.

In the meantime, truck traffic will be restricted and speed will be reduced for all vehicles that use the bridge.

There will also be daily inspections on the bridge, which was built in 1962.

Plans are underway to replace the thoroughfare with a new structure in 2021. But federal officials are now looking at speeding up construction of the new bridge which will cost between $3 billion and $5 billion.

Every year, more than 50 million vehicles use the Champlain Bridge, which links Montreal with its south shore.

Transport Canada also says on its website that 6.2 million trucks make up 10 per cent of the bridge’s traffic and 200,000 buses also use it.

The federal department says the bridge was not designed to handle today’s high volume of traffic and the use of de-icing salt has contributed to corrosion and the degradation of concrete.