MONTREAL - Drivers who wanted to take the Mercier Bridge Thursday got a bit of a shock when Transport Quebec unexpectedly and without notice decided that lanes heading to the South Shore would not be open after all.

The plan, only announced Wednesday, was for one side of the span to be closed for a 24-hour period for repairs. While work was being done the other side of the bridge was supposed to handle one lane of traffic in each direction.

Instead when the southbound span closed at 5 a.m. Thursday, traffic from Montreal was diverted to other bridges.

Transport Quebec says there are no plans to alter the traffic pattern for the drive home, so people who took the Mercier Bridge into Montreal from the South Shore will have to find another way home.

The repair work on the Mercier Bridge is scheduled to wrap up at 5 a.m. Friday.

Transport Quebec said it is reinforcing one gusset plate unrelated to the ten gusset plates reinforced this summer.

"We're working on a gusset plate where we did not work or intervene before," said Caroline Larose of Transport Quebec.

In mid-December, the transport agency replaced one broken bolt on a gusset plate that had been repaired during the previous construction project.

"There are approximately to 100 bolts on one gusset plate, so having one broken bolt for us is, let's say, a minor hiccup."