FORTY years since the collapse of the Tasman Bridge, Tasmania will stop to mark the milestone.

media_camera The Tasman Bridge today.

To commemorate the exact time of the disaster on January 5, 1975, traffic will be blocked from the bridge, the span lights dimmed and a commemorative plaque unveiled.

The bridge will be closed between 9.15pm and 9.35pm on Monday, with a minute’s silence at 9.27pm to mark the precise moment of impact 40 years ago.

The lights on the bridge will also be dimmed during the minute to reflect the night 40 years ago when all the span lights went out.

Monday’s commemorations, which will also include the opening of an exhibition at Rosny Barn on the bridge disaster, are joint initiatives of Hobart and Clarence councils.

Hobart Lord Mayor Sue Hickey said the events were a fitting tribute to the 12 lives lost in the disaster and the ensuing hardships endured by a city split in two.

“This was a significant event in the history of Hobart and Clarence and so it is appropriate that it is marked with a formal commemoration,” she said.

When the 10,000-ton bulk carrier Lake Illawarra struck the Tasman Bridge, several pylons and a 73m section of the bridge collapsed onto the ship and river below.

Of the 12 people killed, seven were crew on the ship and five were in four cars which plunged from the stricken structure into the River Derwent.

Clarence Mayor Doug Chipman said it was timely to erect a plaque at the place of impact, where the bridge collapsed.

“People go across the bridge every day, but there’s nothing to say where the event occurred,” he said.

media_camera Cranes perches precariously astride the new piers ready to lift new girders to bridge the gap in 1977.

The unveiling of the plaque will be attended by Ald Hickey, Ald Chipman, representatives from police, emergency personnel and other agencies involved.

While the evening event will not be public, to minimise disruption to traffic, the earlier daytime exhibition is open to all.

The 11am opening of the exhibition at Rosny Barn will include the GTS Monaro which famously dangled from the severed bridge, which Frank Manley and his family scrambled from to safety.