May 15, 2008

PCL CONSTRUCTORS

A new glass-and-steel tower will grace the century-old Victoria Memorial Museum Building in Ottawa.

Victoria Memorial Museum tower aims to complete architect’s original design

PETER KENTER

correspondent

A new glass-and-steel tower that will grace the century-old Victoria Memorial Museum Building in Ottawa aims to complete an original design by Dominion Chief Architect David Ewart.

When the building opened its doors in 1912, it featured a four-storey entrance tower visible from Parliament Hill.

The heavy sandstone structure, however, proved too much for the clay soil on which it was built, sinking slowly even as it was being erected.

The tower was removed in 1916 leaving only a two-storey entrance structure.

The new $10-million tower, referred to as “the lantern” is part of the $130-million federally-funded renovation of the Canadian Museum of Nature.

“The lantern is a tribute to the original tower in that it recreates the volume of the original structure, although not its character,” says Barry Padolsky of Ottawa-based Barry Padolsky Associates Inc., Architects, the company primarily responsible for project management.

“The original tower was extremely massive in appearance, which is part of the reason it had to be taken down. The heavy tower actually began to lean toward Parliament Hill and was pulling away form the building.”

The new design takes its cues from the soil conditions. The 540-tonne tower is supported by a series of steel piers sunk up to 35 metres into the clay soil.

A suspended steel and glass stairway will give museum visitors direct access to the building’s third and fourth floors.

A museum display, visible from the street, will grace the transparent tower which is being built to reflect current seismic standards.

“The hardest part is creating the interventions and enforcements within that limited space,” says Padolsky. “The actual construction is like architectural engineering dental work.”

PCL CONSTRUCTORS

An aerial view shows cranes at the ready as the 50-tonne steel roof of the “lantern” tower of the Canadian Museum of Nature is assembled on-site.

And like a dental procedure, the difficulty began with the drilling by PCL Constructors Canada Inc.

“When they were drilling, they encountered rocks and other original construction debris,” says Xavier Rankin, Deputy Project Director for the VMMB Renewal Project.

“The layout grid pattern for the steel supports is very tight, so if you end up going off centre, you end up drilling where the next one is supposed to be.”

Four pairs of massive steel columns, two-thirds of a metre in diameter and 11 storeys high, now rise eight storeys above the entrance hall.

The specially-designed hollow columns also act as part of the building’s ventilation system.

The lantern’s steel roof, weighing more than 50 tonnes, was delivered in four parts and assembled on site, then lifted into place by cranes at the beginning of May.

The tower’s staircase, which also helps to brace the columns, is currently under construction.

A million dollars worth of triple-glazed specialty glass has already been delivered to the site and is scheduled to be installed through the summer, into September. The lantern tower is scheduled for completion this fall.

The relatively short construction phase follows a long preparation process, says Rankin.

“There was an incredible amount of time spent by the architects, by the steel fabricators and by PCL in reviewing the details of how it would all fit together, ensuring that the trusses were built to specifications and that the visible steel columns had the architectural smoothness required to suit the aesthetics of the design.”

The five-year renovation of the museum is scheduled to be completed in time for a grand re-opening in May 2010.

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