March 16, 2009

The 70,000 kilogram truss can be seen during installation. It is keeping a heritage building several metres off the ground in downtown Vancouver.

Innovation

Vancouver building suspended after financing falls through

JESSICA KERR

correspondent

Downtown Vancouver has become home to one of the more unique construction sites in the country.

Since November 2007, one of the city’s heritage buildings has been suspended six storeys in the air.

In November financing fell through for the $180-million Jameson House condo/office development, however construction had already begun.

A 21-metre deep hole had been dug at the site on West Hastings for the 37-storey tower’s foundation and parking garage.

To keep the nearly 90 year old Ceperley Rounsfell building from falling into the hole, it was enveloped in a steel truss and that’s where it remains.

The measure was intended to be temporary, however, as the company continues to try and secure new financing for the project, the building continues to hover several metres above the street.

The truss weighs 70,000 kilograms, measures 40 metres long, eight metres high and nine metres wide and cost about $2.5 million to construct and erect, said Bruce Simmonds, an engineer with LNS Services, the company that built the truss and worked on other aspects of the project.

“Our scope was to demolish the existing buildings, support the heritage buildings, and excavate and shore for the new building and parking garage,” he said.

Pacific Blasting Division carried out the demolition, LNS Services Division supplied and installed the truss, and Bel Pacific Division did the excavation and shoring.

The assembly and erection of the truss took about 10 workers eight weeks to complete, while the excavation took another six months.

The Jolly Taxpayer Pub had been demolished, creating a vacant lot next to the site, which was used as a staging area.

Before installation of the truss could begin, about 20 concrete filled caissons measuring one metre in diameter by 20 meters long were drilled into the sidewalk on Hastings and the back lane to support the truss.

The truss was fabricated locally by Kay-Son Steel Fabricators Ltd. in Coquitlam and trucked in pieces to the site and assembled on the ground in the staging area.

Once assembled, Simmonds said, the truss, which is made up of steel sections with bolted connections, was lifted into position above the heritage building using two cranes.

“The building basement concrete floor was removed and slots excavated to accept heavy steel needle beams under the building foundations at six locations across the width of the building,” he said.

Twelve Steel hangers were connected from the truss to the needle beams on both sides of the building.

Hydraulic jacks were attached to each hanger.

The system was then energized, he said, and the weight of the 1,200 tonne building was taken by the truss.

“The hydraulic jacking system is self leveling, such that each jack will take its appropriate amount of weight to ensure the building remains level,” Simmonds explained.

This allowed excavation below the building to begin.

While having the building resting on the truss was supposed to be a temporary measure, Simmonds said the structure could last for several decades.

“The truss was designed for seismic loads and should last 25 to 30 years or more,” he said.

Once the parking garage is built up to the underside of the building, and the truss and needle beams are removed, the roof of the parking garage will become the new basement floor for the heritage building.

The Ceperley Rounsfell building has Heritage A status, which is the City of Vancouver’s highest rating.

The facade of another heritage building, nearby on Hastings Street, was also partially rebuilt as part of the project.

Construction, however, remains on hold and the Ceperley Rounsfell building remains suspended in mid-air.

“This is a unique design,” Simmonds said. “I don’t know of anything similar to this in North America.”

The Ceperley Rounsfell building, was built in 1921 by Vancouver pioneer Henry Ceperley. It was being restored as part of the Jameson House condo/office development.

The aim of the project, which was designed to achieve LEED gold certification, is to restore and integrate two heritage buildings to create a mixed-use building with retail and restaurants on the bottom three floors, eight floors of office space and 25 floors of condominiums.

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