Cleanup continues after Ottawa parking garage collapse

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Following the partial collapse of the Slater Street downtown parking garage, a “partial demolition” took place on Thursday morning according to city officials.

As the remains of the collapsed vehicular ramps were demolished, owners of the approximately 50 vehicles trapped inside were still in the dark.

Ann Burchell’s vehicle is in the garage. She said she could see her car undamaged inside the structure, but can’t get to it. She secured a rental car through her insurer Thursday afternoon. She has heard only silence so far from parking management company Indigo Park Canada and property owner GWL Realty Advisors.

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“I haven’t received any updates from the building owners despite having provided my contact information,” Burchell wrote in an email.

She shared that she’s part of an email group with other vehicle owners whose cars are trapped, but that “no one has shared getting any information from the owners, or a timeline.”

Meanwhile, details of the 36-year-old parking structure’s history have come to light.

Completed in 1989, the city has not inspected the parking structure since it was completed. John Buck, chief building official for the City of Ottawa, said in a Thursday statement that it is the responsibility of property owners to ensure the structure is properly maintained and in a structurally sound condition.

Buck said “Building Code Services’ role is to ensure any demolition and remedial structural work that may be necessary is carried out in accordance with the Building Code Act. Further details on the status of the parking garage are best addressed by the owner.”

GWL Realty Advisors and Indigo Park Canada have been contacted by the Citizen but neither group has provided a comment.

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Buck said the timing on cleanup is not determined. After the partial demolition, construction crews will remain on site to clean up and remove debris. Slater Street’s reopening to traffic is “dependent on the completion of this work.”

He said city officials are “working closely with the property owner on next steps.”

GWL Realty has owned the property and the garage on it since 2003. Last June, city council approved a plan to construct a pair of residential towers, 25 and 26 storeys tall, on the site of the garage. The proposal succeeded a scrapped plan from 2003 to construct two office towers on the site.

In 1987, before the parkade was built, the Citizen reported that Ottawa officials supported the garage’s construction to ease the city’s parking shortage, especially for the Sparks and Bank street areas. The lot was then city-owned.

Two months later, the city handed the land, valued at $9.5 million, over to developer Arnon/Olympia York on the condition that it build a parking garage with at least 500 spaces to help ease the downtown’s parking shortage.

The Citizen reported that “under the agreement, Arnon/Olympia York can tear down the garage for another development, so long as it provides 633 underground spaces as part of the project.”

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The existing four-storey, 400-space structure was finished in 1989, and future development never came to the site.

In June 2024 the Centretown Buzz reported that the now-collapsed parking garage was dry assembled with precast parts, and was intended to be easily deconstructed and removed when the new office tower was built.

“That makes a lot of sense,” said John Gardner, professor emeritus in uOttawa’s department of structural engineering, who said the garage was likely “getting towards the end of its life.” He is not involved in the structure’s assessment.

“If this structure is 36 years old, it means it was probably designed 40 years ago, and design attitudes have changed,” Gardner said.

He said that like most structures in Canada, the parkade was likely engineered for the amount of snow load seen on the roof before its collapse, but that the buildup “sure as hell would not have helped.” He added that the condition of the precast concrete components, including a fallen facer seen leaning against the west wall of the structure, looked in good shape.

“There’s a piece of the roof parking garage there and the concrete looks excellent,” Gardner said while looking at a drone shot of the site.

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However, Gardner said modern building techniques have evolved to account for earthquake risks, such as improved tiebacks to help with rigidity. He said precast components in that era usually weren’t assembled with the same standards.

“You take them onto site and you lift them up with a crane and you put them on ledges and you hope it stays on the ledge,” he said.

In 1985, Gerard Litvan, a senior scientist in the National Research Council, completed a survey of 215 parking garages across Ottawa, Toronto and Montreal. He determined only three “were built to withstand the ravages of salt.”

“Of the 30 Ottawa parking garages included in the study, only one showed no sign of salt damage,” Litvan told the Citizen in 1985.

At the time, Litvan said when the building boom in parking garages began in the 1950s, road salting wasn’t done as extensively and nobody realized its damage potential.

Gardner said road salt corrosion and temperature effects could have been contributory causes.

“I imagine there’s a lot of salt water [that] got through there and rusted away at whatever connection was there, which is probably mild steel,” Gardner said.

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