Extreme Cold, High Winds and Heavy Concrete
July 22, 2025
By: Connie Clearwater
The northeast stairwell removal at the Glenbow Museum in Calgary, Alberta, Canada, was a unique and challenging demolition project that spanned just over 12 months and required careful planning, patience and perseverance from the team. There was no simple solution for what this project required. The former emergency stairwell was constructed of 1.8 million lbs. of reinforced concrete that utilized a tower crane for its removal.
The Glenbow Museum has often been described as a “concrete bunker.” Detailed drawings were not available, and there was very little information regarding the outer concrete panels attached to the building. A preliminary investigation was conducted before the start of the project; however, the team continued to discover something new with each panel that was removed from the building. The thickness of the concrete was inconsistent.
As with all projects, safety had to be the top priority, especially because of the museum’s location on one of Calgary’s busiest and most heavily populated streets. The crew had to be extremely careful with the removals and could not drop a single piece of concrete.
The scope of work included an engineered plan and complete demolition of the eight-story, 125-foot stairwell, as well as the removal of the building envelope, structural members and the creation of a new opening for an interior feature staircase spanning all eight levels.
A highly detailed plan was designed by our team of demolition engineers and included the placement of coring holes, rigging and customized hydrolift solutions for the exterior panel removals. No two floors were the same, and no two concrete pieces were identical. In some spots, the concrete was 8 inches thick, and in others, it was 12 inches thick, which varied the weight. The largest panel was 36,000 lbs. — 20 feet high by 12 feet wide. For each floor, NDA member Priestly Demolition Inc. (PDI) separated the massive concrete spans into 20-panel sections (160 in total), with each panel weighing between 20,000 and 36,000 lbs.
The crew then had to bush-hammer the remaining concrete on the existing structure once the panels were removed for the new concrete to adhere to. Precise saw cuts were important when separating the building from the stairwell and had to be perfect with no over-cuts. This was to ensure the integrity of the concrete where the museum’s new main entrance will be built.
With shoring installed, PDI was able to cut out the floors, stairwell and walls. Additionally, the landings, stair treads and a slab portion had to be separated from the building, and the saw cutters worked in conjunction with the tower crane to pull out what concrete they could (within capacity limitations). Lifting concrete very close to the building was a challenge, especially with different spreads on the slabs. Proper rigging, communication and close attention to detail were very important to the success of the project.
Removing the Panels
Prep time for each floor was one to two weeks, depending on complexity. The crew made vertical saw cuts on the panels using a wall saw, and the hydrolift climbers drilled and cut the panel pieces. Next, the team would attach the steel stitching to the cuts to ensure there was no shifting within the pieces before they were ready to lift. Once complete, the evening crew would come in to make the final horizontal cuts.
Depending on how much a particular panel would weigh, the cutters would then set up a saw track on the bottom piece of concrete to finish the separation. The coring holes were drilled for the rigging points, and steel cables were run through the concrete panels so that the PDI team could safely pick up the panels with the 165-ton crane positioned on the road below and carefully move each piece to the trailer bed. Road closures were allowed only for this portion of the project when the massive pieces of concrete panels were being removed and transported off-site.
Challenges
One of the biggest challenges was the very limited access PDI had inside the project footprint. With various phases of demolition and construction happening simultaneously on-site, there were a number of sub-trades, museum staff and contractors using the small space. Street closure was not an option because Steven Avenue is one of the busiest pedestrian streets in downtown Calgary and is required to stay open for emergency access.
On the other side of the stairwell is First Avenue, which is also required to stay open for traffic because it is one of the main arteries leading into the downtown core and the Scotiabank Saddledome sports and entertainment venue.
The second biggest challenge with this project was the weather and the extreme cold of the Rocky Mountains, which Alberta is famous for. During the winter months, temperatures can go as low as -40 degrees Celsius. “With laborers on the outside of the building attempting to remove the concrete panels, it becomes a health and safety concern for the crew’s well-being, and often the job site will have to be shut down,” says Taylor Jones, PDI foreman. The tower crane has additional restrictions during extreme weather conditions that shut it down for safety reasons as well.
Saw cutting is also difficult in winter weather because it requires water to suppress the dust. When you mix water with freezing temperatures, the obvious happens. PDI was able to mitigate the issue with heated hoses and frost fighters to keep the brain boxes for the saws warm enough to pump water without too many technical issues.
During the summer months, Alberta has high Chinook winds, which become a problem when attempting to move large, heavy pieces of concrete off the side of a building with the use of a crane. Weight control and wind impact on the loads were something the team had to pay close attention to.
Special considerations were also made for the stairwell removal because of the necessary climate control within the building, as many of the museum’s artifacts remained on-site. The building had to be weather-tight before any removals could begin. Add to the list of challenges the fact that the museum is also attached to a large convention center; therefore, noise and vibration had to be monitored and limited so as not to disrupt or disturb ongoing conventions next door.
Part of a Whole
The northeast stairwell demolition of the Glenbow Museum was just part of a complete makeover for the museum, both inside and out. “The project was a challenge, but the team is very proud of the specialized work they performed on this site and is excited to be a partner in the progress of the museum. PDI is thankful to EllisDon Construction for entrusting them with the demolition, on behalf of the multiple owners and donors who have made it possible,” said Kevin Hickman, PDI superintendent.
The modernization will provide many immediate direct benefits to the Glenbow Museum and will support diverse exhibitions, flexible programming and increased events. It will include updated and current systems that serve to protect Glenbow’s collections and critical assets. It will create a welcoming, accessible and healthy environment for its employees and patrons while strengthening connections with the immediate and greater Calgary communities.
Land Acknowledgment
Glenbow is located on Treaty 7 territory and respects the history, languages, traditions and cultures of the Nations on whose traditional land we reside. The area, traditionally called Moh’kins’tsis, is home to the Niitsitapi from the Blackfoot Confederacy, which includes Siksika, Piikani and Kainaiwa, the Îyârhe Nakoda of the Bearspaw, Chiniki and Goodstoney Nations, and the Dene of the Tsuut’ina Nation, as well as the Métis Nation of Alberta Region. We further acknowledge the vital connections we have to other Indigenous people (including other First Nations, Inuit and Métis) whose visual and intangible culture is represented in our collections and exhibitions.