Preserving the Past, Protecting the Future: Centre Block's Restoration

Preserving the Past, Protecting the Future: Centre Block’s Restoration

Ty Burke

PSPC/SPAC

Parliament’s Centre Block isn’t just a building, it is an icon. Its sturdy stone façade is a symbol of Canadian democracy. But the current structure was built in 1920, and a lot can change in a century. Back then, Canada didn’t even have building codes, and climate control technology like air conditioning was still decades away from wide use. Bringing the historic building into the 21st century will be a big undertaking, and it is already well underway. �Ӱ�ԭ�� engineering graduates are part of the team that is revitalizing Centre Block so it can serve Canadians for the next hundred years—or even longer.

Parliament Welcome Centre: Structural start of the crane base pour.

“Centre Block is a very special structure, but it is an old building, and it predates any code requirements for seismic—or even snow piling, for that matter,” says Dan Carson, the lead structural engineer for the Centre Block restoration project. Carson has been with engineering, a partner in the joint venture lead design team CENTRUS, since 1978—not long after he graduated from �Ӱ�ԭ��’s and programs.

The project will update Centre Block to meet all current code requirements and is also adding base isolators to protect it from potential earthquake damage. Base isolators are in fact large rubber elements installed beneath a building’s foundation to act as shock absorbers. When the ground shakes, the base isolators bear the brunt of it, allowing the building above to sway slowly and escape major damage. The technology is rare in Canada but has been used in thousands of buildings in Japan, New Zealand and the United States.

“Ottawa is an area of moderate seismicity, and it is not as active as some seismic zones, but there is a risk of earthquakes,” says Carson. “And Centre Block is an old, unreinforced stone masonry building. The base isolators help mitigate the risk associated with earthquakes.”

The rehabilitation project plans to construct a new basement under Centre Block. “A major excavation is required to facilitate this construction,” says William Springle, a graduate of �Ӱ�ԭ��’s Bachelor of Civil Engineering program who recently joined WSP to work on the project. “Essentially, the building will be supported on piles while we excavate. You really get a sense of the scale of the project, and how unique it is.”

There are few parallels between Centre Block and the other projects Springle has worked on in the past. Modern structures are very orderly, with everything built according to plan. But in Centre Block, every element is unique. And that presents challenges both below ground level and above it. For Carson, integrating new systems like sprinklers, ducts, plumbing and wiring is like solving a giant puzzle.

To make way for modern building systems, the structure of Centre Block needs to be modified. Many existing steel beams need to be cut to create space, and additional beams are needed to support parts of the building.

“Rather than just getting rid of the old steel beams, we wanted to figure out how to reintegrate them into the building,” says Yasmin Anderson, a graduate structural engineer on the Centre Block project and a graduate of �Ӱ�ԭ��’s . “It wasn’t just out of a desire to preserve the material for heritage reasons, but also for sustainability.”

So, Anderson and her colleagues at CENTRUS cataloged all the existing beams, and the new beams that would need to be put in place. An algorithm calculates the different permutations of how to cut up old beams so that they’d fit with structural demands.

“Re-purposing the existing materials reduces the amount of steel that we need for the project,” says Anderson. “We figured out how to use the highest percentage of the metal removed from the building to get the most carbon savings. The initiative brings together a lot of the things that are important about this project—cutting-edge technology, sustainability, and a heritage mindset.”

Centre Block is an enormous building, and supporting the structure during the renovations is an engineering feat in its own right. Construction on the current building began just a few months after the fire of 1916. “It burned in winter, and they were building by August of the same year. It happened very quickly by modern standards,” says Anthony Urbisci, a structural designer with WSP and a graduate of �Ӱ�ԭ��’s Bachelor of Civil Engineering and Master of Structural Engineering programs. To make way for modern infrastructure, the existing building needs to be supported. Urbisci is part of the team that reviews the design of temporary work required to do this. “As we take things apart and put them back together, we are maintaining the heritage nature of the building,” he says. “The whole goal of this project is that by the time it’s done, you won’t notice that much of a difference.”