Canadian Consulting Engineer

The New Eccentrics

December 1, 2003
By Bronwen Parsons

Strange things are happening in Toronto. Walk down McCaul Street going south from Bloor, pass Henry Moore's brooding stone giant outside the Art Gallery of Ontario, weave your way around pedestrians a...

Strange things are happening in Toronto. Walk down McCaul Street going south from Bloor, pass Henry Moore’s brooding stone giant outside the Art Gallery of Ontario, weave your way around pedestrians and pots of bright flowers outside the Chinese grocery stores, and suddenly you come across an astonishing site. Raised high on painted tube stilts, mounted 26 metres above the street over existing buildings, is a huge oblong box. Designed by British architect Will Alsop with local architects Robbie, Young and Wright, the new Ontario College of Art and Design is intended to shock. As an admiring architecture professor put it earlier this year: “idiosyncratic, braver, courageous. … there is no other building like it in North America.”

A subway stop north, among the grand buildings and wide vistas of University Avenue and Bloor Street West, another very odd structure is about to take shape. The venerable grey stone blocks of the Royal Ontario Museum are giving birth to a startling “crystal” addition. The multi-planed explosion of glass and metal is the work of New York architect Daniel Libeskind with Toronto architects Bregman and Hamann. Libeskind became known internationally when he designed the Jewish Museum in Berlin during the late 1990s — another building that is seemingly chaotic, deliberately defying not just gravity, but all our notions of order and rationality. He is also the architect for probably the most important project of our time: redeveloping the World Trade Center in New York City.

The art college and museum additions are so unorthodox they are drawing huge public attention, just as their owners and architects intended. But there is more to these projects than meets the eye. The spotlight falls on the architects’ originality, but there is a great deal of engineering involved to make the buildings work. The eccentric structures might not look functional, but they have to perform just as well — if not better because they are under so much scrutiny — than any conventional building. They have to be safe, afford shelter from the rain and elements, and provide a comfortable environment for the occupants inside. Failure in any one of these areas is not permissible. And that of course is where the consulting engineers step into the breach.

In both buildings, the structural engineering, the skeleton of the building, is the most dramatic engineering component. But the mechanical and electrical engineers who have to fit in the service infrastructure — the blood and nerves — around these highly irregular frameworks are also working in unfamiliar ways and literally have to ‘step out of the box.’


Royal Ontario Museum

At the Royal Ontario Museum, structural engineers Halsall Associates of Toronto have been working with Arup of the U.K. to fit Libeskind’s 3,700-s.m. crystal vision into and over the staid masonry H-block of the 1921 building.

“A design like this always pushes the limits,” says Neb Erakovic, P.Eng., project manager at Halsall. “We walk on the line between the feasible and non-feasible.” Apart from tying two very different types of structure together — the old and the new — the engineers are dealing with an architecture that defies conventional notions of building.

The “Michael A. Lee-Chin Crystal” comprises five intersecting, self-stabilizing volumes, explains Erakovic. One volume is the entrance, two larger ones are galleries, a fourth vertical volume contains the main stair and elevator shafts. A fifth volume rides over the historic building and houses the restaurant and some mechanical spaces. The intersections create an internal void or “spirit house,” and the horizontal floors act like a diaphragm, tying the walls.

The 1911 building’s structure is being augmented by new columns and stair cores, but only sliding bearings on top will connect it to the crystal.

The five volumes of Libeskind’s addition intersect in a thousand different ways, so to work out the details of the steel frame, the “diagrid” was created. “In this building it’s hard to say whether we’re designing walls or floors,” says architect Paul Gogan of Bregman and Hamann, the firm that enlisted Halsall on the project.

Wherever the inclined planes meet there are complex three-dimensional design issues. “Sometimes there are six or seven members at the same node,” says Erakovic. “With old-fashioned two-dimensional thinking, we wouldn’t be able to do this job.” They rely on the computer’s calculating power and sophisticated software packages containing a huge database of numbers. They are also working closely with the steel fabricator, Walters, to design the most effective connections and keep costs down.

Electronic communications between the team are critical on a project of this complexity. “The architect is creating volumes,” Erakovic explains. “Converting those volumes into something structural — which can resist the forces of nature and stand — is done entirely by file transfer between Libeskind, Arup and us. Then the design goes to field detailing.” The next stage is virtual design. “Teleconferencing will allow us to ‘meet’ and using video models to virtually fly through the design and look at it in three dimensions,” says Erakovic.

Even with such extensive computer simulation, the project demands a much higher degree of attention from the engineers than a conventional building. With no standard components there are myriad details. “We have to start from the basics,” says Erakovic. “You cannot create one wall and replicate it somewhere else.”

The endless detailing could become tedious, but the engineers seem to find that the thrill of working on such a unique design is well worth the sacrifice. Erakovic is clearly in love with the project. He came to Canada from Sarajevo, and has worked on other high profile buildings here and elsewhere, including a 435-m tall tower in Tehran and a large bank in Moscow.

“Working on this is my pleasure … staying late, working hard, facing issues…. I guess that’s what really makes our lives different. Just doing simple boxes would not be my ideal world — at least at this stage in my career.”

Erakovic has also enjoyed the experience of working with Arup, the high-profile U.K. engineers. “It is really exciting,” he says. “Not only are their engineers top-notch, but they also employ scientists and mathematicians with specialized knowledge. And their presentations are very impressive.”

For the mechanical engineers, The Mitchell Partnership, fitting the service conduits and equipment into Libeskind’s irregular crystals is no picnic. Still Bob Shute, P.Eng., a partner in the firm, is also excited to work on the project. Described by one of the architects as “like a kid in a candy store,” Shute says he enjoys: “the technical challenge of innovation, the feedback from a client that cares, the politics of a multi-national team.”

Libeskind’s original concept showed the exterior walls as mostly glass. While the image was aesthetically pure, critics were quick to point out that the transparent walls could be a big problem from an indoor environment point of view, creating large heat gains and losses, not to mention the damaging effects of sunlight on the artifacts. Now the crystal exterior has been redesigned with only 20 per cent glazing, in the form of irregular, elongated clear windows and skylights. The rest is clad in aluminum.

Shute’s team has had to start from first principles. “Nothing is standard within the crystal. All the usual knowledge is thrown out the window — if you can find the window,” he laughs. Take one aspect of the mechanical design: “Our aim is to minimize the distribution of the ductwork from the fan room,” he explains. “Instead of 90 degree elbows, the ducts come out of limited equipment space and we have to sort out a bowl of spaghetti.”

Unlike the structural engineers, the mechanicals have to interpret three-dimensional problems into two-dimensional drawings. They meet regularly with Vanbots the contractor to get feedback, says Shute, and the drawings are issued very frequently — some on an ftp site so that
the full team can access them. Libeskind’s office — used to designing odd angles and planes — also has a library of documentation available to the local engineers.

Controlling the budget and scheduling in these circumstances may be the most difficult challenge, suggests Shute. “So much of our industry is standardized, but now you’ve lost that comfort zone.”

The crystal will have a separate air-handling system from the 1920s building. The addition will have a quiet, low-velocity displacement air distribution system, in which the air is drawn in from a concrete underfloor plenum and rises as it picks up heat in the occupied space. The radiant heating is recessed at the perimeter to keep the interior spaces clear. There will be distributed digital zone controls interfaced with the existing building management system. As for fire protection, Shute says that the crystal really functions as a five- or six-storey interconnected space much like an atrium and it will have “as comprehensive a smoke control system as you see anywhere.” The lighting and power systems will be distributed along with the mechanical conduits through the concrete floor plenum.

Lighting a space with such irregular geometry is a challenge for the electrical engineers. There is “no comparison” with a standard office building project, says Jerry Mobilio, the project manager at Mulvey + Banani of Toronto.

With daylight entering through irregular skylights to hit sloping walls and roofs, it is extra difficult to balance the ambient light with the exhibit lighting. “Once daylight hits a skylight it does various things,” says Mobilio. “It could come down at 90 degrees, or in different ways.” To manage the problem they are using zone lighting controls and daylight sensors that will, for example, lower the light levels in areas where the sun is shining in and raise them as twilight falls. Mobilio’s team also relies heavily on computer analysis to engineer the design.

There is always tension between the architects and engineers on any building project, but is that stress ratcheted up a notch when the architect has an international reputation and there’s so much at stake?

Like the other engineers, Mobilio relishes the experience: “Studio Daniel Libeskind really knows what they want, and it makes our lives easier when architects know what they want, when they are interested in what lighting designers have to say.”


Ontario College of Art and Design

At the Ontario College of Art and Design (OCAD), the college’s project director, Peter Caldwell, argues that the new block of 8,400 square metres of design studios and offices called the Sharp Centre for Design is not so much “weird and wacky” as extremely functional. In fact, he says, “it’s basically a two storey building.”

Caldwell may be overstating his case. Even Caldwell acknowledges that the project is “heavily engineered.” How else would the box cantilever out from the core in that astonishing way, stretching out on steel beams 1.2 metres deep and 32 metres long — beams that had to be imported from Germany in order to meet the tight scheduling? Plus there are those legs — long, tapered tubes that rise 12 storeys high, painted in different bright colours of intumescent paint. The legs are made from 1″ thick steel pipe normally used in the petroleum industry and obtained from the U.S. Viewed from the air or from the ground the building resembles some giant urban insect.

The audacity of the design is matched by that of its architects. When Will Alsop and company presented their “flying rectangle,” also known as the “tabletop,” to the college five years ago, no-one but the design team had seen it until that point. On that same “scary day” Caldwell had to present the drawings to the college’s board of directors and to the public. That the local activists in the community accepted such a blockbuster of a building is remarkable, but Caldwell believes it was because they were involved in the design from those early stages. Wind studies eased their fears about shadow-casting, and the people who live opposite in condominiums along McCaul found they would still be able to see their beloved neighbourhood park through the gap below the flying rectangle.

Alsop wanted the six pairs of leaning legs to have a random placement, which was a challenge for the structural engineers, Carruthers and Wallace. Paul Sandford, P.Eng. of the firm explains that the soils in this area are shifting and unstable, so the legs rest in concrete caissons embedded into bedrock 18 metres below grade. The caissons are in a triangular pattern, interconnected to form in effect three-dimensional A-frames. To test the supports, the contractor, PCL, built a full-size test caisson and jacked it against the measured loads.

First, though, the architects and engineers had to agree on where to put the legs. Isabel Brebbia from Alsop’s studio says the exchange with the Canadian engineers went well. “We worked quite closely on the exact position,” she says. “They would test an option and send back results, and say this leg has to move here or there.” In one location the college’s high-voltage substation was in the way of a column and was moved.

“It was certainly interesting for our firm to work on a project as architecturally unusual as this one,” says Chris Andrews, P.Eng. of Carruthers and Wallace. “There’s only one other building that is visually at all like it in the world, I think.”

In order to resist wind uplift and seismic forces, Sandford says they made the structure “as rigid as you can make a box.” Deep trusses go in both directions forming the two floor levels.

Compared to a standard building, the flying rectangle has an extra facade exposed to the elements, so on the rectangle’s underside they added a soffit 1.2 metres deep. The soffit insulates the building against heat and cold from below, acts as a service plenum for the plumbing and electrical conduits, and is mechanically ventilated in order to guard against the growth of mould.

Otherwise, the rectangle is quite conventional from a mechanical and electrical point of view. Tim Jantzi, P.Eng. of MCW Consultants of Toronto, the mechanical and electrical engineers, says it has rooftop air-handling units for heating and cooling, and the electrical, water and waste services are threaded up through the big services core as they would be in any building. Here the core is exposed to the elements, but that didn’t present any huge technical challenges. The biggest difficulty, he says, was phasing the many upgrades in the old building below to make it ready for Ontario’s double cohort of admission students in September.

Jantzi explains that they are achieving energy savings by the use of heat recovery units for areas like the metal workshops and jewelry studios that require 100% outdoor air. They have also added a new central direct digital control building automation system, and overall the building will conform to the ASHRAE 90.1 energy standards.

Going against the tide

While the Canadian engineers have enjoyed working with international architects, how did the experience seem from the other side? Isabel Brebbia of Alsop’s studio, for example, spent months in Toronto working on the project with architect Gregg Woods and others at Robbie, Young and Wright.

She praises the work of the Canadian engineers, but has some misgivings about the Canadian construction industry. “We’re used to working more with an environmental slant,” she says. “The environment didn’t seem to be in the forefront of people’s minds.”

Brebbia also got the impression that engineers and architects don’t collaborate as closely as in the U.K. “The thing that we found different in Canada,” she says, “was that the consultants tended to wait a bit until the design had settled down. They didn’t do as much front end work as we’re used to, which was a bit frustrating.” She adds, “presumably it is so that when a design changes you haven’t wasted time engineering something.”

Brebbia also found that the palette of materials is more restrictive on this side of the Atlantic. Just as Lib
eskind had to switch from the pure glass skin to something more practical to suit the Canadian climate and economy, so the Alsop team had to adapt and temper their original grand vision. They wanted the flying rectangle’s underside to glow at night, backlit through a polycarbonate panel, but the U.K. materials aren’t approved by Canadian building codes. Similarly, their choice of cladding was thwarted. They had wanted a kind of iridescent, duotone aluminum that would subtly change colour with the shifting light, but no manufacturer would take the risk on the unfamiliar material. The black and white checkered cladding replacement will make the tabletop appear more solid than in the original design.

Alsop’s team would have liked to use energy strategies advocated by environmentalists such as displacement ventilation and a double wall. Budgets didn’t allow it. They wanted the building’s legs to be thinner, and the support core to be narrower.

Despite their compromises, Brebbia is happy that their original architectural concepts have survived relatively unscathed. “In balance the end result is pretty close — certainly with the legs themselves,” she says.

It’s not surprising that the U.K. architects found it difficult to swim against the strong tide of convention in Canada. Our construction industry is conservative because economics play such a driving role. The clients in both Toronto projects have received big grants from government, but not enough to meet their costs. Indeed, several of the designers interviewed said that the owners are the true heroes in these projects because they dared to sponsor such eccentric, jaw-dropping structures in the first place.

The Ontario College of Art addition opens in the spring, and the ROM’s crystal is scheduled for completion in 2006. The engineers will probably fall below the radar screen in the great hubbub of celebration and cork-popping that will attend the opening events. As the debates rage over the architecture and its impact on the city, no-one will remember the hard slog of calculations, measurements, the wearying meetings and to-and-fro debates between the different design disciplines that went on behind the scenes. But it is thanks to the unseen work of engineers, their practical mindset and careful diligence — and, yes, thanks to their cautionary approach — that these buildings are able to exist at all.


Royal Ontario Museum Michael A. Lee-Chin Crystal

Structural: Arup Canada/Halsall Associates (Neb Erakovic, P.Eng., Shah Sagharian, P.Eng., Mike Jordan, P.Eng., Matt Humphries, Ken Sissakis, Nick Michisor, Ian Trudeau)

Mechanical: Arup Canada (Julian Sutherland, P.E.)/ The Mitchell Partnership (Jim Ovens, P.Eng., David Blenman, Robert Shute, P.Eng.)

Electrical: Arup Canada (Daniel Brace)/ Mulvey + Banani (Diego Battiston, Jerry Mobilio, Ismail Bhabha, Mike Hamza, P.Eng., Regina Brozyna)

Architects: Studio Daniel Libeskind/Bregman + Hamann

Construction: Vanbots

Steel fabricator: Walters

Ontario College of Art & Design

Sharp Centre for Design

Structural: Carruthers & Wallace (Chris Andrews, P.Eng., Paul Sandford, P.Eng., Li Ming Tang, P.Eng., Sha Zhu)

Mechanical & electrical: MCW Consultants (David Hillyar, John Sloan, Tim Jantzi, P.Eng.)

Wind studies: Univ. of Western Ontario Boundary Layer Wind Tunnel Laboratory

Architects: Alsop/Robbie, Young + Wright

Project Management: PHA

Construction: PCL

Steel fabricator: Walters

Geotechnical: Shaheen & Peaker


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