Council on Tall Buildings and Urban Habitat
 

Absolute World Towers, Mississauga
Featured February 2013

Absolute World Towers were originally featured as a case study in CTBUH Journal 2012 Issue IV, available as a PDF download. Absolute World Towers was recognized as the "Best Tall Building Americas" in the 2012 CTBUH Awards Program.

Other Featured Tall Buildings

“The Absolute Towers stretch the limits of paired sculptural form to create a marker on the skyline for a regional center.”
- Richard Cook, CTBUH 2012 Awards Chair, Cook+Fox Architects 

Location
Mississauga
Completion
2012
Height
158 meter (518 ft)
Stories
50
Primary Use
Residential


Owner/Developer
Fernbrook Homes

Cityzen Development Group
Design Architect
MAD

Associate Architect
Burka Architects
Structural Engineer
Sigmund Soudack & Associates Inc.
MEP
Stantec
Project Manager
MAD
Contractor
Dominus Construction Group

Absolute Towers is a striking example of a private/public approach to development in a city that was perhaps unaware of the extent an architectural design could impart conversation, energy, and vitality into the community. The towers definitively stand out on the skyline of Mississauga, bringing distinction to the little-known, but fast-growing, suburb of Toronto.

These towers have a sense of motion that brings a smile to the face. The torsional form of the towers evokes a natural, human feel to the buildings, and it is perhaps not surprising that the buildings have picked up the local nickname, Marilyn Monroe, with the curvaceous, sexy form an obvious association. Their effortless connection to the surrounding natural landscape creates a sense of unity while also putting forth an icon. To see such a dramatic form achieved with a simple, rational structural solution is refreshing.

Figure 1 .Overall view in context from northwest

Mississauga, a suburb of Toronto, is like many fringe towns in that it is growing in relation to its neighboring metropolitan area, though it does not have any architectural precedents for this growth. At around 734,000 residents, the city is in demand of residential property. To win the first international design competition held in the Toronto area in over 40 years, the architect put forth a radical design for a curving and biologically inspired design. When the tower project was proposed to the public, initially with only one tower, the scheme was so popular that the units sold out just days after the release of the building plans. After this response, the owner decided to buy an adjacent plot and build a second tower to meet the demand.

While the typology of the skyscraper, typically a glass box, is usually associated with a large city, many suburban areas are now experiencing expansion which requires the implementation of high-rise buildings. As a bold step in this initial direction, the Absolute World Towers are the tallest additions to Mississauga’s predominantly low-rise urban fabric; they are two of only six towers over 100 meters in the area, standing out as an organic and recognizable gesture along the skyline.

Figure 2. Overall view from north
The redevelopment of a major downtown intersection was seen as an opportunity to redefine Mississauga’s urban landscape through an innovative public-private partnership and internationally recognized architectural design. The project had to add something naturalistic and human to contrast with the existing backdrop of listless boxy buildings.

The winning design obeys many of the rules of the typical North-American high-rise: a central core, a straightforward and economic structure and a glass façade. However, the outcome is fundamentally different in the perception of the people. By the time of completion the result was recognized by the public and news accounts as an inspiring place to live, something more than a place that strives for simple efficiency. The buildings hope to provide residents with an emotional connection to their hometown and neighbors, and a local landmark to define the city.

Figure 3. Close up view showing cantilevered balconies

Figure 4. Façade view looking up
A Risky Development Plan
The developers of the site, Fernbrook Homes and Cityzen Development Group, were determined to tackle the lack of a unique character when they set out to redevelop the intersection in Mississauga’s downtown core. It was determined that the best use for this important property would be a residential development. The entire project includes a master-planned community of five towers with more than 158,000 square meters, 1,850 residential units, a three-story 3,252-square meter recreation area, and retail facilities.

In a break from industry tradition, Fernbrook and Cityzen sponsored an international competition to find an iconic design that would realize their vision. This was the first such design competition that the GTA had seen in more than 40 years and the Mayor and City embraced the opportunity with great enthusiasm.
Due to the prominence of the location, the City had a special interest in the redevelopment initiative. They were an active partner in shaping and realizing the development vision. In a unique spirit of partnership, the City was invited to participate on the judging panel for the project. The City and its residents were part of the decision-making process and helped identify the winning proposal. The City also worked closely with the developer throughout the construction process to manage many of the unique challenges associated with implementing the unprecedented features of the successful design. The public sense of ownership that defined this undertaking from its inception helped bring the project to realization.
Figure 5. Child's drawing of Absolute World Towers
The response to the competition far exceeded expectations. More than 600 expressions of interest were registered and 92 submissions received, producing an array of unique and inspiring architectural designs from a global pool of talent. The winning design from Ma Yansong of MAD Architects clearly captured the public’s imagination. MAD’s design stood out for its ability to offer a sharp contrast to the existing landscape of traditional rectangular buildings that had come to define Mississauga.
A Distinct Shape
Winning the competition generated enormous public interest internationally, but was particularly noteworthy in China, where MAD became the first Chinese architecture office to build a significant high-rise project abroad. Suddenly a young architect from mainland China was given an international platform to showcase new ideas and design philosophy. This also offered Chinese developers a new appreciation for the potential of their domestic talent.
Fondly dubbed the “Marilyn” by local residents in homage to the curvaceous appeal of Marilyn Monroe, the Absolute World Towers parallel the twisting fluidity of natural lines found in life. The flowing form offers an organic punctuation in the landscape and challenges the prevalence of commonplace development in the area.

The design brief presented for the competition – calling for a single tower – was straightforward, with restrictions limited only to the amount and size of units. This allowed the competing designers full expression and flexibility.

Eschewing the tradition of accentuated verticality in high-rises, MAD’s design for the Absolute World Towers chose not to emphasize vertical lines. Instead, the design features smooth, unbroken balconies that wrap each floor of the building. In addition, at each successive level, the floor plate rotates in a range of one to eight degrees affording panoramas of the Mississauga skyline. By maximizing the viewing potentials both inside and outside the buildings, the design created a medium for social interaction throughout the balconies and connected the city dwellers with naturalistic design principles.
Figure 6. The continuous wrapping balconies
Building an Idea
Many observers questioned whether the MAD design could actually be built. The unique features of this type of rotating structure had never before been subjected to Ontario building code requirements and there was no precedent for the construction challenges.

From the outset, local architectural and engineering firms were engaged to refine the design and ensure it would meet all local standards without compromising the initial design intent. While the lead time for most projects was normally three to four months before excavation was scheduled to commence, in the case of Absolute World, the preparatory period was extended to 12 months.

While consultants always play a major role in the construction of any project, in this case their role was even more significant. The rotating design meant that every floor was unique. Meeting these challenges required extensive collaboration among all the construction disciplines throughout the process.

In addition, there was some initial concern that the unique layouts would limit the ability to market and sell residential units in the tower. However, the interest generated by the competition and the public’s participation in the final selection helped the developers easily sell out the apartments in a few days. The developer had taken a significant gamble in committing to deliver a design developed out of a competition, but the results provided evidence that design does matter in the marketplace and a unique design can sell at a premium.

Given the initial response, the developer requested that the architect produce a design for a second tower. Ma Yansong was adamant that a second tower should be complimentary, but not a duplicate of the first tower. The second building’s design used the same technique of rotating floor plates, but featured different angles to create a different, but related form.

Figure 7. Typical floor plan
The first and tallest tower starts to twist from below and increases its rotation initially by 1 degree to a maximum of 8 degrees rotation per floor for a total cumulative floor plate rotation of 209 degrees. The building’s vertical middle section, or its “hip,” represents the maximum eight degree rotation. For the second tower, the rotation was 4 degrees for every floor for a total cumulative floor plate rotation of 200 degrees.

The addition of a second building actually strengthened the original concept. As the architect observed, a single tower could have been viewed as a sculptural piece, but the addition of a second tower transformed the development into a true urban space.
An Economy of Structure
The torsional form of the towers is underpinned with a surprisingly simple and inexpensive structural solution. The two residential towers are supported by a grid of concrete load-bearing walls. The bearing walls extend and contract in response to the sectional fluctuation created by the rotation of the floors, while the balconies consist of cantilevered concrete slabs. In order to ensure the elegant edge profiles are as thin as possible, there is a thermal break in the slabs at the exterior glazing, so that the insulation need not wrap the entirety of the balconies. Meanwhile, the dynamically fluid shaping of the towers, naturally aerodynamic, adeptly handles wind loading and ensures comfort throughout all the balconies. In addition to providing every resident with a livable exterior place to enjoy views of Mississauga, the balconies also naturally shade the interior from the higher angle summer sun while soaking in the lower angle winter sun, reducing air conditioning costs.
A key feature of the buildings‘ design is the presence of continuous wrapping balconies on every floor. The balconies are also an integrated part of the curved and rotating design of the overall structure. This groundbreaking design presented unique challenges relating to the transfer of cold and heat, both horizontally and vertically. While balconies can create thermal challenges in traditionally shaped structures, in the Absolute World the curved and rotating design of the building compounded the challenges.
Figure 8. Typical balcony configuration
The horizontal thermal transfer concerns required a break in the concrete slabs that would still accommodate the unique design features. The rotating floor plates also caused additional vertical thermal transfer issues. As the floor plates rotated, the window lines did not align as in traditional building structures and this created another set of transfer issues.
A number of potential solutions were considered but dismissed for being excessively costly or risking construction delays. The team was also not prepared to consider a solution that would compromise the balcony feature for any of the suites.

The solution was eventually found in an innovative two-pronged approach: thermal breaks were utilized to minimize the horizontal thermal transfer, and an internal bulkhead, along with an external insulated soffit, was utilized to minimize the vertical thermal transfer. The thermal breaks were formed in such a way that it allowed for sections in the slab up to 50 millimeters in width and varying lengths up to 1,200 millimeters. The void that resulted from this approach was later finished with fire stopping, smoke seal and waterproofing.

The unique design properties of the building also required an innovative concrete forming method. Traditional fly tables were not appropriate for this construction because they would have resulted in large unsupported panels when the rotation of the floor plate was more than two degrees. The formwork partner, Premform, needed to develop a new forming method that would allow for configuration changes, while maintaining structural integrity. This had to be accomplished without compromising safety.

Premform’s solution teamed two main features – an EFCO climbing elevator formwork system and a modified Peri’s SKYDECK drop head system with a modified rail climbing system (RCS). The climbing elevator formwork system contributed to project efficiency and allowed for faster turnaround on the main central core of the building, avoiding schedule delays. The modified SKYDECK provided the ability to form the constantly changing floor plate by allowing panels to be carried out immediately after the slab concrete reached the required strength. This revolving process permitted panels to be used immediately for the next cycle. Through these innovations, the construction team was able to achieve a cycle time from floor to floor that could match those of traditional systems for conventional building designs.
Figure 9. Structural Diagram
Concrete Considerations
The last major innovation in the construction of this building related to the use of the concrete. Although the building was unique in its design, it was still required to meet all structural requirements for a residential condominium, creating another set of challenges.
First, the traditional concentric loading of columns was not appropriate for the unique design of the building. The structural engineer, Sigmund Soudack and Associates, was presented with the challenge of finding an alternative that utilized sufficient rebar and concrete while still allowing for livable spaces. The final structural design included heavy reinforcement at the bottom of the tower using 35M bars. However, this design did not allow for use of traditional methods to consolidate the concrete. The final concrete specification called for 70 Mpa columns, walls and beams; and 50 Mpa slabs.
Figure 10. Rail climbing system (RCS)
While this addressed some of the structural concerns, the concrete was still required to meet functionality considerations and ensure formability and final finish of the flooring. This represented the second major challenge. The concrete supplier, Innocon, had to identify a product that could meet the need for high volume, accurate consistency,  accommodation of a tight construction schedule, reliability in a full cycle of seasons, and functional workability on floor slabs. The concrete supplier recommended the use of self-consolidating concrete. This product was capable of meeting all the requirements for the columns and walls and could be used in a special mix for the slabs. The product also offered the added benefit of increased efficiency by requiring fewer workers and minimizing the risk of worker crowding. The construction schedule spanned over a full cycle of seasons and special methods were utilized to ensure sufficient heating in the winter and cooling in the summer to allow the concrete to properly cure.
Figure 11. SKYDECK slab formwork Figure 12. Heavy structural reinforcement at tower base

A New Urbanism
The end result of the process created a new form of urbanism based on partnership and innovation. All aspects of the Absolute World Towers project challenged the boundaries of conventional industry norms and practices. The initial design competition allowed dynamic new ideas and design philosophies to come forward. The engagement of the City contributed to shaping and realizing the development’s vision, consistent with the City’s own aspirations. The resulting architectural design broke free from conventional thinking and introduced a natural form back into the city’s (sub)urban experience, made possible by a series of design and construction innovations. The result is a distinct type of urbanism and a curvy new shape for future cities.

Figure 13. Absolute Towers create a stunning contrast with the surrounding boxes
At the forefront of a movement among tall building designers to rely on biomimicry, the buildings are spearheading organic form and a connection to nature. While other building designs have created complex curvilinear geometries, the Absolute Towers accomplish it with a straightforward concept and structural solution. In light of the commercial and critical success of the flowing towers, upcoming building projects may take inspiration from this simple and grounded approach to accomplish their goals.

As Mississauga continues to grow, future projects can rely on the precedent set by the towers in both their concept and execution. Eventually, the buildings will become part of a more dense urban setting, but will still have a unique effect on their surroundings.

Related Links
CTBUH Skyscraper Center Profile:
Absolute World Towers

Absolute World Towers was recognized as the Best Tall Building Americas Award Winner in the 2012 CTBUH Awards Program.
Download Absolute World Towers 2012 CTBUH Awards Book section

2012 CTBUH Awards Book

CTBUH Journal 2012 Issue IV:
Download the Paper

The CTBUH would like to thank MAD Architects and Dominus Construction Group for their assistance with this article.
Photography © Tom Arban, MAD Architects, PERI and Dominus