ATI TECHNOLOGIES INC.

Developer: Metrus Developments
Architect: Page + Steele Architects Planners

This suburban corporate office complex, located in Richmond Hill, Ontario, was completed in 2001.

It is a four storey reinforced concrete structure, constructed over two subgrade vehicular parking levels.

The structure is founded on reinforced concrete caissons and grade beams. Caissons are founded in natural silty clay tills capable of safely sustaining pressures of 1500 kilopascals and 2400 kilopascals, (ie. 31,320 pounds, 15.66 tons per square foot and 50,112 pounds, 25.01 tons per square foot) depending upon the location on the site.

The P-2 parking level is a 100 mm thick concrete slab-on-grade with fibrillated polypropylene fibers. The P-1 parking level is a reinforced concrete flat slab with a thickness of 240 mm, and 150 mm deep drop panels, in the areas below the superstructure, where the bays are nine metres square. Beyond the limits of the superstructure, where the spans are in the range of six to seven metres, the flat slab thickness is 210 mm, with 100 mm deep drop panels.

The ground floor area, within the limits of the superstructure, is a 270 mm thick reinforced concrete flat slab, with 150 mm deep drop panels, and 300 mm deep capitals, designed to carry loads up to 4.8 kilonewtons per square metre. Beyond the limits of the superstructure, the framing is a 300 mm thick reinforced concrete flat slab, with 150 mm deep drop panels, and 300 mm deep capitals, designed to carry loads up to 12.0 kilonewtons per square metre.

The second, third, and fourth floors are similar and were designed to carry loads up to 2.4 kilonewtons per square metre. These floors are typically 220 mm thick reinforced concrete flat slabs, with 200 mm deep drop panels. Reinforced concrete beams were provided at outer bays to achieve the rotational offsets of the ascending floors. All of the floors, above the ground floor, feature a central six bay open atrium space, which is covered by a high roof level skylight between mechanical penthouse roofs.

The roof slab is also typically a 220 mm thick reinforced concrete flat slab, with 200 mm deep drop panels, and beams, in the outer bays. The mechanical penthouses’ slabs are 320 mm thick, with 200 mm deep drops.

The roofs of the mechanical penthouses are framed as a series of 150 mm and 180 mm thick one-way reinforced concrete slabs, supported on reinforced concrete beams. The skylight, between the roofs of the mechanical penthouses is supported on a series of five 840 mm deep, and two 760 mm deep structural steel beams.

FILMPORT – PHASE I COMPLEX

Developer: Toronto Film Studios Inc. | Architect: Quadrangle Architects Limited

The project site, on the south side of Commissioners Street, at the east side of the Don Roadway, borders on a shipping channel of Lake Ontario, and has been planned to accommodate more than thirty sound stages.

The structural steel superstructure of each building is somewhat different, however, the stages all have long spans ranging from 23.7 metres to 56.3 metres.  The one thing that they all have in common is the ground floor slabs.  To overcome the very poor soil conditions, the ground floor slabs were all designed and constructed as 250 mm thick flat slabs with 250 mm deep drop panels designed to sustain a live load of 12 kilonewtons per square metre (250 pounds per square foot).  The bay sizes for the flat slabs, at the ground level, are in the range of 6.5 to 7.5 metres, with the drop panels, supported on structural steel “H” piles, which were driven to refusal into shale bedrock.

The shop buildings 8A & 8B have flat roofs with 38 mm deep by 0.76 mm steel deck, supported on, 900 mm deep, long span steel joists.  To attenuate exterior sounds, the roof of the stages have 100 mm of concrete over 50 mm deep composite steel deck resulting in a total concrete thickness of 150 mm.  With the exception of stage 4, the roofs are basically flat with the concrete decks being supported on, 2400 mm deep, long span steel joists, spaced at approximately 1.91 metres centre-to-centre.

All of the buildings’ columns are supported on caissons and/or structural steel “H” piles, socketed or driven to refusal into shale bedrock.  Stage 4 is unique in that, the special buttresses employed to provide lateral resistance and support the barrel arched beams (trusses) of the roof had, in most instances, to be tied down with two, 46 mm diameter Dywidag rock anchors, grouted into the shale bedrock and stressed to a working load of 1000 kilonewtons (225,000 pounds).

In addition to the unique buttresses, supported on reinforced concrete plinths, bearing on caisson caps the roof with a clear span of 56.3 metres is worthy of note.  The arched beams, support, typically 460 mm deep, structural steel wide flange beams at 6.095 metres centre-to-centre, which in turn support 400 mm deep open web steel joist at 1.6 metres centre-to-centre, curved in the vertical plane to create the circular profile of the framing and support the 150 mm thick concrete and composite steel deck roof.

In order to provide the necessary noise attenuation, and to present a uniform appearance, all of the sound stages are clad with textured precast concrete panels supported on perimeter reinforced concrete grade beams spanning between caissons.

THE MANULIFE CENTRE-TORONTO

 DEVELOPER: THE MANUFACTURERS LIFE REALTY LIMITED
ARCHITECT: CLIFFORD & LAURIE ARCHITECTS

This was one of the first multi use complexes built in downtown Toronto, combining a fifty-one storey residential tower, and a nineteen storey office block, over a three level shopping centre, with a three level subgrade parking garage underlying the entire complex.

The residential tower is the tallest reinforced concrete apartment building in Canada, and employs reinforced semi-lightweight concrete slabs and reinforced concrete shear walls. The walls are founded on individual footings bearing on 12 ton soil. Welded wire mats were used as the main slab reinforcing.

To achieve the splayed out expression of the office block floors, from the third to the fifth floor level, a bonded post-tensioned system was employed.

All of the superstructures are clad in precast panels with glazing in aluminum frames. To reduce the time of the working cycle, on a floor of the residential tower, from five to three days, such items as precast stairwells, colour-coded wire fabric reinforcing mats and preglazed precast wall panels were shipped to the site ready for installation. These innovations along with the use of two and one-half cubic yard magnesium buckets for placing the semilightweight concrete enabled the structure to be completed in record time. 

ONE ST. THOMAS RESIDENCES

Developer: Lee Developments
Architect: Robert A. M. Stern Architects • Yonge + Wright Architects Inc.

This thirty-one storey ultra high end residential condominium project, also includes four high end townhouses, each with its own private elevator. It is located close to the trendy part of Bloor Street in downtown Toronto.

The structure is carried on walls and columns founded on strip and spread footings, respectively, bearing on natural undisturbed soil, capable of safely sustaining a pressure of 750 kilonewtons, (ie. 15,660 pounds or 7.83 tons per square foot).

The subgrade parking level slabs are typically 200 mm, or 220 mm, thick, to satisfy the spans, reinforced concrete flat slabs with 125 mm deep drop panels over the columns. At the east portion of the P1 parking level, there is an exception where the reinforced concrete flat plate is a 550 mm reinforced concrete transfer slab on 400 mm deep capitals designed to carry the party walls of the four townhouses above.

The ground floor framing incorporates a wide variety of reinforced concrete slabs and beams, to satisfy different loading requirements and spans. There are seventy-nine beams in the ground floor framing, many of which are transfer beams with depths ranging from 1100 mm to 1800 mm.

The floor slabs, from the twelfth floor level, up to the eighteenth floor level, are similar, 220 mm thick reinforced concrete flat plates, as in the levels below. Above the eighteenth floor slab level, the core is reduced, with the new configuration being maintained up to the twenty-first floor level, where it is further reduced up to the twenty-eighth level, where a private internal suite elevator is introduced between the twenty-eighth and twenty-ninth floor levels. All of the floor slabs from the nineteenth level through to the twenty-ninth level are 220 mm reinforced concrete flat plates similar to the floor slabs below the eleventh floor level.

The thirtieth floor slab level is a series of one-way reinforced, concrete
slabs, with thicknesses ranging from 200 mm to 275 mm, to support the
loading of the elevator machine room and the mechanical equipment,
and to provide slopes to the roof drains, north and south of the
mechanical penthouse.

Lateral forces resulting from wind or seismic effects are resisted by the central core which encompasses elevator shafts, a scissor stair and mechanical shafts. Below the eleventh floor, two shear walls are added to the lateral forces resisting system.

The concrete strength at twenty-eight days for the walls and columns was specified to be 45 megapascals below the seventh floor, and was reduced in 5 megapascal increments down to 30 megapascals above the
eighteenth floor.

33 & 55 HARBOUR SQUARE CONDOMINIUMS TORONTO

Developer: The Campeau Corporation
Architect: Bregman Hamann Architects

The first and second phases were constructed between 1970 and 1977. The cranked shapes of the plans of the two towers at the edge of Lake Ontario presented a special wind analysis problem, which had to be solved, before the reinforced concrete slabs and shear walls of the structural could be designed.

To minimize the shrinkage deformations of 450 feet long floor plates, the structure was separated by a temporary vertical contraction joint, located in the centre of the structure.

The temporary contraction joint was connected after the structure was enclosed and heated.

The lateral wind forces of the open lake exposure were sustained by employing concrete shear walls concentrated into four clusters of rigidity, which were investigated by employing a three-dimensional computer model. 

Reinforced concrete caissons, with permanent steel liners socketed into bedrock, below the surface level of the lake, had to be installed to support the apartment building.

The multi leveled parking garage between the two residential towers incorporated the first use of deep modified drop panels, to support large areas of a structure, in the Toronto area.

BANKERS HALL PHASE II

Developer: Trizec Hahn Office Properties
Architect: The Cohos Evamy Partners Architects

After the success of Phase I, which included the east office tower, and a six storey podium, which was designed to support a second high rise office tower, the Owner decided in 1997 to construct the second phase west tower of the Bankers Hall project.

Structural steel grillages were erected, at the sixth level roof, of the podium, to support two climbing cranes, that would be employed to construct the second office tower, and to initially transfer the loads imposed by these cranes to the existing building columns below.

At the top of the sixth level framing, vertical reinforcing steel bars projected above the top surface of the structure, to enable mechanical splices to be employed to connect the next tier of vertical reinforcing steel in the walls and columns from the sixth to the seventh floors.

The same framing system was employed for the floors of the west tower, as had been proven to work so efficiently in the east tower. The system employed, haunched reinforced concrete girders, typically, at nine metres on centre, spanning twelve metres from the perimeter columns to the central core. Between the perimeter reinforced concrete spandrel beams and the central reinforced concrete core, there are two parallel lines of reinforced concrete purlins, spanning between the haunched beams, which support the 130 mm thick one-way reinforced concrete floor slabs.

Above the fiftieth floor, which is the mechanical level, the sloping roof, which extends up to a concrete ring beam, above the fifty-second level, is framed in structural steel, and encloses the four cooling towers with a special metal roof cladding system. Inside of the structural steel roof enclosure, concrete columns extend up to support mechanical mezzanines at the fifty-first and fifty-second levels and the reinforced concrete ring beam above same.

To satisfy the loads in the columns, being brought to bear by fifty-two levels of reinforced concrete framing, the concrete strengths in the columns ranged from 80 megapascals at 120 days below the thirty-third level, to 65 megapascals at 120 days from the thirty-third to the thirty-sixth level, to 50 megapascals at 120 days from the thirty-seventh to the thirty-ninth levels and so on down to 30 megapascals at 28 days above the forty-third level.

Wind affects are the controlling lateral forces, acting on the structure, and are resisted entirely by the central core, in the north-south direction. However, in the east-west direction, the lateral wind forces are resisted by the interaction of the frames, comprised of the spandrel beams, and close spaced columns, on the north and south elevations, with the central core.

ATRIUM ON BAY MEDIA TOWER

Developer: Trizec Equities Corporation
Architect: Bregman + Hamann Architects

This is the first of the electronic billboard structures to be constructed at the intersection of Yonge and Dundas Streets in downtown Toronto,

It was erected over a portion of the existing Atrium On Bay, a mixed use development, above the roof of the reinforced concrete retail structure at 306 Yonge Street.

The tower is basically a series of five, six metres wide, transverse, vertical trusses, extending up, from twelve to fourteen levels, above the roof of the existing base retail structure. The vertical trusses are spaced at six metres center-to-center and are interconnected by walkways, at each end of the trusses. The walkways are located at three metre vertical intervals and are connected by steel stairs at the west end of the tower.

The walkways are individually braced and the entire series of trusses are braced horizontally, at levels 117.05 m, 129.05 m, and 141.05 m, ie. at twelve metres vertically on center. There is also vertical cross bracing, at the north and south ends of the trusses, with the double angle diagonals connected to the truss nodes at six metres vertically on center.

Typically, there are W200x36 horizontal structural steel girts on the north and south faces at one and one-half metres vertical centers. These girts have 9/16″ diameter openings at 450 mm centers pre-drilled, in the outer flanges, and 13/16″ diameter openings at 900 mm centers, at the center of the webs to accommodate future signage connections.

All of the structural steel conforms to CSA Standard G40.21-350W. All of the structural steel work is protected with special corrosion inhibiting coatings specified by the Architect.

FAIRVIEW SHOPPING CENTRE – POINTE CLAIRE-QUEBEC

Developer: The Cadillac Fairview Corporation Limited
Architect: Architects Crang and Boake Inc.

The original centre, the structure of which was designed by this office, was built in 1964, and served the region from west Montreal to Cornwall so successfully that it was decided to add a second level in 1981. The primary criterion was that the existing shopping centre be kept in operation throughout the construction period.

In order to expand the original structural steel frame vertically. without removing the original roof framing, the columns were strengthened and extended vertically to support the new second floor level steel frame, and the new roof steel framing above the new second floor level. The new trusses spanning across the central mall were left exposed as part of the architectural expression, which included a linear skylight between the two anchor department stores.

All of the structural work was completed above the original roof level, to cause as little disturbance as possible to the operation of the centre. The strengthening of the original columns, and the foundations supporting same, was done for the most part after business hours, so as to cause minimal disturbance to the merchants.

After most of the construction work, on the new upper level, was completed, the original roof framing, in the mall, was removed to open the mall space to the new skylight and roofs above.

To minimize the impact upon the merchants special underpinning and strengthening methods were developed to satisfy both the needs of the merchants, and the contractor.

In addition to the business operation having to be maintained, all of the service systems were to be kept operational during the construction period. Therefore, the structural design also had to be coordinated and phased with the operations and retrofitting of the mechanical and electrical systems.

POLO PARK SHOPPING CENTRE WINNIPEG

Developer: The Cadillac Fairview Corporation Limited
Architect: Architects, Crang and Boake Inc.

With the successful completion of the Pointe Claire Centre, the developer decided upon a vertical expansion for the Polo Park Shopping Centre, in Winnipeg. Here too, the primary criterion was to keep the centre in operation throughout the construction period, of the vertical expansion.

Special designs and procedures were developed to perform the strengthening of the existing structural steel frame, to cause the minimum inconvenience to the merchants. Similarly, extra ordinary designs and techniques were employed to install new caissons, and grade beams, where foundation strengthening was also required. 

As at Pointe Claire, the second level and new roof framing was erected above the original roof level with most of the construction on the upper level being completed, before the original mall roof was opened to expose the new mall level, and skylights, above.

In addition to the vertical expansion of the centre, the project also involved the design and construction of a precast concrete parkade deck, above the existing parking lot required to increase the capacity of the customer parking. This also involved pedestrian bridges to permit customers to enter the upper mall level, directly from the parkade deck.

RADISSON HOTEL – LONDON

Developer: Commonwealth Hospitality Limited
Architect: Bregman Hamann Architects

The hotel was built in 1972 and 1973 and was originally the Downtown London Holiday Inn.

As part of the London City Centre Project it is a reinforced concrete structure constructed over a two level subgrade parking garage.

The difficult soil conditions and the high ground water table combined to present some special foundation dewatering and construction problems all of which had to be considered in the initial structural design stages.