Interior structure, exterior detailing combine to deliver strong visual presentation

The Trio project consists of three apartment buildings with a shared above-ground parking garage in Kitchener, ON. Building A is a total precast concrete structure, as are Buildings B and C, which are under construction.

By Andrew Bousfield

Building A was among the first total precast concrete residential apartment towers designed by our firm, ABA Architects, to feature a perimeter bearing alignment [structural walls aligned parallel to the length of the building slab, exterior walls and one corridor wall]. Prior total precast concrete apartment buildings designed by ABA utilized a shear wall bearing alignment [structural walls running perpendicular to the length of the building slab]. 

As the long perimeter walls of the slab are load-bearing, there are limitations on how many openings for windows, louvres, and vents can be available. ABA worked very closely with the precast manufacturer to optimize the size and number of windows around the building’s four sides. A perimeter bearing scenario also presents some challenges with structured underground parking, as the internal corridor bearing line usually runs right through the middle of the drive aisle. ABA and the client, HIP Developments Inc., worked around this by designing and constructing a separate total precast concrete above grade parking structure to serve all of the Trio buildings.

HIP Developments Inc. was looking for an iconic architectural expression for the three-tower project and one that would be identifiable and distinctive on the Kitchener skyline. Our firm also appreciated that Trio would be the first of many subsequent residential designs in total precast concrete utilizing a similar bearing alignment, and so it was paramount that this first effort pushed the envelope of the structural system such that the client could come to understand its limitations and benefits.

We did not want the buildings to read as singular slabs of repeated floor plates superimposed on each other. We were also interested in bringing maximum daylighting into the suites, and this led to the implementation of the “staggered balconies”; where balconies were offset one on top of the other such that each balcony enjoyed two floor levels of height before the underside of the next balcony above it. This lends the Trio balconies an uncommon feeling of space and also allows daylight to penetrate much deeper into the suites than a configuration where balconies overhang windows immediately above one another.

The staggered balconies also allowed for the most recognizable architectural feature on the building: the “white boxes”, which frame many of the double-height balconies and break up the facade into discreet elements that alter perceptions to the scale of the building facades. The boxes are also precast concrete, which arrived on site as four pieces to be assembled during installation.

The dark colour palette of the precast concrete exterior wall panels, consisting of colour gradients of grey, contrast sharply with the stark white colouring of the boxes to give the building a strong visual presentation.

Andrew Bousfield is a principal with ABA Architects, Inc. in Waterloo, ON. 

Construction 
By Kurt Ruhland

Speed was the defining characteristic of a very efficient construction process. Precast concrete supplier, Coreslab Structures, began installation in March, 2016, and was installing the 10th floor by the first week of June, taking a week on aver- age to install one level of floor and walls. In addition, using set precast concrete sizes allowed for immediate installation of windows and the ability to begin finishing the interior of each floor level as construction continued.

The 14-storey Building A uses 1,290 pieces of precast concrete consisting of: 48 columns, 172 balconies, over 1,000 wall panels, 16,908 square metres [182,000 square feet] of hollow core floors, and 54 stairs and landings. The heaviest precast concrete pieces are found in the balconies, each having and area of 15 square metres [164 square feet] with a weight of 50,706 kilograms [23,000 pounds].

Precast concrete wall panels are either 200 or 250 millimetres [8” or 10”] thick and stained in the field using the desired colours. The average floor area is 1,224 square metres [13,180 square feet]. Buildings B and C have a similar structure as Building A, using 1,100 and 860 pieces, respectively, of precast concrete.

The above ground precast concrete parking garage uses a fairly typical double tee floor system with structural beams, columns, column walls and shear walls. The 49 spandrels used were field stained by Nawkaw. The parking decks are finished with a concrete topping.

Photos: HIP Developments Inc.  
Kurt Ruhland is a Director with MTE Consultants. Inc.