Ontario Court of Justice

Toronto

facade design, special structures Services

Renzo Piano Building Workshop Architect

A courthouse that combines transparent architecture with high security requirements

Project

The Ontario Court of Justice building combines various courts in one building in the heart of Toronto. It consists of two main elements: a four-storey podium with a 20-metre high, highly transparent atrium and a 13-storey tower rising above it. From the outside, the tower and podium are separated by a cantilevered canopy and a recess in the façade. This separation is made clear in the building envelope, which covers a total area of 15,520 m², by three different types of façade: the podium and the atrium are surrounded by a transparent mullion and transom façade and a double-layered cable construction. The main façade of the tower is designed as a glazed element façade with three-dimensionally shaped steel sheets.

Hydroformed steel sheets give the façade depth and create micro-shading on its surface

Tower Façade Construction

The tower façade, designed as a unitized façade, consists of transparent insulating glazing and opaque shadow box panels. The division into four differently sized areas creates a pattern that lends the massive building volume a delicate, small-scale appearance. The glazed areas allow views of downtown Toronto and create light-flooded interior spaces. The opaque insulation panels are clad with glazing on the outside to ensure a uniform appearance. Inside, the insulation panels are clad in hydroformed steel sheet, whose undulating geometry creates dynamic depth and micro-shading on the surface of the façade.

One particular challenge was to combine highest safety requirements with maximum transparency in the double-cable façade.

Cable Façade Construction

The cable façade of the atrium is designed as a two-layer construction consisting of vertical pre-stressed cables on the inside and outside, as well as steel T-profiles tensioned between them on the inside and outside. The highly transparent glazing is mounted linearly on the horizontal steel profiles and is additionally supported at mid-height by a local clamp. In the design development, the main focus was on the creation of filigree connection details - from milled cable clamps and recessed connecting plates for the steel profiles to the thermally separated couplings of the inner and outer supporting structure: the intensive development work on the design details made it possible to combine the highest safety requirements with a filigree appearance.

The iconic mast spans approx. 85 m high in front of the tower façade

Structural Analysis of Mast Feature

The structural development of the approx. 85 m high mast, which spans freely in front of the glass façade of the high-rise building as an iconic object, posed a particular challenge. Triangular steel brackets are used for horizontal load transfer, to which diagonal cables are connected, which transfer the weight of the structure. Attention was paid to the filigree detailing, in which the structure is connected to the structural floor slab by means of a flag plate that pushes through the transparent glass façade. As the mast cantilevers at the lower and upper ends with a maximum free span of up to approx. 30 m, a particular focus was placed on the development of the tapered cross-sections, in which the deformation of the structure was restricted in order to limit the vibrations at the top.