The façade system and its components: geometries and trasparency

The outer envelope comprises several different custom-made façades. Technologically highly demanding, these different façade typologies had to meet the requirements of the architectural design but also take into account the particular solar exposure. 

Architecturally, the south façade is the most striking aspect of the tower. The continuous staircase running through the Study Cascade follows the cantilevered volumes down through the building, each segment emphasized by broad GFRC bands. The total see-through transparency of the façade reveals the network of social and study spaces distributed across oversize landings. It is as if this 14-story glass tower has had its outer skin removed to reveal a sectional view of the Cascade’s skeleton. The other three sides of the tower are made up of a continuous glass and aluminum unitized curtain wall with glass fiber-reinforced concrete elements. While each façade displays slightly different technical characteristics depending on orientation, the integrated glass fiber-reinforced concrete strips create a single wrap-around unit. The glass-fin façade is today one of the most transparent forms of structural glass façades.

Developed by Josef Garter USA, a division of Permasteelisa North America, it extends up the full 14 stories of the building. Aesthetically pleasing with no visible metal connections, this fully transparent unitized wall is also highly energy efficient, thanks to the low-e coated low-iron glass. In order to ensure a completely transparent façade, each element had to be custom-developed in order to take its designated place in the tower’s particularly complex envelope. All aluminum connecting elements are concealed inside the floor slabs or stringcourses while the glass panels are supported internally by different size laminated glass fins, the tallest of which measures 9 m (29.5 ft). Aptly called a glass-fin façade, it is supported by vertical profiles comprising three layers of stratified safety glass that extend for one or more floors. These profiles transfer the wind loads and dead loads of the façade onto the floor plates. The double-glazed panels are connected to the fins with a snap-on aluminum fastening device. In this way, the weight-bearing aluminum profile on the vertical fin and the glazed panels of the façade become a single structural system. Each glass fin had to be a one-off unit, a requirement that added to the technological complexity of an already challenging project. Apart from the connections on the structural glazing, no other mechanical connecting systems were used to fix the elevations to the structural frame. A further constraint was the fact that anchoring pins could not be used on account of the very high-density components and post-tensioning cables making up the floor plates.
The deliberately ‘inefficient’ spaces of the Study Cascade contrast with the north, east and west sides whose strictly regular grid is designed for specialist activities. The outer envelope enclosing the lecture rooms, laboratories and other dedicated areas shield the environments from direct sunlight and allow only muted views through continuous, full-height windows developed by Permasteelisa North America. Separated by the round-edged GFRC strips, the characteristics of the glass panels change from one floor to the next depending on the functional requirements of the interior environment and the particular solar exposure.