ETH Zurich Atrium roof of the BSS research building

Basel 2020 (CH)

The free-spanning glazed roof covers the atrium of the six-storey BSS laboratory and research building in Basel.

The single-layer grid shell structure made of hollow steel profiles consists of a perimeter tension ring mounted on the concrete structure underneath and a double curved triangular net.

Prefabricated in 7 assembly units, the shell structure was transported, and without additional supports, hoisted into position and welded.

The centrepiece of the shell structure is the new type of interface node made of Ø 220 mm round steel. Unlike conventional methods, the distinctive feature of the RUCH node (patent pending) is that the steel cylinder, which forms the centre of the node, is unprocessed and that accurately fitting laser-cut RHS 160×80 steel profiles are welded onto the node.


Glass analysis, detail design for steel nodes, workshop drawings for shell, glass cutting, assembly and transport calculations

Nickl & Partner Architekten AG, Zürich

structural design
Leonhardt, Andrä und Partner, Berlin

roof, production + assembly
Ruch Metallbau AG, Altdorf

BGT Bischoff Glastechnik

glass system
RAICO mit unsichtbaren Windsoghaltern und oberflächenbündiger Silikonfuge

AURA Foto Film Verlag
Emmenbrücke im Auftrag von Ruch AG


glass surface
529 m²

covered area
512 m²

snow load
0,9 kN/m²

wind pressure
1,58 kN/m²



insulating glass units
12 mm fully thermally toughened safety glass heat-soak-tested
18 mm air space – laminated glass made of 2x heat strengthened glass with PVB-foil