The world’s largest cosmetic company, L’Oréal, has renovated its headquarters located in Paris. During this renovation, a cutting-edge glass façade was built in the building’s courtyard, consisting of a meshed lamellar-type conical tower topped by a spherical dome.

The total height of the glass façade is 25.0m from the ground floor level and the width is approximately 9.0×12.8m. The steel frame is a lamella type structure composed of quadrilaterals and triangles. The geometry was managed through a 3D parametric model with Rhino and Grasshopper that was adjusted for the double curvature capabilities of the glass manufacturer. The steel structure is made up of 3D curved tubular beams and reconstituted straight welded profiles, which were subjected to a strict dimensional analysis by means of 3D scanners to ensure the structure’s assembly. The connections between the profiles have been done using complex 5-axis machined structural nodes and hidden prestressed bolts.

The glass façade is composed of double-curved fritted and tempered laminated insulating glass panels which are two sided supported by the primary 3D curved hollow sections and a bespoke stick curtain wall. The glass façade is crowned by a spherical glass supported on its entire periphery with natural ventilation around it provided by 13 motorized windows.

The verification of the structure considered second order effects and global imperfections using a finite elements software where the joint stiffness played a vital role. Advanced finite element software was used to determine it and it was validated through experimental tests.