Lakhta Center is a multifunctional complex located in Saint Petersburg, Russia, which includes two boomerang-shaped buildings and the tallest tower of the European continent, with its 462 meters of height standing in front of the Baltic Sea. Construction started in 2015 and is about to be finalized.
Maffeis Engineering developed the steel-ETFE roof over the internal plaza in between the glazed façades of the buildings. The roof is composed by steel arches with trapezoidal section, crossing in couples and sitting at a variable height that goes from 38 to 60 meters, being the profile of buildings inversely sloped. The resulting layout is a mesh of triangular and rhomboidal voids covered with three-layered ETFE cushions which protect the plaza from the extreme temperature outside, while bringing a huge amount of natural light to the ground floor. All insulating details have been developed in accordance with Russian norms to satisfy the strict requirements of the project, both from an aesthetical and a technical point of view.

The whole geometry has been studied with parametric software to control intersections between arches with different radiuses, inclinations and sections. Basing on a FEM model to perform the structural analysis, arches have been grouped in five types of trapezoidal shapes, according to the span which increases from the center to the end of the roof. On both ends, the structure is closed by two steel trusses made of CHS profiles, supporting the spider brackets from which two inclined glazed façades hang.
Maffeis Engineering also provided cutting patterns for production of the ETFE membranes, using parametric software to rebuild the perimetral system lines and to achieve a perfect control of the final curvature of the cushions.