Urban Loritz Platz

The Urban Loritz Square on the Vienna Gürtel is a centrally located public space and a major public transportation hub, where several streetcars and subways connect. Transforming the formerly unappealing and entangled traffic hub into an attractive, contemporary urban space, the new design for the Urban Loritz Square heralds the revitalization of the entire Gürtel region.

The design reorganized the traffic patterns of streetcars, cyclists and pedestrians to achieve a clearly ordered public space. A light and airy steel structure with a membrane roof shelters the main paths and waiting areas. The overarching cover not only protects the square from the elements, but also emphasizes a sense of general unity and urban orientation. At night, the entirety is illuminated by indirect light, reflected off the translucent membrane. The membrane roof leads to the base of the grand public stairs of the new Central Library, completed by the City of Vienna a year later.

Structural System
The membrane roof has a total length of 140 meters. Due to the subway tunnel under the site, all the loads had to be brought down vertically to keep foundations minimal. The numerous streetcar tracks under and adjacent to the roof posed an additional challenge since they prevented backstays or ties. Therefore, the structural system consists of steel arches on supporting pillars that transmit all loads directly into the foundation. In all, the roof consists of ten membrane sections and rests on 28 steel supports. Horizontal forces are absorbed by tie rods. Six inclined pairs of arches converge at the ridge, which are supported by four columns each. The membranes stretch between the double arches. The narrow section of the roof consists of four cantilevered arches that rest on four pillars. In essence, the membrane floats above the street.