Refurbishment of the Court of Strasbourg
After the French defeat in 1870 and the loss of Alsace-Lorraine to the German Empire, Strasbourg paid a heavy price. Unchanged since the 15th century, this historic town had to adapt. The adoption in 1878 of a development plan designed by a municipal architect Jean Geoffroy Conrath planned the expansion of the city to the north, beyond the fortifications of the 17th century. The desire from the new imperial power to found the Neustadt, or “New city”, responded to the need to establish its authority within an exemplary capital with official buildings and housing. Stretching beyond Ill Canal which later became the Canal du Faux-Remparts, the Neustadt was the place of some remarkable constructions such as the station (1883), the Palais de l’Université (1884) or the Palais Impérial (1888), creating a common eclectic construction style. The Neustadt was associated for far too long with a painful period in history but is today the symbol of an unwavering French-German reconciliation underpinned by a strong European culture. The restructuring of the Strasbourg railway station in 2007 by the SNCF architecture agency Arep, which fits snuggly under a glass shell, triggered the town’s awareness which then embarked on a drive to protect the future of the buildings in the Neustadt. After the university library was restored in 2014 by the architect Nicolas Michelin, it was time for the Palais de Justice – built in 1898 by the architects Johan-Karl Ott and Skjold Neckelmann – to gain a new leash of life. This exceptional building of 14,920 m² was part of a large-scale renovation project between 2014 and 2016 carried out by the Spanish Architect firm, Garcès-de Seta-Bonet. Located within a densely populated area, the massive building has four grey sandstone facades displaying classic architectural elements (pediments, low relief carvings, columns…). Yet transforming an historical 19th century building into a 21st century court house requires the functional needs of modern public equipment to be supported whilst incorporating updates to comply with security standards applicable to establishments servicing the public (ERP rules). Well-designed from the outset, the internal functional organisation was preserved and adapted to current challenges, with people flow reviews depending on the changing trends in use and the creation of an extension. Designed to hold 225 magistrates and civil servants, this mammoth project involved three delicate construction sites which were located in the heart of the Alsace capital.
A steel origami roof
One of them involved the careful restoration of the listed elements on the supplementary inventory of historical Monuments (1992), which included the facades and skylights, the entrance lobby and the Salle des Pas Perdus with its galleries and staircases, and the court room and its decor. Alongside this, a major renovation of 12,300 m² of floorboards was started as well as the construction of a new section of 6,024 m² in the central yard of the building: thereby increasing the surface area without increasing the floor space. The added section houses the court rooms and the original section houses the offices. Opening out onto the Salle des Pas Perdus, a new landscaped patio has been embedded in the building in order to promote natural light and to be used as an area for people to flow through which is separate from the access areas for staff and prisoners. After a detailed analysis of the existing condition, the architects chose to eliminate the 1978 extension and to replace it with the construction of four partial levels slightly set back from the existing facade to avoid interference. The implementation of a steel framework with steel columns and collaborative floors made it possible to free up large areas quickly and with little disturbance. Although the building was extended by almost 60% of its original surface area, the designers ensured that the extension was the least visible from the street. The latter is topped off with an aerodynamic roof in stainless steel which, as it takes off from the stone parallelepiped, ennobles it and gives it a certain level of modernity. Like a wise origami, this roof which is sculpted by four folded facets topped off by skylights, is surrounded by a steel ring with variable geometry. This complex device implemented on the perimeter of the roof includes a metallic structure in trapezoidal shapes using wood, itself covered in Uginox Top 304 steel bands from Aperam. Customised cut-length sheets from coils 500 mm wide and 0.5 mm thick, the visible strips of 430 mm wide were laid traditionally with standing seams. With a mat appearance, the same definitive and long-lasting,material was implemented in the form of cladding of 2.35 metres high which covered the upper area of three of the four facades of the building and ensures continuity with the slates. In the end, the thoughtful actions of the designers contributed to magnifying the original architecture whilst at the same time adding a number of contemporary touches developing enduring connections between several construction periods.