Won: Blau.Quartier Ulm. Transformation of the shopping mall into a residential quarter
The ASTOC team with bauchplan ).( wins the Blau.Quartier, the transformation of the former Blautal-Center in Ulm into a residential quarter.
The Blautalcenter in Ulm, which only opened in 1998, is the largest shopping centre in Baden-Württemberg with 44,500 sqm GFA. Heavily challenged by increasing online trade, the Covid pandemic and local parameters, the vacancy rate at the Blautalcenter was recently at 80 percent. Only 25 years after commissioning, the decision was therefore made to make a fundamental new start: the shopping centre will be converted into a residential quarter with 1,000 residential units. In order to find the best solution for this challenging task, a cooperative expert procedure was launched with four invited planning teams.
The team ASTOC Architects and Planners with bauchplan ).( emerged as the winner of the two-phase procedure with a unanimous vote of the jury on 19.10.2023. This was announced by the project developers HLG Real Estate and DLE Land Development at a press conference on 26.10.2023.
The transformation of the Blautalcenter into a residential quarter has model character and will attract a great deal of attention not only in Ulm but also beyond the region. It is a task that can serve as a blueprint both in view of the imminent end of many comparable shopping malls and in terms of sustainability through the continued use of significant parts of the existing stock. The project also has a pioneering character in the context of urban development; it can form the prelude to an urban, mixed-use area and anchor housing in an intensively commercially used environment.
Initial situation and scope for the neighbourhood
Today, the Blautalcenter is part of a series of large-scale commercial buildings along the Blaubeurer Straße that are not very attractive in terms of urban space and have nothing in common with the common image of Ulm. A spatial edge is missing in most areas, the quality of stay is low. Compared to this, the picturesque space along the Blau River stands in maximum contrast. The Stadtregal south of the Blau already injects a pioneer residential use into this mixed situation, without which the new quarter would hardly be conceivable.
The existing structure - beyond the basement - is both a challenge and an opportunity: placing the majority of the new buildings on the robust existing reinforced concrete structure of the completely preserved underground car park of the Blautalcenter with its large spans and the associated clear grid leads to a dance in chains for the new development, which allows a lively and spatially versatile quarter to emerge from the grid and orthogonality. In addition, the existing skeleton structure on the ground floor and 1st floor, almost like in Corbusier's Maison Domino, also offers the luxury of free floor plans and unusual storey heights above ground, which charges the new buildings as an alternative typology.
Atmosphere through conservation and reuse
The transformation from centre to neighbourhood is a blueprint for sustainable urban development: from the principle of land recycling to the reuse of the supporting structure and individual elements. In the materialisation of the open space, for example, it is assumed that all identity-creating support materials can be obtained via the deconstruction of the existing mall and reused on site or reprocessed for reuse. Floor slabs or façade elements can be reused as path surfaces and plaza surfaces. Furniture and equipment will also be recovered from the deconstruction. Only vegetation, in the form of trees, climbing plants and green roofs, will be used to create a three-dimensional green quarter with character and microclimate. All other materials for the design of the public, semi-public and private areas are already on site, require careful harvesting, interim storage and new valorisation in the form of a model re-use concept.
The blueprint concept provides for the preservation of the existing building beyond the underground car park, the aim being to achieve the highest possible degree of re-use of the existing structure: the storeys, which are unusually high for residential construction, allow for a new type. Elevations above the two existing storeys that are to be preserved to the maximum create an exciting overlapping of old and new, which is also reflected in the construction and façade. Existing staircases from the shopping centre can be used in a new location, as can the wooden construction of the glass roof.
The reused materials are complemented by a canon of C2C-capable materials such as wood and ceramics; composite materials are avoided. Where passive solar shading makes sense, it gives the façades a deep relief. The roofs are activated and become the fifth façade. PV panels form an additional horizon and at the same time provide shade for the roof terraces and intensive greenery.
Spaces and addresses
Instead of the indoor mall, an open space is being created that connects the neighbourhoods. This and the boulevard on Blaubeurer Straße with its changing depths form further strands in the neighbourhood to complement the Blau. They are intersected by the central neighbourhood square, a wedge-shaped space that leads from the street across the Blau and connects the terrace in front of the Stadtregal with the squares on Blaubeurer Straße.
The northern buildings are accessed in an urban situation from Blaubeurer Straße and enliven the public space. The southern parts of the building sites have their addresses on the Blau and the bicycle route that accompanies it in a park-like atmosphere.
Structure and height development
On Blaubeurer Straße, six- to seven-storey buildings, staggered in depth, will in future enclose the large space and urbanise it. They are each made up of three to four individual buildings and have height accents at their ends that continue the theme of the heads of the first building phase already planned and rhythmise the courtyards. The landscape space of the Blau is characterised by L-shaped, staggered structures consisting of two existing storeys and two to four new building storeys built on top of them. The two high-rise buildings with 12 and 14 storeys mark the centre of the quarter.
The open space framework stretches between Blaubeurer Straße, which has been further developed into a tree-lined boulevard, and the green corridor along the Blau. The inner development element is a new typology of a neighbourhood alley that has been transferred from the existing mall. Its appearance is characterised by re-use and forms a jumping, pedestrian longitudinal development that links the new neighbourhoods in a three-dimensional interplay. This internal connection develops a hierarchy of different paths and squares and offers a range of different community uses, including urban gardening, community terraces or children's play areas. The green and open spaces along the path are developed at different heights to ensure a higher ground level for planting at selected locations and also to create different degrees of privacy for the uses on the ground floors. Re-use principles are clearly visible, for example, by retaining columns or whole areas of existing mall decks and integrating them into the design. In addition, existing elements are incorporated into the open space design, such as new paving or street furniture.
In the central articulated space of the overlapping construction grids, the neighbourhood square is created with a balcony function to the river. With possible uses for everyday needs attached to it, it serves as an urban everyday place for the new urban development. The users of the square are offered a mixture of commercial and non-commercial open spaces, with green areas and trees providing seating and shade.
The competition procedure
Procedure: restricted two-phase cooperative expert procedure, based on the Guidelines for Planning Competitions (RPW 2013).
Awarding authority: Blautal Grundstück GmbH
Project development: HLG Real Estate GmbH & Co KG + DLE Land Development GmbH
Procedural support: Faltin + Sattler FSW Düsseldorf GmbH
Procedure period: March 2023 to October 2023