Administration Weidenbornstraße, Wiesbaden (DE)

The administrative offices spread all over Wiesbaden no longer meet today’s demands for proximity to citizens, sustainability and technology. For this reason, the Hessian state capital is building a new, central administration building near the main railway station that will set a forward-looking signal in terms of climate protection, sustainability and carbon footprint.

Urban context
With our design for the 7,400 m² corner plot, we are adding another key component to the up-and-coming commercial and office location close to the city centre. The long, five-storey block along the district boulevard is elevated on the ground floor and thus creates a spacious passage with visual connections to the surroundings. This avoids a closed perimeter development and still allows us to remain true to the concept of a hard edge on the street side with a loosened structure on the back. The inner courtyard as an enchanted garden forms the heart of the new building. Accessible from all sides, one is immersed in a wild landscape of flowers and grasses. Steps and seating around the central water basin invite to relaxation or communicative meetings. Together with the green roof and façade, the courtyard fulfils an important bioclimatic function in the urban environment.

Organisation & Function
A generous staircase with a lateral barrier-free ramp leads across the passage into the inner courtyard. To the north of this is the common public access to the offices, while the staff entrance and delivery are on the southern side. The staircase in the multi-storey entrance hall takes visitors to the central waiting area on the first floor and the entrances to the offices. A café on the ground floor enlivens the district boulevard.
The building’s depth of 17 metres allows for flexible use of the office space, whether initially as cellular offices with a central zone or later as combined offices or open space areas. Three staircase cores provide access to the individual floors, which are divided into approx. 400 m² use units. The central circulation zone leaves the entire façade areas free for workplaces. The regular “leaving out” of some offices creates niches, communication zones, air spaces over several floors, shortcuts or outdoor spaces as well as exciting views.
The parking and bicycle garage along Weidenbornstraße is organised in an extremely compact way to seal as little floor space as possible. A system car park is quickly erected and, much more important, quickly dismantled for a time when there is less individual traffic. In this case, the parking garage can be replaced by additional office or residential buildings.

Material & Construction
The building is conceived as a timber hybrid. The upper floors are designed as a pure timber construction with timber columns, a continuous solid timber ceiling and a curtain wall element façade made of timber. Only the ground floor, the staircase cores and shafts are solidly constructed. The façade, in which always two construction grids form a façade module, also shows the modular construction to the outside. The multi-storey car park and the three-storey foyer annex are spanned with ropes, which over time become overgrown and turn into green building blocks.

Structural framework
A large, simple table made of hollow-core reinforced concrete with a cantilevered slab on all sides creates space in the free passage and, together with the stiffening staircase cores, creates the basis for the four-storey timber construction. On the upper floors, only columns and beams made of beech form the longitudinal façade and corridor wall axes, on which large-format ceiling panels made of cross-laminated timber are simply laid. This means that there is no need for load-bearing interior walls, but that drywall can be erected as needed and later moved again. The result is a building construction that is just as impressively simple and appealing as it is extremely economical.

Building technology & sustainability
The building technology ensures an ecological and economical energy supply for the building. District heating and a photovoltaic system on the roof are efficient and ecological energy sources. The green areas are watered with rainwater collected underground. The hybrid ventilation concept combines mechanical supply air and natural ventilation.
Matching the ecological timber construction, plant-based insulation materials such as wood, straw, reed or hemp are used. These are completely compostable and at the end of their life cycle form the basis for renewable raw materials.

Client: Federal State Capital Wiesbaden, Liegenschaftsamt
Location: D-65189 Wiesbaden, Weidenbornstraße
Architecture: Dietrich | Untertrifaller
Project Management: Julia Schmid
Competition: 2021
Bauzeit: 2021-2024
Area: 9,700 m² GFA
Capacityt: offices, shops, café, parking and bicycle garage

statics: Merz Kley Partner, Dornbirn / sustainability: ZWP Ingenieure, Wiesbaden / landscape: Storch Landschaftsarchitekten, Dresden /// rendering: Dietrich | Untertrifaller