ZOB, Central Bus Station
Nominated for the Mies van der Rohe Award 2017.
The city of Pforzheim, located in the Northern Black Forest in Germany, is carrying out sucessive changes to public areas surrounnding its main railway atation, in order to make the space more attractive to pedestrians.
An essential component of the areas reconfiguration is the new bus station, which features a total of 30 platforms housed under an elegant and prominent roof.
The roofscape of the new central bus station provides form to the hitherto shapeless area between the railway station and overpass, generating a new hub for modern mobility in a high-quality urban space. Instead of a monotone sequence of roofed walkways, an urban space has emerged as a real “place” with a high recognition value. Situated a suitable distance from the central railway station, the new central bus station presents itself as an extension to the historical building – a concise urban marker that gives form to the unsociable area to the east of the railway station building.
Roofing concept
The 1950s formal language of the historical railway station building is augmented with modern design. The rolling edges of the roof segments are inspired by the radii and loops typical of vehicle movement; the central bus station thus visibly manifests itself as a dynamic element in the traffic landscape of which it forms an integral part. Openings above the traffic lanes allow light and sunshine to stream through to the bus stops, whilst providing structure to the views from below and creating an interesting spatial experience through the organically evolving play of shadows.
Elements organised in a linear fashion form a compact summary of the central bus station’s necessary functions (information signs, time display, passenger information system and seating areas). They are small and easy-to-find islands of function – “places” rather than merely scattered individual elements. This achieves optical clarity, orientation and overview, enabling passengers to locate bus stops quickly and with certainty.
Roofing structure for the Central Bus Station
... an overview
The new construction of the Pforzheim Central Bus Station is part of a large-scale infrastructure development project, which, as well as improving traffic flows, will make a key contribution in urban development and architectural terms by upgrading the entire area.
... on the urban development
The roofscape of the new bus station forms an unstructured area between the railway station and flyover and a new modern mobility hub within a high-grade urban space. Instead of a monotonous sequence of roofed platforms, what emerged is an urban space as an authentic "venue" boasting high recognition value. Situated just the right distance from the main station, the new bus station appears as an extension of the historical building - a to-the-point urban marker, which breathes new life into what was an inhospitable area to the east of the station building.
The bus station submits to the superordinate scale of the main station by subdividing the roof area into three sections, benefiting from the head-turning visuals and significance of the latter within the urban fabric and provides thrilling views and insights into the districts north of the railway line.
... on the roofing concept
The language of forms employed in the original historical station building from the 50s has been upgraded with an element of contemporary design: The curved edges of the roof sections are derived from the typical radii and loops of vehicles in motion - the bus station features prominently as a dynamic local transport center. Openings over the lanes allow light and sunshine to flow into the bus platforms as well as structuring the view from below and enlivening the spatial experience with a varied interplay of shadow.
... on the furnishing
Linear arrayed elements encompass a compact summary of the required bus-station functions, such as information signs, a clock, passenger information system, text-to-speech units for visually impaired people and seating facilities. Small and easily accessible ‘functional islands’ as “venues” are favored instead of scattered individual elements. This also helps ensure visual clarity, enhances navigation and overviews and helps people find the bus stops they need swiftly and reliably. An ongoing series of tactile paving connects together all the stairs.
... on the lighting
Three lighting systems complement each other: Effect lighting, indirect and direct light. Using a range of lighting colors in a targeted manner helps create contrasts and makes it more enjoyable for users.
A row of lighting aligned with the roof contour is a key component of the architecture, emphasizing the dynamic nature of the form in the twilight and achieving a level of significance that belies the problem of overnight "desertification" of this area. The use of “lighting leaves“ on columns bathes the soffit in neutral white light. Units incorporated into the ceiling surface ensure targeted lighting of bus platforms. LEDs, built into the handrails, expand the lighting scope of the staircases, for easier navigation and improved security.
Accordingly, the roof spaces, columns, floorings, furnishings and lighting scheme all come together to form a single architectural whole.
... on the supporting structure
The steel supporting structure consist mainly of the columns and girder grids. The girder grids slowly fold downward, merging into the railway track area. The positioning of the columns reflects traffic planning and the use of areas under the roofing.
The columns comprise composite steel and concrete sections with internal cruciform reinforcement. This enhances the carrying capacity, sturdiness and durability. The base points are loose-jointed in both directions. Rising upward, the columns expand in a funnel-shaped design, which is stabilized by the internal cruciform reinforcement. From there, they are connected rigidly via welded brackets to the interfaces of the supporting clusters made of standard roller profiles on the girder grid of the roof;
this sees the girders and columns form multiple field frames in both directions.
The frame is used to reinforce the support structure. Fluctuations in temperature can be absorbed thanks to the flexibility of the “super-flex“ columns and via torsion at the base point.
The internal space-defining paneling of the supporting structure is formed using movable suspended cement-bound plaster supporting plates. The “graphical“ aspect of the required expansion joints underlines the dynamically elegant nature of the roof shell.
... on the drainage:
The roof space is drained via all the columns. This forms small drainage areas, minimizing the level of construction required for the necessary inclines.
