Dummy testbed “Kleiner Grasbrook” Hamburg

1. Background

From January to April 2018 we were doing the first comprehensive test of the developed U_CODE process. For this we used real data about the urban planning project redeveloping the quarter “Kleiner Grasbrook” in Hamburg. With that as a starting point, we were going through the whole U_CODE process, including collective briefing and designing with the public and a professional design competition leading to a finished and ready-to-approve design proposal. For this we set up a community of more than 100 citizens which was guided through the participation process by our newly created role the Super Moderator (SuMo), thereby enabled to provide their knowledge, opinion and ideas on the project as well as to design their to-be-developed quarter via easy-to-handle tools. The results were meant to be integrated in the professional design brief, thus qualifying the basis for the design expert work. This testbed delivered a proof of method for the U_CODE process and a proof of tools for first developed tools which will be further developed in the upcoming development stages.

2. District "Kleiner Grasbrook Hamburg"


The Kleine Grasbrook is a district in the district of Hamburg- Mitte of the Free and Hanseatic City of Hamburg. In the small Grasbrook are almost exclusively facilities of the Port of Hamburg. Since the handling of goods has shifted further to the west due to the use of containers in the container terminals located downstream, many areas are fallow, so that a re-use of the area is planned. The area was also designated as the venue for the 2024 or 2028 Olympic Games. The former inland island lies between Veddel (upstream), Steinwerder (downstream) and Wilhelmsburg in the south. On the opposite side of the Norderelbe lies the formerly connected island Großer Grasbrook, which is adjoined by the center of Hamburg. The name component -brook refers to the fact that it used to be a low-lying, humid, broken land. As part of the U-CODE project (Urban Collective Design Environment Professional Design Brief), a sub-area is planned and redesigned. The aim of the urban planning concept is to locate the area in the existing ensemble and one train new address in Hamburg.

On the one hand, the design promotes the readability of the spatial edges, on the other hand, it defines various open spaces and space structures. The guiding principle is to organize the district in its complexity and to link individual public structures. Both the positions and the shapes of the new buildings bring about a deliberate reorganization of the area with the goal of making clear open space typologies legible. Concise, usable and attractive open spaces are being developed, supporting a shift from the place of industry to the place of active living and working.


The building construction is economically chosen with regard to manufacturing, operating and maintenance costs. The selection of materials took place under the aspect of ecological sustainability. In essence, the use of concrete, steel and glass is suggested as these materials are fully recyclable are. In addition, the concrete construction has a high energy efficiency and a long service life, so that only small additional life cycle costs are to be expected. For all structural component connections, thermal bridge-free details are chosen.

3. Concept "Spine"

Public open spaces and buildings are organized by the linear ‘spine’ which is formed by a boulevard in the centre of the peninsula. The ‘spine’ connects a sequence of spaces: A twin tower ensemble in the southeast forms a gate as an entrance gesture for the peninsula. Behind the gate lies the main public square with a solitaire building for the community centre. Residential blocks with green courtyards are subsequently lined up on both sides of the boulevard. In the centre of the peninsula semi-public greens of the residential buildings are positioned directly along the spine creating variation through expanding the open space. A free-standing structure at the end of the spine forms a focal point and accommodates the primary school which benefits from the surrounding public park which extends to the head of the peninsula.


The concept achieves the green ratio target of the brief. The public park in the west of the peninsula provides an environment for leisure and is linked to the pedestrian loop around the peninsula. The semi-public spaces associated with the residential buildings provide a high residential amenity. Direct visual connections from the spine to the water are provided along the lanes between the buildings blocks. Office use is accommodated in the southeast as a buffer against the traffic noise. Sheltered from the noise exposure extends the residential use between the two end poles of the spine. Public uses are provided on the lower levels of the twin towers in addition to the solitaire on the main square which accommodates the community centre. At the opposite end of the spine is the school building positioned. Retail and gastronomic use are located within the ground floor levels along boulevard. A new pedestrian bridge connects the peninsula with the public transport stations in the northeast (u- & s-bahn).

The point of entry for the vehicular access is designed through the gate formed by the twin towers. The main boulevard is divided into two one-way-lanes for cars. The tree-lined path in the centre of the boulevard is designed for a footpath and cycle track. The residential buildings are accessed by culs-de-sac (vehicular access) which alternate with treelined lanes for pedestrians leading to the waterfront. The edge of the peninsula is kept accessible for the public allowing a loop-walk around the peninsula. In line with the current flood protection regulations all buildings are placed on plinth at +9.20M above sea level. The top of the plinth is 3.80M above the existing peninsula and accommodates the necessary car-parking below the buildings. The use mix meets the provided targets with around 70% for residential use. The scale of the developments respects the height limit of 30m laid out in the design brief with the exception of the twin towers in the which are intended to from a landmark with a height of 65m.

4. Concept "Central Park"

A central park forms the centre of gravity for the new development on the peninsula. The park is placed in the centre of the island and repeats the contour of the peninsula. The majority of the residential developments are laid out along the perimeter creating addresses with a strong identity. The arrangement is complemented by an ensemble in the south-east consisting of a commericial building with an open courtyard in the center and two wings in front of which the community hall and other public functions are accommodated. This group of building forms the entree of the entire development. The courtyard of the commercial building is an open, public square and can function as a venue for cultural activities and markets. The public building of the primary school is located at the northwest adjacent to the public park on the head of the island. The semi-public green areas of the residential blocks extend towards the perimeter of the peninsula as part of a continuous landscape concept.


The open structures of the residential buildings allow unobstructed views to the water for the residents. The concept achieves the green ratio target of the brief. The public park in the centre allows various uses and can accommodate also small pavillons for cafés as well playgrounds. The head of the peninsula is designed as a park which ties into the loop-walk along the waterfront. Office use is accommodated in the southeast as a buffer against the traffic noise. The residential use encircles the park fully. Public uses are provided in the southeast alongside the formal square. The school building is positioned in the northeast. Retail and gastronomic use are located on the ground floor of the office developments as well as on the formal square. A new pedestrian bridge connects the peninsula with the public transport stations in the northeast (u- & s-bahn).

The vehicular access is designed as a ring road around the central park from which cul-de-sacs provide access to the developments. Cyclists and pedestrians can surround the peninsula directly on the waterfront. Ample paths for pedestrians and cyclists are connecting both sides through the park in the centre. In line with the current flood protection regulations all buildings are placed on plinth at +9.20M above sea level. The top of the plinth is 3.80M above the existing peninsula and accommodates the necessary car-parking below the buildings. The use mix meets the provided targets with around 70% for residential use. The scale of the developments respects the height limit of 30m laid out in the design brief.

5. Concet "Unknown pleasure"

The Hamburg peninsula „Kleiner Grasbrook“ is currently being used commercially / industrially. A study will examine the extent to which a restructuring into a working and living environment is possible. The basis of this study is the evaluation of a public survey on wishes and opinions on this project. Content of the present draft is the urban reorganization of the subterritory Moldauhafen.

© Jörg Höfer

On the basis of the evaluation results and the existing situation on site, a development is proposed that establishes a heterogeneous urban environment taking into account the specific area edges. Three characteristically different city fields are offered: the arched bank edge to the Norderelbe acts as a hard edge and defined conclusion. Towards the south a change of direction of the building structure with decreasing building heights takes place. The two main structural directions simultaneously define the paths of pedestrian and bicycle development. The motor vehicle circulation refers to the three area poles: bridge, peninsula tip and connecting boundary to the eastern part of the peninsula. Atmospheric, the northern part along the Norderelbe is determined by the six-story buildings and a port-like area structure. Residents, cyclists and pedestrians at the same time use the paved surfaces. The southeastern part of the design area includes uses such as living, working, training, care. Places and meadows alternate. Bicycle and footpaths are accompanied by rows of trees and facilitate orientation. In the southwestern part are green areas with opportunities for sports and recreation. The whole results in an area that loosens from north to south. The north coast is dominated by an east-west promenade. The south coast is crossed by green areas.

The circulation concept deliberately overlays motor traffic, pedestrian traffic and bicycle traffic. The overlapping is widespread in the north and differentiates more to the south. The contact to the neighboring areas takes place in the south over a new bridge and in the east over the connection of the established main traffic artery. The following points of the evaluation are more strongly reflected in the present draft:

6. Professional Design Brief

Urban design

The design area is located in the northern harbor area in the heart of Hamburg. The area is located opposite the development area of the Port of Hamburg. An exciting height grading of the new buildings ensures a pleasant structure along the water and meets the existing typologies. The eaves height of the new buildings is based essentially on those of the existing scale. An additional staggered floor mediates between eaves and ridge height and ensures a reasonable scale to the adjoining urban and natural space. The formation of a basement level allows the uncomplicated realization of a promenade as well as the raising of the ground floor level above the minimum height required to prevent flooding. The aim of the urban planning concept is not only to generate a spatial and urban integration of the adjacent areas, but also to promote lively social and intercultural exchange.


Free space

Naturally, the area is on the border between the Tertiary city land and the port of Hamburg. Bracketed by a „hard edge“, the Hafencity, and a „soft edge“, the moat, the open space planning goal is the connection and interlinking of the periphery on the property of the residential, working, and cultural plant. „Culture“ intertwines with „nature“. Work, land use and the environment are important aspects of the design of the open space on the design site. On the property, NW-SE aligned, asymmetrically arranged strips intertwine the contrasting edges.

This principle is followed by the buildings with their green roofs and courtyards as well as the elements of the open space design and the development structures. In the interstices of the buildings, spatially decoupled from the development level, both communication spaces and retreat spaces are formed, which invite them to linger. The courtyards of the new building are characterized by differentiated green areas with groups of trees from local fruit trees. Plate belts with large lawn joints alternate with different seating options. In the „courtyard“ of the development area there is a generously designed green area, which is inviting to stroll and relax, which underlines the flowing transition between nature and city noticeably. Passenger car traffic opens up the property from the „am Holthusenkai“ road via a peninsula bypass, at which car parking spaces are arranged, additional parking spaces are located under the new buildings.

Inner structure

The design pursues the concept of generating compact, economically and structurally sophisticated city blocks. It is not a large anonymous housing development, but smaller compact residential buildings and office buildings created. Bilaterally the individual apartments with EW orientation are economically organized.


On each floor there are also residential groups. The flexible floor plan structure makes it possible, if necessary, to combine further apartments into residential groups. All buildings can be optionally retrofitted with a passenger elevator in the area of the staircases to ensure barrier-free access to all areas. On the ground floor, multifunctionally usable economic areas are provided with an outside reference, which due to their location can also be reached without a lift.


With regard to the manufacturing, operating and maintenance costs, an economic building construction is chosen. The selection of materials takes place under the aspect of ecological sustainability. In essence, the use of precast concrete and glass is suggested because both materials are fully recyclable. In addition, the concrete construction has a high energy efficiency and a long life, so that only small additional life cycle costs are to be expected. The structures are used as reinforced concrete skeleton construction with columns, reinforced concrete floor slabs and stiffening reinforced concrete walls and designed. The massive primary construction is supposed to have an uncluttered climate-regulating effect in essential parts. A modular arrangement of precast concrete columns, as well as a regular media guide increases the flexibility of the floor plans. Walls and installations are freely selectable in the selected grid. This maximizes the necessary adaptability in the frame later conversions or changing user needs. The economic sectors are in accordance with the client with accordingly ergonomic, health beneficial Wall coatings and coverings. Room acoustically effective measures are required in the Interior fittings integrated.


The facades of the new buildings should have a modern look and those of the Hafencity not be behind. These are intended to give the buildings an innovative and noble character. Material proposals for curtain facades would be metal, concrete, eternitite and bricks. Lots of glass should also emboss the appearance of the area. The floor-to-ceiling triple glazing guarantees light-flooded interiors and ensures an optimal energy balance during the heating season. All rooms are equipped with an interior blackout blind. Massive wall areas reduce the glass surface area. In the structural component connections, thermal bridge-free detail solutions are selected.

Energy and technology

The aim of the energy and technology concept is to achieve a high level of efficiency with minimal installation, taking into account future operating costs Energy efficiency and comfort in the building produce. In particular, architecture and building construction should contribute to an energetically favorable overall balance. On reason of the good A / V ratio are best properties for summer and winter heat protection already in the draft created. The buildings are designed so that the passive solar gains over the windows are as large as possible. There is none Individual rooms, which are oriented to the north. All lounges have thermostats and radiators, which means a room-by-room temperature control is possible. In order to reduce primary energy demand, geothermal support is proposed with Profitability studies is to be examined. For domestic water heating, roof areas are being installed Solar thermal systems held. The buildings have appropriate technical rooms for connection and distribution of all necessary media. These are each arranged on the ground floors flood-proof. In the easternmost new building, which outside the flood-prone area, central technical and workshop rooms become contiguous in the basement level organized. The extensive green roofs can be used to collect rainwater and associated greywater use be used.

7. Conclusion

The results review of the test run can be split up in three parts: Proof of Process (overall procedure), Proof of Method (individual steps), and Proof of Tools (instruments related to each step).


Proof of Process

The overall process worked well and can be accounted a success. It generated feasible design results and give a qualitiy advantage compared to other existing public participation processes, which have often no comprehensive concept to ensure the ongoing participation and use of inputs. In the DTB about 120 partici-pants worked together, 40 contributions were collected during the Co-Brief, 20 Co-Designs proposals devel-oped, from which 5 professional design proposals were generated.

The dummy stakeholders worked well during the DTB, especially the communication between all “professional” stakeholder groups were unproblematic. However, the addressing of the “public” turned out difficult, as instruc-tions were often not understood. Some public participants wanted to invest a lot of time and know all available information, while others only wanted to spread their ideas and knowledge as fast and simple as possible.

Proof of Method

Assessing the conduct of the seven single steps, the first two steps, Initiation and Harvesting were executed without major problems. However, HOvhothe analysis of the harvested comments appeared difficult. As expected, the Co-Design phase was the most challenging one. A usable dummy tools for massive serious gaming was developed in the shape of Google presentation mockup. Focus Group tools were not used in this testrun. In the Professional Design phase, two of the five designs were created without being based on the input of the Co-Design, due to delayed analysis of the co-design input. The Ranking/Voting Phase was carried out by ranking both professional and laymen designs. Design Integration and Acceptance were carried out as ex-pected without problems.

Proof of Tools

Many specific learnings could be drawn for the development of the actual tools from dummy tools, e.g. about the necessary level of facilitation during the Co-Design. Social and psychological aspects re. the overall process became visible, the problem of e.g. acceptance of non-professional design works by professional designers.