With a balance sheet volume of over 20 billion euros and around 750 employees, the IB.SH economy, housing and urban development, municipalities, labor market and educational measures, environmental and energy projects as well as the agricultural sector in Schleswig-Holstein. The central development institution combines loans with state, federal and EU funding.
The structural design of the new IB.SH building was accompanied by extraordinary requirements in many areas. In particular, the location close to the shore of the Kiel Fjord in combination with the urban planning requirements demanded extensive solutions. Against this background, model-based planning was the first choice - especially when all those involved in the planning (engineering team Trebes, BAM Deutschland, Heinle Wischer und Partner Freie Architekten, RMN Ingenieure) have extensive expertise! Our team regularly compared all 3D technical models across all planning phases. The formwork and reinforcement plans were derived from the model, so that we achieved LOD 400 for the structural design.
The limited load-bearing capacity of the in-situ soil layers in the immediate vicinity of the Kieler Hörn bank wall required a pile foundation. Here, the position of the 721 piles had to be coordinated with the excavation pit and the integration of the building structure into the subsoil had to be limited.
In order to minimize the lowering of the groundwater, the formation of beam grids or pile heads was ruled out. Using historical documents, we determined the position of the existing pile foundations and, together with the client, investigated whether the existing foundation piles could be used to support the new building loads. As this was not possible, we designed the new pile foundation to be flexible enough to react to the position of the existing foundation components.
In order to optimize the construction process and the formwork systems, we designed large parts of the façade structure as a prefabricated construction in addition to the flights of stairs and the interior supports.
To optimize the component geometry and the required reinforcement, list mats were used in the area of the basement walls and the floor slab.
The pipes for thermal activation and office ventilation are integrated into the storey ceilings - with minimized construction height.
The underground garage binds approx. 4 m into the ground and is largely below the groundwater horizon. This meant that the entire basement had to be implemented as a waterproof construction for pressing water and the groundwater level had to be temporarily lowered by 3 m at the start of the construction phase. For the design of the underground garage, we worked with the civil engineering department to develop load approaches for the publicly accessible area. The city of Kiel placed very high demands on the flexible use of the walkway areas. During the subsequent design of the supporting structure, extraordinary requirements arose in order to ensure that every area of the parking garage could be driven under completely.
The load-bearing structure of the above-ground storeys followed the urban planning specifications in classic solid construction with red clinker brick. In order to meet the requirements of the building and plant technology, the building was designed with a flat slab structure. Interfering beams were avoided despite the considerable spans.
In terms of flexibility, our load-bearing structure concept ensures a variable room layout that can be easily adapted by users at a later date!
The two almost equally sized 5-storey building sections are connected via the street "Zur Helling" by a bright, glazed walkway on the 3rd floor and the underground parking garage.
Ten branches in a future-oriented office complex - that was IB.SH's brief at the start of the construction project. The end result was sustainability certification in accordance with the DGNB Gold standard. This meant that all ecological, economic and social aspects had to be fulfilled - from the planning and construction to the operation of the building.
In this context, the question of sustainable energy generation was essential, which IB.SH and the planners answered with a bivalent reversible (brine) water heat pump system using the Kiel Fjord as a heat source.
