A wooden building for the harbor crown
09.05.2023
With the realization competition "Mehrzweckgebäude Hafenwestseite - Südspitze" the city of Neustadt in Holstein is looking for a project as the end of the promenade. The proposal of Urban Agency from Düsseldorf could convince the jury and landed on the 1st place. Timbatec was allowed to accompany the architectural office during the competition.
At the southern tip of the Westhafen Neustadt, an ensemble of buildings is being created that will act as a new point of attraction and as the end of the promenade. The diverse uses of the buildings will turn this place into a lively meeting space and thus create a new identification with the harbor.
Images: Urban Agency
The rear two buildings quietly weave themselves into the context with their clinker facade, while the architects gave the front building a special accent. From both a design and sustainability perspective, they opted for recycled copper facades. The idea is to use as much recycled copper as possible, with varying degrees of densification depending on current availability, and to add new panels where necessary.
Timber construction as the most sustainable solution
With regard to sustainability and responsibility towards our environment, the project is proposed as a wooden structure. In addition to the recycled facade, the cross-cutting themes of circular economy, sustainability and climate protection can be found in many other parts of the project. These include the fundamental priority on the use of recycled raw materials as well as the use of clay plaster in the interior spaces.
Ceilings with cross-laminated boards
The floor plans span uniaxial floor beams to form two- to three-span girders. This results in spans of up to seven meters. Ceilings made of cross-laminated timber prove to be the best solution. Due to the cross-laminated boards, the ceilings have a higher transverse stiffness, which is important for the stability of the building as well as for the vibration behavior of the long-span ceilings.
The slabs are supported by load-bearing cross-laminated timber walls that transfer the loads down to the foundation soil. The cross-laminated timber walls also serve to brace the building and provide the necessary stability. Here, too, the cross-glued laminations of the cross-laminated timber elements serve to increase the shear stiffness.
Load-bearing components made of solid wood in building class 5
The buildings are classified in building class 5. Load-bearing components are thus subject to the fire-resistant requirement (REI90). The Schleswig-Holstein State Building Code (LBO) permits fire-resistant building components made of combustible building materials by supplementing §26 (2). Load-bearing components made of solid wood in building class 5 are also permitted by the model timber construction guideline.
The walls of the necessary stairwell are also built fire-resistant with fire-retardant and non-combustible planking on both sides under additional mechanical stress. The solid wood construction of the stairwell represents a deviation from §35 (4) of the LBO Schleswig-Holstein, according to which the walls of necessary stairwells of building class 5 must have the design of fire walls and these must consist of non-combustible building materials.
This deviation must be applied for and justified: The protection goal of impeding fire entry into the necessary stairwell for a sufficient length of time and allowing the use of the escape routes for a sufficient length of time is achieved because the fire retardant non-combustible planking on both sides protects the wood structure for at least 30 minutes. Since the cross-laminated timber wall is also load-bearing and room-enclosing fire-resistant (REI90), the stairwell wall achieves an overall fire resistance of 120 minutes.
Images: Urban Agency