Reach higher with wood:
 84 meter, 24-storey ‘HoHo’ tower



Rüdiger Lainer and Partner set to build the world’s tallest wooden skyscraper

Architecture firm Rüdiger Lainer and Partner (RLP) has unveiled plans to build the world’s tallest wooden skyscraper in the Seestadt Aspern area of Vienna. The 84m, 24-storey twin tower project dubbed ‘HoHo’ will house a hotel, apartments, a restaurant, a wellness center and offices. 76 percent of the structure will be constructed from wood, which will save a phenomenal 2,800 tonnes of CO2 emissions over similar structures built out of steel and concrete.

According to the architects, wood is very popular in Austria as a building material, especially in rural areas. And with good reason: wood is a resource that is produced faster than it is consumed, and is now one of the most affordable materials with a high emotive quality. In addition, excellent Austrian engineering services for timber facilitate its implementation in construction.

Current technical possibilities offer opportunities for the use of wood as a key element in high- rise construction. In light of these positive developments, RLP has developed its wooden skyscraper concept, which is nearing approval for construction in Vienna. This project will be realized by the
 real estate developer cetus Baudevelopment GmbH, under the dedicated leadership of Caroline Palfy.

At the time of its proposed construction start in the fall of 2015, the tower will be the highest building made of wood in the world. The completion for the tower, which will comprise 24 levels, is expected in 2017 and the cost of development for the Kerbler Group is EUR 65 million. Upon completion, the project will snatch the title as the world’s tallest timber structure from Melbourne’s Forte, which currently stands at 32m high.

Concept
According to RLP, the basic approach is to combine a timber structural and construction system with an efficient building layout. In comparison with pure timber construction, the ‘HoHo’ tower will demonstrate the advantages of 
a hybrid construction: supporting concrete cores are used for 
vertical access and supply. The self-supporting timber structural system is then secured to these cores, creating the volumes for the building’s varied uses.

All of the materials will be utilized to best suit the different requirements of structural engineering, fire protection, flexibility, economy and
spatial quality. In this way, the fundamental requirements for the use of a high-rise building – with its strict building regulations – can be met. Further, the architects estimate that up to 76 percent of the building from the ground floor up will be made of wood.

Urban design
The project is located in the heart of Vienna’s urban lakeside in the northeast part of the city. It sits in a prime location between the Lake Park and the square next to the subway stop. This central area of the new city district is being developed based on the urban concept of RLP. The varying heights of the tower volumes, derived from the requirements of urban planning, are the defining elements of an urban silhouette along the lake.

Of course a consideration is made not just for the wooden tower’s appearance from afar, but its contribution to everyday life in Vienna’s urban lakeside. As such, the lower levels are extended with a sheltering canopy to provide pedestrians and users with an experience of the building on a human scale.

Sustainability and flexibility
The timber construction system provides high efficiency in 
terms of thermal insulation and serviceability. Wood-composite floors are secured to the central concrete supporting cores, and extend out to the building edge. These floor panels are supported by a wooden column system around the outline of the building. This structure then supports pre- fabricated external wall modules that combine solid wood panels with an ‘earthy ’ concrete shell to form the building’s facade.

The inside surfaces of the exposed wood ceilings, columns and the outer wall create a sensual, natural atmosphere. The modular design and flexibility of use result in a high building serviceability. Serviced apartments, offices, restaurant and spa facilities are provided within the tower. Further, subsequent changes in user or building function can be performed efficiently.

The sustainability of the new wooden tower results from the pooling of conceptual approaches: wood is resource-efficient, also in terms of its embodied energy. The flexible and adaptable layout ensures that the wood tower
can be used for a long time – this longevity is an essential factor in the consideration of efficient sustainability. And as established in the concept of RLP for the high- rise building, the goal is to ensure that economy and ecology become mutually beneficial.

“Other buildings in England or Sweden very often have a rigid solid wall structure, and support only mono-functional typologies. We
on the other hand have developed a flexible system which achieves the standard of a passive house,” said Architect Univ. Prof. DI Rüdiger Lainer of RLP.

Architecture
In the high-rise building in Aspern’s Urban Lakeside, the use of wood provides a sensual experience. Wood in it’s truest sense forms an appreciable part of the spatial atmosphere that will contribute 
to the well being of the users. For users and pedestrians alike, the wooden skyscraper is a physical 
and emotive part of everyday life in the city district. The prefabricated external wall modules permit a sculptural and richly varied facade design. The variations on the basic architectural theme of open and closed area offer both open views and intimacy. These variations are accentuated rhythmically and are connected by a facade texture to enrich the ambience within Vienna’s urban lakeside.

Building with wood
The use of wood for modern high-rise structures is not unprecedented, although the HoHo tower will be
the world’s tallest by a considerable margin. The Forte Development, a 10-storey residential complex in Melbourne, Australia, was completed in 2013 and was hailed as the tallest of its type. The 14-storey ‘Trehus’ tower in Bergen, Norway, then surpassed 
it last year. However, the tallest wooden building in the world is not a modern skyscraper, but the 67-meter- tall Sakyamuni Pagoda in China’s Shanxi province. Built in 1056, it has withstood numerous earthquakes over the years and stands the equivalent of about 20 storeys.

The project has, along with
 other high-rise buildings in Vienna, attracted concerns from politicians, who have described its height as ‘exorbitant’ and complained they were not being filled. However Katrina Riedl, spokeswoman for the ÖVP, the Austrian People’s party, defended
the latest project. “Vienna is not
 a skyscraper city, but innovation 
is part of our city and why not try 
new things,” she said. As such, the developers expect preparations for construction to begin in late autumn this year.

Latest Magazine Edition