HoHo Vienna is one of the tallest wooden buildings in the world and a lighthouse project for sustainable timber construction. Thanks to the level of thermal insulation, resource conservation, energy efficiency and sound insulation, it has been awarded with the certification LEED Gold and ÖGNB gold from the Austrian Society for Sustainable Buildings.
The HoHo Vienna, designed by the architectural firm Rüdiger Lainer and Partner, is going to become the landmark of one of the largest urban development projects in Europe, the Seestadt Aspern. The overall complex accounts for around 19,500 m² and includes a hotel as well as restaurants, offices, apartments and a fitness area. The main complex is composed by the main tower, 84 m high tower with 24 floors, and two further towers with 15 and 9 floors structurally connected in order to enhance the robustness of the building.
Considering the building size, material and complexity, the fire protection of the structure represents the main challenge for the designers. The final solution consists on a hybrid structure with a concrete core where the staircase, lift and technical shafts are located. The concrete structure is coupled with a modular wooden construction system, based on four prefabricated serial components: columns, main beams, deck slabs and facade elements. The high level of modularity of the elements allowed to speed-up the construction time, no more slowed down by negative weather conditions.
The structural engineers from RWT Plus developed a system node especially for Hoho Vienna, which positively joins the prefabricated elements - wood-concrete composite ceilings, wooden columns, beams and wall elements.
74% of the building is made by wood and, thanks to this approach, the construction saved 2,800 t CO2 equivalent compared to a conventionally constructed building of the same type and size. In addition, the CO2 balance is also improved by the short transport routes, because the wood comes exclusively from sustainably managed, native forests; one of the prerequisites for LEED certification in gold.
The 6,000 m² of insulating glazing achieves very high performances, with a thermal transmittance of 0.5 W / m²K. The thermal transmittance for the entire window is 0.78 W/m2 K. The tight edge bond, in conjunction with the flexible material based on silicone foam, also reduces the stress caused by pumping effects and the high wind loads at a height of 84 m. This would avoid stress cracks in the seal. The wall elements delivered just-in-time were hoisted and assembled on site by crane. The U-value of 0.182 W/m² K of the opaque wall elements reflects the good thermal insulation properties of the building.
For further details relating to HoHo Vienna, please consult the HoHo Vienna website at http://www.hoho-wien.at.