Background: Timber construction on the rise
In recent years there has been a concerted race by the timber industry to construct ever-taller timber buildings. New high-rise projects as tall as 100, 200 or even 300 metres are being built on an almost monthly basis. Currently, the tallest timber structure, called HoHo Wien, is being constructed in Vienna's new district, Seestadt Aspern (fig. 2). Architects RLP Rüdiger Lainer + Partners designed the high-rise, which will reach an impressive height of 84 metres. The three wings — 11, 16 and 24 storeys — of the new-build will accommodate almost 20,000 m² of rental floor area for office and retail use. The architects and investors are aiming at a TQB (Total Quality Building) certification with their 65 million Euro, hybrid timber/concrete structure. The ground floor is built completely in concrete and the multi-storey tower above has concrete lift cores and central, wedge-shaped circulation zones. The office floors connected to the outside of these cores, consist primarily of four prefabricated elements (fig. 3). Laminated timber columns on the facade support continuous precast concrete beams, which in turn carry the load of the timber/concrete composite floors, made from 140-160-mm laminated timber and 120-mm reinforced concrete. The high-rise facade will consist of CLT panels on the interior, an intermediate insulation layer, a ventilated rainscreen of wood-fibre and reinforced concrete elements on the outside.
