The LCT ONE (LifeCycle Tower ONE) is a pioneering structure in many respects. The project is the first eight-storey timber building in Austria. For the first time, a building in timber construction was erected on the high-rise boundary. It also represents the prototype for the timber system construction method developed in the "LifeCycle Tower" research project. The aim of the project was to test the feasibility of the building system and its functionality under real conditions of use. This demonstration project was a central component in achieving international market maturity.
The office space is attached to the stiffening staircase core of the LCT ONE on one hip. Contrary to the proposal in the previous LCT research project to also build the staircase core in wood, the core is made of in-situ concrete. According to the current legal regulations for fire protection, it is currently not possible to produce the core from combustible building materials.
With the test certificate (according to DIN EN 13501) of the fire resistance REI 90 of the wood composite hybrid ceiling, an important requirement of the fire protection authority is met. For this purpose, several HBV elements measuring 2.7 m x 8.1 m – corresponding to the façade grid and the possible room depth – were subjected to a fire test at Pavus in the Czech Republic.
The wood-concrete composite ribbed ceiling is the real key to building upwards. This makes it possible to consistently separate the respective projectiles by a non-combustible layer. The wooden beams are placed in the steel formwork of 8.1 by 2.7 metres, the distances between them are formed and concreted using the grouting method. The high degree of prefabrication significantly simplifies the construction process. The ceiling elements can be worked much more precisely industrially, there are no curing times on the construction site and the craftsmen specify only five minutes for the installation of a ceiling element.
The shear bond between concrete and glulam beams is not created by means of complicated connectors, but by means of screws and shear notches. The concrete lintel girders are statically essential for the transmission of the enormous forces from the façade supports. The end grain of the double columns stands directly on the concrete, the connecting mandrel is cast into the precast element on the construction site. This lintel girder also enables the separation of the structure in the column plane on each floor, which is necessary in terms of fire protection, and the introduction of the loads from the ceiling into the column without loading a wooden component transversely to the grain. Following the course of forces, the columns are assembled according to the actual static requirements.
NGF 1,765 m², GFA 2,319 m²
BRI 8,074 m³
Energy 9 kWh/m²a
Source: Hermann Kaufmann + Partner ZT GmbH
Photos: Norman Radon
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