Peri climbs Canada's curves

Formwork manufacturer Peri's RCS climbing protection panel system is helping work on two curvaceous skyscraper towers progress quickly and safely. The towers are part of Canada's Absolute World City Center in Mississauga.

The inner-city development consists of five apartment and office blocks with heights of up to 170 m. Of note, are the rotations of the two buildings: the southern tower with a varying rotational movement and the northern tower which twists uniformly upwards.

For both buildings, the complete enclosure of the upper floors using the RCS climbing protection panels has ensured the safety of the construction site team resulting in higher productivity.

Due to the different rotations by different degrees at different levels, Peri engineers have developed two climbing methods - with the help of the modular construction system, adapted specifically to suit the respective project requirements and building geometry.

With the 170 m high Absolute Tower South, the elliptically-shaped ground plan rotates by 208° over the course of 56 floors - featuring twists of between 3° and 8° from storey to storey.

In order to ensure safe working conditions, the working area of the three uppermost floors in each case is completely enclosed by means of the RCS climbing protection panel.

During the climbing procedure, the climbing rails are firmly connected to the building by climbing shoes. Compensating for the offset between the individual floors is achieved by a system of steel girders anchored to the slabs: while standard universal RCS climbing rails cantilever up to 2 m beyond the edge of the slab and support the climbing protection panel.

Through the large usable compensation area, the number of levels is minimised where the RCS units have to be re-adjusted due to the rotation of the storeys.

For the floor-by-floor planning of the enclosure, Peri engineers took into consideration all possible obstacles and discontinuities in order to determine an optimal element arrangement and - separate for each floor - the corresponding anchor positions.

Start of construction for the 150 m high, 50­storey North Tower took place a few months later. For this Peri designed a cost-effective climbing variant. As the rotation of the elliptical-shaped floors is a constant 4° in each case here, the RCS protection panel itself uniformly turns in an upward direction.

In addition, the climbing rails are inclined at an angle of 26° to the vertical and connected to the storey slabs by means of RCS system climbing shoes and project-specific modified slab shoes. Likewise, the RCS units are climbed hydraulically - moving with the crane would not be possible because of the inclined climbing track.

That this climbing method is possible with the RCS rail climbing system and is applicable in construction site conditions was proven beforehand by Peri engineers both theoretically and with a physical test set-up.

Mississauga is situated to the west of Toronto in the province of Ontario. With 700,000 inhabitants, it is the sixth-largest city in Canada. Absolute World, with the two dominant towers, provides the city with a completely new, modern face.

The undulating sequence of curves featured on the southern high-rise building has resulted in it being given the nickname of 'Marilyn Monroe' by the local population.