– Lakhta Center has the tower that falls in the category of the so-called twisted skyscrapers. How is this principle implemented in your project?
– If we think about all of the twisted skyscrapers, middle-eastern ones in particular, I can say that our building is unique in terms of the twist. I will explain: each typical floor consists of five petals that are twisted and have their own axes. The axes in their turn twist around the central axis of the building, gradually moving towards the center. This is a complicated geometry that has no equivalents in the world.
As a results, during construction process the floor slab turns by 0,82 degrees in relation to the building’s axis. That means that each floor has a slight turning angle, which creates the twisting effect up to the top of the building.
Generally, there is nothing new about twisting, we’ve known such projects for a long time. However, there a lot of questions that arise during the construction of twisted buildings. They are connected with the natural gravitation forces and have to be solved at the early design and construction stages.
Let’s say, that before taking off the temporary fastening, we need to provide rigid attachment of the structures to the core. In other words, to perform the in-situ concreting by creating a horizontal rigid diaphragm. This allows minimizing the torsional effect, i.e. movement of the horizontal slabs around the core. It is necessary to consider also that the concrete is a creeping material and the torsion will continue, but not at the same extent. This is only of the examples of the processes that we need to control and adjust during construction.
– Does the difficult geometry imply the extraordinary approaches to the steel structures erection?
– The building itself is irregular and changes both horizontally and vertically. Consequently, each element of the complicated geometry is programmed to do so. This means that each structural steel element is singular and does not repeat any other one. This refers both to columns and beams. The complexity lies in such analysis of the steel structures parameters that allows avoiding the adjustment of these particular elements in shop or on site.
It is a standard production process, if all these peculiarities are analyzed in advance and are submitted to production. In fact, we create a hand-made product. We consider the sequence in advance. If the beam for floor 15 arrives to the construction site when floor 13 is being installed, it waits for its turn.
– When is the last technical floor is expected to be installed?
– Next year. The last technical floor will be finished by summer, at the same time the spire installation operations will start.
Source: http://lakhta.centerback to news list
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