Case Study: Flying CLT stairs
According to architectural design for the project KF School, stairs should be made from CLT (cross laminated timber) and their main design characteristic is unique “supportless” design. Relying on the knowledge and experience our team, analyzed this problem and proposed four solutions that satisfied the flying stairs concept.
CUSTOM STEEL PARTS AND POST TENSION CABLES
This is the most specific solution. With this solution, the given architectural design and the look of the stairs is fully achieved. Stair landings don’t have any vertical supports. They are only connected to the stairs with a rigid connection, thus making a stable structural system.
The rigid connection of the stairs and landing is secured with a custom steel element that is glued in the both elements. Additionally, to reduce forces on this element, the system is tightened with post tension cables.
The design of such a system may take a lot of time and it will be necessary to test the rigidity of connection like this. A great advantage of this connection is a unique final look, but because of using many customized elements the cost is expected to be much higher.
WITH ONE GL COLUMN BETWEEN CLT STAIRS
We went for the solution with one timber column between stairs ( it was the most cost efficient solution). One column, which is only additional vertical support, is placed between stairs next to the landing.
Landing is made out of steel platform and CLT panel over it. This steel platform Is from one side connected to the wall of the building and with a column in the middle of the one edge.
Connection with the wall is made along the complete edge of the landing and connection with the column is made from two sides of the column.
Stairs are simply supported on landings and bridges over atrium.