Residential building, Czech Republic
The building is designed to be a hotel with underground parking and a commercial part on the ground floor. Load-bearing parts of the structure are completely from the concrete. It includes 12 ground floors and 3 underground floors. From a structural point of view, it is a both-direction wall load-bearing system. In the underground part and also in the commercial part the LB system is more skeleton system consisting mainly of columns that locally support the ceiling slab. The underground part of the structure is designed to be waterproof as a ,, white tank“. The whole structure is supported by long drilled piles in combination with a relatively thick foundation slab which is designed to carry inner forces caused by interaction with subsoil after settling of piles. Because the building is surrounded by existing buildings, there is also designed shoring of the foundation pit with its consequences to the design mentioned later.
As the building looks relatively simple from the outside, there were many tasks to solve. The especially hard part of our design was (more than in another project) transferring of all loading from above the ground floors to the underground floors, because of big differences between the plan of ground floors and underground floors. This results in many problematic parts in structure. Another very important part of the structure is deep beams, which are designed through 2 floors, where the structural wall system is changing into skeleton one.
All the information described above led into so-called ,,D zones“ which are the riskiest parts of the concrete structure. So we’ve used IDEA STATICA mainly for two reasons. On one hand to ensure ourselves in D zones, that they are designed well, on the other hand to optimize amount of reinforcement in deep beams, which are in this structure in considerable big volume.
For example, we’ve used IDEA for the contact between the perimeter underground wall, foundation slab, and pile. The main problem here was, that piles in many places couldn’t be placed centrically below walls, because they needed to be placed some proper distance far from the shoring of the foundation pit. Big advantage in designing by IDEA was, that we were able to check the head of the pile very deeply and precisely and set it according to it thickness of the foundation slab. Without it, we used probably much higher rib around all perimeter of the slab to be empirically sure, that vertical force will spread into all areas of the pile.
Another example was a zone where the column ends in the foundation slab in the space between two piles. This situation is common when the single LB capacity of the pile is not enough, so we need to get, the group“ of piles what means, for example, two pieces with space equal to the diameter of the pile. So it leads into D zone again, when forces from the column are transferred into the piles through pressed diagonal with tensile forces developed.
And another two examples were the deep beams mentioned above and some longer columns/pillars which are loaded very eccentrically in their longer size. Designing deep beams in idea static results in a very good balancing amount of required reinforcement (and check next to the many others our attitudes for designing it). In the case of eccentrically loaded columns, it helps us for a lot not to be so conservative and not to think about vertical force in eccentric distance from the axis of the column only as about bending moment, but more in the way of developing of pressure and tension in the structure.
The author of design is SPACE8 s.r.o. atelier
Building is made in Allplan 3D in ,,BIM“ standard also with reinforcement included. For general structural design we used Scia enginner with some other ,,supportive“ softwares. In this project the key supportive software was IDEA StatiCa, because of many ,,D zones“ of concrete included.
