HOLEDECK against earthquakes
Structures that must resist seismic loads have to be designed and conceived under this premise from the very beginning of the process. This fact is so relevant that can (and should) affect in a general way the selection of the structural system.
In general, every seismic-resistant building consists of three types of elements:
- Primary elements, which resist horizontal loads produced by the seism.
- Secondary elements, with no responsibility in the event of an earthquake.
- Rigid diaphragm, whose purpose is to carry horizontal loads from whatever spot on the storey to a primary element.
HOLEDECK can take part in all those three categories:
- In low seismic places, a system with HOLEDECK waffle slab and solid heads supported by columns can work as a primary element. Whilst the topping would act as a diaphragm.. Thanks to its smaller mass , in comparison to other two-way systems, it diminishes the significance of seismic loads.
- In high seismic places, HOLEDECK solutions, both one and two-way, would span the panels left within the primary elements (be it frames or shear walls) and behave as a diaphragm, being more efficient when performing that function because of its bigger radius of gyration and smaller mass.
Through some study cases, it will be explained how HOLEDECK solutions provide a top-up, not only from a structural perspective, but also from the point of view of design, flexibility of usage and economy of means. The walls are identified in red, seismic resistant beams in dark grey and non seismic resistant beams in light grey.
Detached residential building 12 m deep and 20 m wide (Example 01)
Place shear walls or stretched columns in the corners with an L shape, Perimeter beams with seismic function will cover the span between them. The interior beams needed to create the staircase and elevator hole, which would be secondary elements, should be supported by columns so as to avoid trimmer beams. Between the beams, we would have 8×12 m, panels spanned easily by Ho45. With this solution, it is possible to have two flats of 90 m² per storey with a complete freedom to place the partitions and the rooms.
Office tower. 24×24 m (Example 02)
The typical distribution of a central core with walls in one direction could be complemented with two symmetric perimeter walls in a perpendicular direction. In the direction of the exterior walls, primary beams would be in the perimeter too. In the perpendicular direction, they would be interior. The rest of the grid would be completed with secondary beams. The floor is made with a Ho30 slab spanning 8×8 m. This solution is lighter than its equivalent in other traditional systems, which is relevant for high buildings.
Commercial/industrial building 18 m deep and 12 m wide bays (Example 03)
Walls would be placed in the corners and a column separating the bays. The primary deep beams would be placed in the perimeter, and from column to column, spanning the nave, the secondary ones. Resulting 12 m spans might be covered with one-way 60 cm deep HoXL. This way, 200 m² premises/warehouses without any column inside and with total freedom to place the installations without any room height loss are designed.
Building between party walls in old town (Example 04)
The concrete walls would be placed in the boundaries of the plot and two shorter perpendicular walls inside. From boundary wall to boundary wall, primary beams would be supported, by the inner walls, placing secondary beams, in both façades. 12×8 m panels to span unidirectionally with HoXL are achieved. It is possible to partition the lower floor (commercial) and the upper floors (housing or hotel, i.e.) , in completely different ways with no column interference.
In short, in seismic-resistant buildings, HOLEDECK slab systems provide stiffness to diaphragms, lightness as a constructive element and versatility in the solutions.