Important criteria for designing waffle slabs



The double-sided performance of the waffle roofs makes the roofs better able to cushion the long openings. The numerous technical and economic benefits of modern waffle roofs have dramatically increased the use of these ceilings throughout the country. But benefiting from multiple advantages of these roofs in the first place depends on the correct design of the structure. Since the buildings constructed with a waffle roof are generally semi-long or tall openings, their design is more sensitive and requires more designer skills.

The first step in designing buildings with a Waffle roof system is to select the appropriate seismic system for the building. Typically, the factors influencing this selection can be the height of the structure, the user, the degree of importance, the type of soil, the seismic zone, the architectural excerpts and the area of ​​the infrastructure. The correct design and correcting of the vibrating septic system is of great importance according to the regulations of the regulations in order to achieve the expected strength and strength of the regulation.

The second step in designing buildings with a waffle roof system is to design and properly fit the ceiling system. Design of waffle roofs for gravity and seismic loads with safe software. The controls needed to design a waffle roof can be categorized as follows.

1- Controlling the alignment and center distance to the center of the joists and the upper slab according to the rules of the regulations and executive constraints:

The design of the waffle roofs is generally based on assumptions about the system of orthogonal concrete pylons and a top slab. The national regulations of the building consider geometric constraints for the minimum width of the joists, the free distance between the joists and the upper slab thickness, which should be controlled and applied by the structural designer.

2- Control of the thickness of the ceiling based on short and long term criteria:

The most important determinants of the thickness of the waffle roof are the ceiling height control. The rise of the waffle roofs should not exceed the values ​​of the regulations in the short and long term, in order to be acceptable both to the users in terms of psychological point of view and to the detriment of unauthorized elements.

3- Flexible roof design and correct dithilength of flexural reinforcement:

The waffle roofs should be designed for gravity and seismic bending anchors. It was also necessary to consider the minimum dimensions of the longitudinal reinforcement, as well as the dimensions of the reinforcement corresponding to the assumed ductility in the design.

4. Uncontrolled cutting of the roof at critical points:

One-sided cutting should be carried out at critical points based on the regulations of the regulations and the adequacy of the roof in tolerance to one-sided cutting.

5. Control of double-sided cutting and design of shear warheads in required areas:

One of the critical controls in the waffle roofs is the control of the punch cut in the area of ​​the column head. This control is more critical in cases where the slab is relying directly on the pillar and should be installed by the designer and the shear reinforcement needed to control the punch cut in the columns.

6. Design of the caretakers and cords on the ceiling:

One of the most important steps in designing the ceilings is the proper design of the calctor and kord elements to safely transport and transfer the seismic loads to the portable elements. The lack of proper design of this section leads to a defect in the load transfer path in the earthquake, resulting in a lack of access to the expected behavior of the regulation.

7. Control and reinforcement around the ceiling openings:

The location of the ceiling openings and the opening dimensions should be taken into account by the designer of the shear and flexural reinforcement needed to prevent cracking and bending failure and punch around the opening.

8. Rotational vibration control:

In general, the vibration of the roofs should not exceed the perceived level by the human being, in order to provide comfort to the operators. One of the requirements of the regulation is the design of waffles roof vibration control, which, if properly designed and satisfy the rules of the regulations, these roofs will be vibration free.

9. Control of surface dytylling to achieve expected expected plasticity.

In order to allow the roof to adhere to the level of ductility it has in designing the bearings, it is necessary to comply with the provisions of the regulations corresponding to those levels of ductility in the design and roof dithylation.