Design load analysis
The design load analysis is carried out by means of a 3D spatial analysis using stiffness matrix methods, which contains all the elements that define the structure: columns, reinforced concrete shear walls, walls, beams, and slabs.
The deformation compatibility of all nodes is established, considering 6 degrees of freedom, and the non-deformability hypothesis of the plane of each floor is created to simulate the rigid behaviour of the floor slab, preventing relative displacements between nodes of the slab (rigid diaphragm). Therefore, each floor can only rotate and move as a whole (3 degrees of freedom).
The consideration of rigid diaphragm for each independent area of a floor is preserved even if beams, not floor slabs, are defined on the floor, except for unconnected beams that users disconnect from the rigid diaphragm and except for walls that are not in contact with floor slabs (from v.2012.a onwards). More information can be found on the "Rigid diaphragm at floor level in CYPECAD" web page.
When there are independent areas on the same floor, each of these is regarded as a separate part in terms of the non-deformability of that area and shall not be considered as a whole. Therefore, the floors will act as independent non-deformable planes. A non-connected column is considered as an independent area.
For all load states, a static analysis is carried out (except when dynamic actions due to seismic activity are considered, in which case the spectral modal analysis is used) where a linear behaviour of the materials is assumed and, therefore, the first-order analysis, in order to obtain displacements and stresses.
Integrated 3D structures always have 6 degrees of freedom per node. More information on integrated 3D structures.
Stairs also have 6 degrees of freedom and are developed and completed separately. The program determines the reactions on the main structure, which are translated as linear and surface loads (in the case of steps built on the floor) in the dead load and live load loadcases. More information on stairs.
Detailed information on this aspect can be found in the "CYPECAD – Calculations manual”. The manual can be accessed from the main menu of the CYPE programs or from the CYPECAD "Help" drop-down menu.
