CYPECAD contains a software tool which allows for a dynamic analysis to be carried out on buildings with seismic loads acting upon them, which includes the effects of the non-structural construction elements used in the façades and partitions of the building, and considers various behavioural models of the building corresponding to different situations or states of these elements.
The façades and partitions of the building are considered as being “non-structural” elements, however, during an earthquake, they do provide stiffness to the structure, hence modifying the distribution and magnitude of the forces caused by the seismic action For example, when there is a non-uniform distribution between floors of the stiffness associated with the partitions, the horizontal forces have a greater impact on the columns belonging to the floors with less stiffness, producing shear forces of a high magnitude in the columns. If these have not been designed accordingly, the forces can cause a fragile fracture, endangering the stability of the building, even leading to its collapse.
This is the case of buildings, whose ground floor is destined to be used as retail precincts, and are, generally, irregularly stiff, causing them to be weaker at that floor. The difference in stiffness is due to the height of that floor usually being higher than that of the other floors, and that, due to the use of the floor, is an open floor. Even if the floor below were to have a similar stiffness to that of those above, during the first instants of the earthquake, the partitions of the lower parts of the building fracture, causing an abrupt change in the stiffness, and therefore, an irregularity similar to that described previously. Hence, the stiffness provided by the different non-structural elements can change during the seismic action, due to the cracks and fractures which appear successively.
This module has been developed by CYPE, with the collaboration of the Centro Internacional de Métodos Numéricos en Ingeniería (CIMNE) of the Universidad Politécnica de Cataluña (UPC), financed by the Centro para el Desarrollo Tecnológico Industrial (CDTI) and co-financed by the European Regional Development Fund (ERDF).
There are currently no software tools available on the market for the structural analysis of buildings which integrate the possibility of considering, in a simple manner, the façades and partitions, even though it has been proved that they directly affect the stability, stiffness and safety of the building during an earthquake. Since this CYPECAD module does integrate them, keeping the computation periods within an admissible period, their integration in the building projects will increase their quality and the safety of their occupants, allowing for unfortunate losses, both material and human, to be avoided after an earthquake.
More information can be found on the Interaction of the structure with the construction elements webpage.
