## 4 Finite Elements Model Details  
As commented previously, before defining the experimental program, it was necessary to elaborate a numerical model to predict the structural behavior and resistance expected. The results obtained gave criteria for the instrumental phase, helping to define the location and needing some of the measures instruments. The numerical model (see Figure 23a) was developed with the help of the SAP 2000 software [35], taking into account the following considerations:  
* Steel profiles were modelled as frame elements. Nominal values were used on the cold-formed steel to define its properties: elasticity unit (E\({}_{\text{s}}\) = 2.074 \(\times\) 10\({}^{6}\) kg/cm\({}^{2}\)), yield strength (F\({}_{\text{y}}\) = 2310 kg/cm\({}^{2}\)), [PERSON]'s ratio (\(\mu\) = 0.30), volumetric weight (\(\gamma_{\text{s}}\)= 7.849 kg/cm\({}^{3}\)) being the physical properties of each profile; PA (d = 10.00 cm, b = 3.20 cm, t = 0.80 cm), PE (d = 9.84 cm, b = 5.00 cm, t = 0.80 cm);  
Figure 22: Cyclic response: (**a**) Load-displacement relationships on the different load cycles; (**b**) Involving curves of load displacement.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Load** & \(\Delta_{\text{oi}}\) & \(P_{\text{ei}}\) & \(\Delta_{\text{i}}\) & \(P_{\text{i}}\) & \(K_{\text{i}}\) & **CJP** &
\begin{tabular}{  
* Fibrocement sheets were modelled as shell elements, combining the plate and membrane behavior. Nominal values given by the manufacturer were used: elasticity unit (E\({}_{\mathrm{fc}}\) = 33,130 kg/cm\({}^{2}\)), Poisson's ratio (\(\mu\) = 0.20), volumetric weight (\(\gamma_{\mathrm{fc}}\) = 1.100 kg/cm\({}^{3}\)), being the properties of this section: the thickness for the plate behavior (t\({}_{\mathrm{pl}}\) = 1.40 cm), and the thickness for the membrane behavior (t\({}_{\mathrm{m}}\) = 1.40 cm);
* Connections between the steel sheets were considered as pinned connection and they were only retrained to displacements and not to rotations;
* Screwed connections between profiles and panels were modelled as rigid links, to the profile's centroidal axis to the sheet's centroidal axis. When there was not relative displacements or deformations in this connection, the links had the goal of applying similar actions as the interface of the two structural component screws did;
* Wind load was considered and applied on a uniform load of 38.4 kg/m\({}^{2}\) to the shell items of the frontal wall.  
The most important results obtained with the FEM model (Figure 24a) are shown following.  
Figure 23: FEM model: (**a**) SAP 2000 FEM model of the experimental specimen; (**b**) Deformation on the central profile PE of the FEM model.  
* The higher experimented deformation shown by the system was on the center of the frontal wall, on its upper extreme, resulting to be 0.897 cm;
* The stiffness of the system, defined in this particular case as a total applied load (571.55 kg) and the higher experimented deformation by the system being 637 kg/cm;
* The profiles PE rotate from the base and deform on the same way as the steel beam. Figure 24b shows the deformation scaled from the central profile PE.
* The upper profile PA suffers nearly the same displacements on the length of it, and its deformations, even if they are very little, are similar to the experimented by the standing beam. Figure 24a shows this deformation;
* Figure 24b shows the variation of bending moments on the direction that they apply the load to the profiles PE, that is, the horizontal direction.