# SimEx: A Tool for the Rapid Evaluation of the Effects of Explosions
## 3 Example of Application: Facade of a Building under Blast Loading
### SDOF System Integration and CW-S Damage Diagrams  
Once the user sets the explosive charge and the properties of the equivalent SDOF system, SimEx is ready to integrate the resulting mathematical problem. Figure 2 shows the results for the case of a HEB 340 profile with a 5 m span between pillars. The main results are the maximum deflection, \(x_{\text{max}}\), the ductility ratio, \(\mu\), and the maximum rotation angle, \(\theta\). The two latter parameters are used as indicators to quantify the component damage levels [15]. Assuming that the Level of Protection (LOP) required is very low, in case of a hot rolled compact steel shape for the columns, according to [15], the allowable component damage is heavy (response between B2-B3).  
Figure 11: Metal beam calculation assistant showing results for a HEB 340 pillar with a length of 3 m and a spacing between pillars of 5 m. Note that, even though a HEB 350 is requested, which is not included in the norm, the assistant corrects down to the nearest normalized value, HEB 340.  
Figure 12: Reinforced concrete beam calculation assistant showing results for a pillar of 45 \(\times\) 45 cm\({}^{2}\) with a length of 3 m and a spacing between pillars of 5 m. The pillar is reinforced using 5 A36 steel reinforcement bars of 22.5 mm of diameter per side spaced apart 37 cm.  
For fixed values of the structural parameters, a parametric sweep can be carried out in CW-S space to obtain damage diagrams such as the ones shown in Figure 13. To this end, it is enough to indicate in the assistant the charge weight and standoff distance ranges to be analyzed and the number of intervals to be used for each parameter. In addition, the desired damage level criteria must be indicated to separate the zones. Figure 2 shows characteristic values of \(\mu\) and \(\theta\) for metallic elements, although other values could be selected from [15] for other structural elements and materials. Note that CW-S damage diagrams are presented both in linear and log-log scales.  
As can be seen, the CW-S damage diagrams shown in Figure 13 include three points corresponding to the three cases considered in Table 4. As the three scaled distances are almost equal, then the damage levels are also very similar, although differences in real distances and incidence angles make them grow from superficial-moderate (B1) to (almost) moderate-heavy (B2) for increasing charge weights and standoff distances. According to the PDC-TR 06-08 [15], a superficial damage level implies \"no visible permanent damage\", whereas a moderate damage level implies \"some permanent deflection\" that generally can be repaired. By way of contrast, a heavy damage is associated with \"significant permanent deflections\" that cause the component to be unrepairable.  
To summarize the results obtained in the different case studies, Table 5 reports the incident blast load parameters and the corresponding component damage indicators per floor for Cases 1, 2, and 3. The reference case (Level 1, Case 2) and the worst-case scenario (Level 2, Case 3) are both highlighted for clarity. As can be seen, damage levels are significantly higher in the upper floor (Level 2) as a result of the lowest rigidity imposed by the cantilever boundary condition at the roof top, resulting in heavy damage levels for cases 2 and 3.