## 3 Methodology for Evaluating the Effectiveness of Rock Fall Protections
### Analysis of the Effectiveness of the Protection Measures
#### 3.2.2 Evaluation of the Actual Performance Capacity  
In order to help in defining quantitative values for \(\mathrm{r_{n}}\), \(\mathrm{e_{n}}\), and \(\mathrm{t_{n}}\) according to the qualitative degree of severity assigned to the corresponding factor \(\mathrm{n}\), a class of values constituting a sub-range of the interval (0,1) can be assigned to each degree of severity, e.g.,:  
* Very low 1.00-0.95
* Low 0.95-0.90
* Moderate 0.90-0.80
* High 0.80-0.70
* Very high <0.70  
Specific quantitative values representing the severity appreciated on site for the factor considered can then be appropriately picked within the corresponding sub-range, as a function of the particular situation studied, to establish, at best, the corresponding penalty coefficient. The most relevant and as exhaustive criteria as possible for the definition and validation of the values of each penalty coefficient (as well as the boundaries of each sub-range for their preliminary evaluation) are currently in the course of development. Next, once determined for all factors involved, the relevant penalty coefficients values (r\({}_{\text{n}}\) or e\({}_{\text{n}}\) and/or t\({}_{\text{n}}\)) are applied to the corresponding parameters R\({}_{\text{opt,(i)}}\), E\({}_{\text{opt}}\) and D\({}_{\text{opt}}\), as briefly mentioned in the previous section. This step allows us to compute the possible total loss of effectiveness of the inspected protection and define what will hereafter be referred to as the \"reduced\" (actual) performance capacity of the protection: R\({}_{\text{red,(i)}}\), for protections at the source area, or (E\({}_{\text{red}}\), D\({}_{\text{red}}\)) for protections in the propagation zone. In particular, two sub-steps of analysis are planned to accomplish this evaluation, as follows. Effective Performance Capacity: Condition 0  
In this first sub-step of evaluation, only the effects of factors belonging to Group 0 are studied. The idea is to assess whether the conditions of operation of a protection changed only due to potential issues in the original design of the measure (either regarding the interaction with the surrounding environment or some technical/structural features). The penalty coefficients describing the j factors affecting the behaviour of the protection are applied to the parameters representing its performance capacity in \"optimal\" conditions (nominal capacity), so that this capacity will be lowered down to \"effective\". This step of evaluation is defined as a \"Condition 0\" analysis:  
\[\text{R}_{\text{eff,(i)}}=\text{R}_{\text{opt,(i)}}\cdot\prod_{\text{j}}\text {r}_{\text{0,(i)}} \tag{6}\]  
\[\text{E}_{\text{eff}}=\text{E}_{\text{opt}}\cdot\prod_{\text{j}}\text{e}_{ \text{0j}} \tag{7}\]  
\[\text{D}_{\text{eff}}=\text{D}_{\text{opt}}\cdot\prod_{\text{j}}\text{t}_{ \text{0j}} \tag{8}\]  
Equation (6) is used for measures at the source areas; Equations (7) and (8) for measures in the propagation zone (Equation (8) only for ditches and berms). In these equations, R\({}_{\text{eff,(i)}}\), E\({}_{\text{eff}}\) and D\({}_{\text{eff}}\) express the effective performance capacity the protection measures have, in terms of resistance to the release of blocks R, energy E and height D at their locations, while R\({}_{\text{opt,(i)}}\), E\({}_{\text{opt}}\) and D\({}_{\text{opt}}\) describe the optimal performance capacity of the protections in terms of the same parameters. The coefficients r\({}_{\text{0j,(i)}}\), e\({}_{\text{0j}}\) and t\({}_{\text{0j}}\) represent the effects of factor j of Group 0 on R, E and D, respectively, and 0 refers to the \"Condition 0\" analysis. Reduced Performance Capacity: Conditions 1 to 4  
The second sub-step of evaluation is focused, on the other hand, only on the effects of factors in Group N, which are often responsible for the most significant losses in the performance of a protection measure.