# An Integral Fuzzy Model to Evaluate Slab and Beam Bridges with a Preventive Approach
## 3 Methodology
### Second Phase: Fuzzy Evaluation Model
#### 3.3.1 Evaluation Process  
The evaluation process is carried out in two stages. First, a modular evaluation is conducted, where the condition of individual bridge elements is analyzed based on their  
Figure 4: Access properties membership functions.  
Figure 5: Connection properties membership functions.  
Figure 6: Structure condition membership functions.  
Figure 7: Attention urgency membership functions.  
properties. The condition of these elements is determined by the deterioration present in their properties. Next, the evaluation of the components' condition is carried out, based on the state of the elements that comprise them and taking into account the influence of each element on the component's performance. As a result of the modular evaluation, the model provides four ratings that describe the condition of each module that makes up the bridge. The interpretation of each one is as follows:  
* Adequate. An adequate condition of an individual element indicates that it is in its optimal condition or with practically imperceptible deterioration. Hence, we apply periodic maintenance actions to maintain their aspect and avoid accumulations of garbage or humidity.
* Sufficient. A sufficient condition on an individual element indicates that it is in good condition with some noticeable deterioration. In this case, neither resistance nor functionality is compromised. However, its aspect could be compromised. On the other hand, the deterioration that occurs, being observable, requires maintenance since the element is exposed to external conditions that affect the materials with which it is made. In this condition, preventive maintenance actions have to be carried out, accompanied by periodic maintenance actions.
* Deficient. A poor condition of an individual element indicates that it is in a state where its functionality or resistance is compromised. In this state, the deterioration is completely observable, and the state of this element is probably damaging the nearby elements. This condition is likely to compromise the bridge's performance, and the safety of users may be compromised. In this condition, deterioration begins to progress very rapidly, and it is highly probable that corrective, preventive, and periodic maintenance actions must be carried out in a short-term period.
* Risky. A risky state on an individual element indicates that it is failing. Here, the performance of the element is nearly zero, and the safety of the users, the structure itself, or both is completely compromised. It is crucial to execute corrective maintenance actions to restore safety to the structure and prevent compromising users or nearby elements.  
The modular assessment is based on the catalog described in Table 3. Each module is organized according to its function and interaction with other elements. The modular structure not only allows for establishing relationships between elements but also facilitates the adaptation of the model to other types of bridges, enabling the inclusion or exclusion of elements as needed. In this way, if a bridge has additional elements, these can be added to the corresponding module. Conversely, if an element is not present, its omission does not affect the model's results, nor does it require modifying the existing input parameters. However, when new modules are incorporated, new input sets need to be defined in the fuzzy model, along with their respective membership functions. This also entails generating new inference rules that allow representing all possible deterioration scenarios associated with these new elements.