# Comparison of Condition Rating Systems for Bridges in Three European Countries
## 2 Italy
### The New Italian Guidelines for Existing Bridge Assessment  
The new Italian guidelines have been developed with two main objectives in mind: (1) to define common and standard criteria to be used throughout Italy for the risk classification, the structural safety assessment, and the monitoring of existing bridges, including considerations about the transit of exceptional vehicles; and (2) to obtain a unique rating tool to prioritize maintenance works. The guidelines can be used for both roadway and railway bridges, although details are provided mainly for the former.  
The guidelines approach is based on six consequent levels of analysis (from 0 to 5, as reported in Table 1), even if the latter (Level 5) is recommended only for strategic bridges (namely, important in terms of the socio-economic consequences of their collapse and for maintaining communications in emergency situations). The first three levels should be applied to all bridges in the country (with a span length longer than 6 m) and they allow for a bridge classification that accounts for the four risk typologies previously mentioned.  
At the end of these procedures, it is possible to obtain the so-called _Class of Attention_ (_CoA_) for each investigated bridge. Five _CoA_ are defined for five levels of increasing risk: low, medium-low, medium, medium-high, and high.  
Then, for bridges with concerning _CoA_ (mainly medium-high and high), in-depth evaluations must be performed; in detail, for bridges belonging to the high class, Level 4 is mandatory, while for those of medium-high and medium classes, the safety verifications could be performed only if the roadway administrator deemed them necessary. The period for which the satisfaction of safety verifications is required should be taken according to the purpose for which the analysis is intended. In this regard, the concept of \"reference time\" (Tref, the time frame of which the verification is conventionally referred) is introduced. At the end of this time frame, it is generally assumed that the analyses have to be repeated and necessary measures need to be taken to ensure the due level of safety usage (e.g., repair works or load reductions). The safety verifications are conducted following the limit states approach and adopting partial safety factors, and three outcomes can be achieved:  
* Adequate bridge: the bridge performance is compliant with the actual Italian technical code prescriptions. The use of the infrastructure can continue without interruptions and traffic limitations;
* Operative bridge: the safety verifications are fulfilled following the code prescriptions but adopting reduced safety factors on loads and material strengths (considering lower return periods--Tref = 30 years). The bridge can be used during the period considered for the assessment (30 years), then the analyses must be repeated;
* Transistable bridge: the safety verifications are satisfied following the code prescriptions but in a very short time period (5 years). The bridge can be used adopting loads/traffic limitations and for only 5 years, then it must be restored/upgraded/rebuilt.  
For what concerns the monitoring, obviously, all bridges belonging to all classes are subjected to periodic visual inspection over time, also to adjourn their _CoA_. However, for those with high and medium-high _CoA_, instrumental monitoring is recommended, and the installation of a permanent Structural Health Monitoring (SHM) system is recommended for cable-stayed and suspended bridges with high span length longer than 200 m, for pre-stressed RC bridges older than 40 years and with high span lengths longer than 50 m, for pre-stressed RC bridges or steel bridges difficult to visually inspect, for historical and cultural heritage bridges, and for bridges with very high traffic flows and loads.