Issue 46

F. Stochino et alii, Frattura ed Integrità Strutturale, 46 (2018) 216-225; DOI: 10.3221/IGF-ESIS.46.20 217 The main objectives of the bridges infrastructure networks maintenance strategies, are to ensure, in probabilistic terms, the safety of the individual citizen and the effectiveness of the transport system. In addition, in case of natural disasters (floods, earthquakes, etc.) or acts of terrorism, a good ability of infrastructural network to provide alternative routes (resilience), with primary focus on strategic activities (civil defense, hospitals, energy supply, waste disposal, etc.) see [4-6], is expected. In recent years, the importance of Bridge Management System (BMS) has been increasing. BMS is the set of inspection, investigation, maintenance, repair of a group of bridges or viaducts, organized according to priority, with the support of computer databases and algorithms officers. In most of cases, the condition of a structure is assessed by qualitative judgments. Figure 1 : Bridge Management System In a schematic way, see Fig. 1, it can be said that a BMS is composed of: - Inventory of bridges network; - Data analysis capabilities on the basis of deterioration models; - Cost models; - Optimization programs, which are based on previous assessments, help in planning characteristics and schedule of the retrofitting. Therefore, A BMS can be seen as a tool that can: o Assess the condition and give an overview about the status of the structures; o Formulate maintenance programs within predetermined cost limits and plan consequent actions; o Schedule requests and fund appropriations. The main goal is to obtain a representative picture of each structure that will allow making adequate maintenance work or to underline the need for further in-depth investigation [7]. In order to prioritize maintenance investments bridge rating strategy is adopted in BMS. Usually, the rates of bridges can be compared at project or network level and can consider both serviceability and relevance. Different methods can be found in the literature: an Integrated Bridge Index (IBI) is presented in [8]. It takes into account the vulnerability risk and strategic importance of each net component. Visual inspection, experts survey and regression analysis has been adopted for calibration. An effective approach for fast and automatic evaluation of bridges robustness and resilience is presented in [9], while multi-attribute utility theory (MUAT) is implemented in bridges ranking strategy in [10]. Also fuzzy logic has been adopted in this context with some interesting results, see [11] and [12].