PSI - Issue 44

Fabrizio Paolacci et al. / Procedia Structural Integrity 44 (2023) 697–704 Fabrizio Paolacci et al. / Structural Integrity Procedia 00 (2022) 000–000

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to model the frame pier and concentrated mass has been used to take in account the desk, as shown in Fig 5a. Furthermore, plastic fiber hinges have been attributed to the section taking in account a Kent & Park model for the concrete behaviour and a Menegotto Pinto model for the steel, in order to study the plastic behaviour of the pier, as shown in Fig. 5b. In the present study, the limit state of significant damage (SLV) with a probability of exceedance in 50 year of 10% is considered. Following the steps described in the previous section, the pushover capacity curve of the bridge is carried out (blue curve of Fig. 4a) and the relative bilinear curve (red curve of Fig.4a) is obtained.

Fig. 5 a) FEM of the frame pier b)Fiber hinges model

A value of D u =0.02m is evaluated from the capacity curve as described above. Furthermore, the value of D max has been evaluated through Eq.4 and, considering a value of dispersion of 0.2 for both the demand and the limit state, the fragility curve relative to the limit state considered is carried out using Eq. 3 and shown in Fig.3a. The value of IM,50% = 1.27g is carried out from fragility curve, and its probability of occurrence λ ( 1.27g) = 1.7 ∗ 10 −3 is evaluated from the hazard curve. As last step, from the hazard curve of the site, depicted in Fig. 3b, the linear curve that approximate the hazard curve in the region of interest is evaluated and a slope value of = 2.6 is obtained. Finally, the mean annual frequency of exceedance λ ( LS ) is obtained from Eq. 2 that show a value of 2.22 ∙ 10 −3 . 5. Conclusions In the present paper the structure of MLAZIO project and its current progress are illustrated and a new methodology for the seismic risk assessment is shown. The project, a collaboration between the Department of Engineering of Roma Tre University and the Lazio Region, aims at providing the methodological bases for the institution of a Lazio Region BMS, for the classification, the management, the evaluation and the monitoring of bridges safety. The multi-level approach suggested by the Italian guidelines (MIT 17/04/2020) is adopted, enriched with novel tools, such as satellite monitoring, BIM and GIS, and expeditious methods for the quantitative evaluation of both static and seismic risks. To date levels 0-to-2 have been developed, including the design of a database for bridges census – level 0 – and the development of procedures for both the evaluation of the conservation state of bridges (synthetically represented by a defect level) – level 1 – and the assignment of an attention class – level 2. Furthermore, a new methodology for the quantitative and expeditious seismic risk assessment is herein proposed in order to integrate the Level 3 prescription of the guidelines. The seismic risk indexes of the bridges of the Lazio region can be quickly evaluate starting from the hazard curve of the site and by means a simplified FEM model. A pushover analysis of the structure is herein proposed to evaluate the capacity of the bridge and, using a simplified