Bridges are essential for guaranteeing the functioning of transportation systems since their failure can cause serious threats to the safety, well-being and economy of modern communities, especially in emergency conditions. Following recent bridge failures, among which include the Morandi bridge in 2018, specific guidelines on risk classification and management, safety assessment and monitoring of existing bridges have been issued in Italy by the Minister of Infrastructure as a mandatory code. They pay particular attention to the evaluation of the residual life span of critical transportation infrastructure dating back to the 1950s and 1960s of the last century. Being a newly issued tool, the Guidelines need to be applied and tested in order to find possible drawbacks and to point out the main factors influencing their results. Therefore, in this study, after a short description of the Italian Guidelines, pointing out some differences with other approaches adopted worldwide, some advantages and disadvantages are discussed by an application to a bridge stock located in the Basilicata region (Italy). Data needed to apply the Guidelines are gathered by a purposely set up procedure that exploits existing databases on road infrastructure (OpenStreetMap) complemented by additional data retrieved by means of public image repositories (Google Street View). By accounting for the qualitative nature of the risk classification results obtained by applying the lower analysis levels of the Guidelines, a prioritization method is proposed for ranking bridges for higher assessment levels and possible interventions, as well as consequent funds allocation. The application shows that the Guidelines’ approach tends to provide conservative results. In fact, even in case of bridges with low degradation levels, the final risk classification induces actions undertaken for preliminary or detailed assessment; thus, normal operation (with periodic inspections) would not be possible anymore.

Within the 2019–2021 research agreement between the Civil Protection Department (DPC) and the Network of University Laboratories for Earthquake Engineering (ReLUIS), the work package WP4 “Seismic Risk Maps—MARS” is specifically devoted to update the 2018 release of the Italian National Seismic Risk Assessment. To this end, the previously considered models of hazard, exposure and vulnerability will be critically reviewed and updated by taking advantage also from the results deriving from other WPs of the DPC-ReLUIS research project. In the present paper some of the most relevant aspects that are being introduced in the development of the new Italian risk maps have been described and shortly analysed. First, a significant upgrade of the vulnerability model implemented in the new version of the platform used for risk calculation (IRMA) is proposed, where reference to the six EMS-98 classes is made also considering regional vulnerability features. Further, empirical data from observed real damage are integrated with results from numerical simulations (mechanical approach), in particular for reinforced concrete buildings. Finally, some special construction types such as schools, churches and bridges are included in order to provide a more comprehensive view of the national risk.

A wide experimental program on beam-column RC joints carried out in the framework of the DPC-Reluis Project (DPC: Department of Civil Protection, Reluis: Network of University Laboratories of Earthquake Engineering) is presented. All the experimental tests were performed at the Laboratory of Structures of the University of Basilicata, Potenza, Italy. The main objective of the experimental campaign is to study and compare the post-elastic behavior of beam-column joints with different earthquake-resistant design levels, indicating the role of some structural parameters such as the axial load value acting on the column, beam dimensions, and steel type, on the joint performances and failure mechanism. The analyses have mainly been devoted to improving the assessment procedures regarding existing buildings but also to verifying the prediction capability of the capacity models relevant to beam-column joints contained in literature and in the new seismic codes. Following a short description of the experimental methodologies used in other campaigns, the experimental program is presented, providing a detailed description of the specimens and of the testing set-up. This is followed by a report of the main results of the cyclic tests performed on the beam-column specimens that highlight the role played by axial load and seismic design level in determining the failure mechanism and the global response of the joints.

In Italy, most of the residential buildings (77%) were constructed before 1981, when only 25% of the national territory was classified as seismic. Further, the first provisions addressing thermal performance criteria were introduced in 1991, when about 88% of the existing Italian buildings had already been realized. Therefore, the Italian building stock is characterized by a large deficit in terms of both seismic capacity and thermal insulation. The large number of buildings having inadequate performance, both seismic and thermal, calls for rehabilitation interventions that are based on an integrated and sustainability-oriented approach. In the paper, the influence on seismic performance deriving from some retrofitting techniques, generally adopted to enhance the thermal performance of infill walls, has been evaluated. A common residential RC building representative of existing buildings designed only for vertical loads has been studied. The seismic performances have been evaluated through Incremental Dynamic Analyses (IDA). A first comparison is related to a thermal retrofitting intervention made by replacing the existing masonry infill walls with new elements that are able to ensure an adequate thermal protection. Further, a retrofitting intervention based on the “double skin” technique, where new infilled RC frames are added and connected to the existing ones, has been investigated in terms of seismic and thermal performance.

The choice of seismic input utilized in the evaluation of structural response is determined by the scope of the analysis, namely, the design of new buildings or damage scenarios on existing buildings. Further, a decision has to be made regarding the intensity measure better able to represent the damage potential of the earthquake. This work reports the results of a large set of nonlinear dynamic analyses on structural types representing reinforced concrete buildings widely present in the Italian and European built environments. Seismic input comes from both natural recordings and synthetic data. The maximum interstory drift has been selected as the response parameter better able to represent the structural and nonstructural damage level. The use of a computer code able to generate spectrum-compatible accelerograms showed that synthetic data provide output that is closer to a natural recording when the accelerograms are not forced to converge to a code response spectrum. The Housner intensity proved to be ...

Guaranteeing adequate safety levels in critical infrastructures such as bridges is essential to modern societies and their vital services. Bridges with reinforced concrete structures are subject to deterioration, especially due to corrosion effects. Gerber saddles are among the key components of bridges which are especially exposed to environmental actions due to their position and reduced possibility of inspection. In this paper, a framework for the durability analysis of these components is proposed, considering the simultaneous presence of permanent loads and environmental actions under the form of chloride ions. Nonlinear numerical simulations adopting the finite element code ATENA are performed, accounting for chloride ingress analyses. The presence of cracks (due to applied loads and/or design/construction defects) which may speed-up corrosion propagation, steel reinforcement loss, cracking and spalling, and their effects on the load-bearing capacity is considered. This framework has been applied to the Gerber saddles of a prominent reinforced concrete (RC) bridge, namely the Musmeci bridge in Potenza, Italy. Durability analyses made it possible to evaluate the saddles’ strength capacity (i) at the time of construction, (ii) after forty-five years since the construction, and (iii) at an extended time of fifty years. The results show that corrosion can influence both the ultimate load capacity and the collapse mechanism.