Risk assessment of ANAS bridge stock in the north-east of Italy

Abstract

The safety and functionality of bridges are critical to the road network. In Italy, the latest "Guidelines for risk classification and management, safety assessment and monitoring of existing bridges" requires a "Level 4" assessment (most complete) for bridges that may present critical problems. This paper presents a comprehensive campaign of Level 4 verification and transitability assessment of 53 bridges under the responsibility of ANAS S.p.A. (Italian National Road Authority) - Struttura Territoriale Veneto e Friuli Venezia Giulia. This campaign is one of the most extensive ever carried out in the region. For each bridge, research is carried out to determine the historical background and original design, as well as information on interventions, where available. A pre-survey is performed to frame the structural characteristics of the bridges and the geomorphological features of the areas. A drone survey is then carried out to produce a point cloud of each structure. A series of tests are then conducted on the superstructure and substructure to determine the mechanical characteristics and construction details, and on the geology to provide the relevant seismic and geotechnical parameters. The bridges are then represented graphically using BIM methodology. And FEM modelling is carried out with the traffic loads required by the guidelines and according to the vehicles considered for serviceability. As a result, a classification of all the bridges under consideration is obtained with the identification of possible weaknesses of the road network, which will eventually be followed by repair/improvement/adaptation interventions. This work contributes to the advancement of knowledge and practice in the fields of bridge inspection, assessment and management, with reference to the latest scientific, technical, technological and regulatory developments at national and international levels.