ABSTRACT
The most significant investments in economic and technological terms on infrastructural networks are often focused on major structures, such as bridges and viaducts. These structures are indeed the most exposed to deterioration phenomena induced by harsh climatic conditions, ageing, increased volumes and weights of traffic axle loads. Generally, an increasing demand to improve the management methods of bridges is becoming evident. Many road and rail managing authorities have made a significant effort to develop bridge management systems (BMSs) (Zonta et al. 2007, Pellegrino et al. 2011), in order to obtain useful information when allocating resources and establishing management policies in a bridge network (Carturan et al. 2014).
Past experiences have shown how bridges in their life can experience structural problems due to environmental conditions and natural disasters: concrete cover damage that exposes bars to atmosphere, steel corrosion, concrete damage by icing cycles, ageing of structural materials are some causes leading to the degradation of reinforced concrete bridges’ mechanical properties (Zanini et al. 2013; Biondini et al. 2014), thus amplifying the effects of a quake occurrence
The optimal distribution of a limited budget is therefore a challenge connected to prioritization issues in order to maximize the service level of an infrastructural system: in this way, maintenance interventions against natural ageing and seismic retrofit interventions aimed to reduce local/global structural vulnerabilities are interacting issues, important for a proper bridge management process for a public authority or a private company.
Although these topics have been widely studied by several authors considering them as separate issues, in this work, ordinary maintenance and seismic retrofit – and related costs – of existing bridges are treated as complementary and interacting problems: the novel contribution is therefore represented by the calibration of cost models taking into account synergy effects in restoration of bridges deteriorated and needing seismic retrofit.
Cost models were calibrated on the basis of a population of bridges in the Vicenza province, North Eastern Italy and could allow either public authorities or private managing companies to estimate economic indicators for the estimation of the amount of resources needed for bridge maintenance and retrofit in areas subject to seismic events.
