This study presents the results of a refined numerical investigation meant at understanding the time‐dependent cyclic behavior of reinforced concrete (RC) bridge columns under chlorides‐induced corrosion. The chloride ingress in the cross‐section of the bridge column is simulated, taking into account the effects of temperature, humidity, aging, and corrosion‐induced cover cracking. Once the partial differential equations governing such multiphysics problem are solved through the finite‐element method, the loss of reinforcement steel bars cross‐section is calculated based on the estimated corrosion current density. The nonlinear cyclic response of the RC bridge column under corrosion is, thus, determined by discretizing its cross‐sections into several unidirectional fibers. In particular, the nonlinear modeling of the corroded longitudinal rebars exploits a novel proposal for the estimation of the ultimate strain in tension and also accounts for buckling under compression. A parametric numerical study is finally conducted for a real case study to unfold the role of corrosion pattern and buckling mode of the longitudinal rebars on the time variation of capacity and ductility of RC bridge columns.

This paper discusses the seismic behavior of reinforced concrete (RC) bridge structures, focusing on the shear–flexure interaction phenomena. The assessment of reinforced concrete bridges under seismic action needs the ability to model the effective non-linear response in order to identify the relevant failure modes of the structure. Existing RC bridges have been conceived according to old engineering practices and codes, lacking the implementation of capacity design principles, and therefore can exhibit premature shear failures with a reduction of available strength and ductility. In particular, recent studies have shown that the shear strength can decrease with the increase of flexural damage after the development of plastic hinges and, in some cases, this can cause unexpected shear failures in the plastic branch with a consequent reduction of ductility. The aim of the research is to implement those phenomena in a finite-element analysis. The proposed model consists of a flexure fiber element coupled with a shear and a rotational slip spring. The model has been implemented in the OpenSEES framework and calibrated against experimental data, showing a good ability to capture the overall response.

Road network functionality after an earthquake is a crucial aspect for an already struck community. In particular, bridges are susceptible to earthquake-induced damages and to lengthy restoration works. This may lead to severe and unexpected disruption of traffic. In this paper, a model for the assessment of the seismic resilience of a road network is presented. The proposed model permits us to evaluate the earthquake-induced perturbations to the functionality of a network in terms of transportation capacities, traffic congestion, and travel times due to bridge damages and subsequent restoration interventions. The evolution over time of the functionality of the network is studied by means of a multi-stage approach describing the evolution of the situation in terms of reducing the normal pre-earthquakes transportation capacities. The methodology has been illustrated with reference to a hypothetical case study, a road network composed of 14 nodes and 31 links.

Well-known methods for seismic performance assessment, such as incremental dynamic analysis (IDA), multi-stripes analysis (MSA) and the cloud method, involve nonlinear response time-history analyses to characterize the relationship between the chosen damage measure versus intensity measure. Over the past two decades, many authors have proposed simplified procedures or nonlinear static approaches to develop fragility. In these procedures, the capacity of the system is evaluated by nonlinear static procedures (i.e., the capacity spectrum method (CSM), the N2 method, modal pushover analysis (MPA)) and the demand is derived by response spectra. In addition to the familiar ones, incremental modal pushover analysis (IMPA) is a novel nonlinear static procedure proposed in recent years, and it is used in this research to present an IM-based fragility estimation. The accuracy and effectiveness of different methods to assess vulnerability are investigated by comparing fragility curves derived by MPA-based cloud analysis, IMPA and cloud analysis against IDA. The comparison gives valuable insights on the influence of scaling on different sets of records; however, a more extended validation is needed to confirm the obtained results and draw more general conclusions. Results arise from two relatively small bins of record motions differing by ranges of Joyner-Boore distance and scattered in a range of magnitude are presented.

One of the biggest issues in civil engineering is the poor performance of concrete repairs. In fact, in Europe only 50% of concrete structures restorations are estimated to be successful, even though rehabilitation costs account for about half of the yearly construction budgets. This research aims at investigating a potential green approach to the sustainability of rehabilitation solutions for infrastructures. Following a simplified analysis of C02 emissions, intervention costs, social aspects, structural performances and other variables considered relevant to the scope, possible rehabilitation techniques are compared and ranked. The following four different options have therefore been designed to be applied to an actual column of the Brabau Bridge in Sardinia (Italy): i. complete removal and replacement of the column, ii. replacement of the damaged longitudinal rebars by machined bars and ultra-high performance fibre-reinforced concrete (UHPFRC) strengthening, iii. longitudinal and transverse fiber reinforced polymers (FRP) wrapping, iv. concrete jacketing. A methodological and procedural strategy is established through multi-criteria analysis that will allow future developments to assess the whole Life Cycle Assessment of the maintenance work.