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In professional practice, the design and verification of Reinforced Concrete (RC) and Prestressed Reinforced Concrete (PRC) structures are performed using a simplified calculation provided by the Eurocodes that limits resistance but that also includes a certain level of structural safety. Some aspects that directly affect the simplified methods involve the use of linear constitutive laws of materials. The use of non-linear laws is evident in the exploitation of reservoirs of strength and deformations of plastic materials in the Ultimate Limit State. The purpose of this research is to evaluate the increase in resistance to bending actions during the plasticization of the beam of existing bridges to support the decision-making process of the engineer in the assessment of existing structures. To achieve this, two codes (MEG Ductility, MEG Fiber Sections) were developed to provide the moment–curvature diagram of RC and PRC sections using non-linear bonds, and in this paper, the study of RC sections is reported. Furthermore, through a push-down analysis, two RC and PRC viaducts have been analyzed using the moment–curvature characteristics obtained from the realized codes and by varying the non-linear constitutive bonds. The results of this study provide valuable insights into the behavior of RC structures under bending actions and demonstrate the importance of considering non-linear material laws for accurate structural assessments. The findings contribute to the enhancement of the decision-making process of engineers when dealing with existing infrastructures.

European countries are characterized by an extensive infrastructural network, mainly built around the 1960s and 1970s. In that period prefabrication processes were starting to gain ground, and one of the most spread and studied typologies of bridges was constituted by reinforced or prestressed concrete decks. Those structures have gone through years of service, which caused the inevitable degradation of the materials and relevant deterioration of structural elements. Moreover, the design and construction processes of that period have soon become obsolete, and the knowledge relative to the influence of detailing increased significantly. One particular element that has been commonly used has been the half-joint, which is easy to prefabricate and has a strategic impact. However, in recent years this solution is showing critical aptitudes in resisting structural degradation and material decay. In addition, structural health monitoring (SHM) strategies are gaining attention since they are a very useful tool for gathering information on the current state of the structure and then for evaluating intervention plans to improve safety. Indeed, existing bridges, despite their working age, are still crucial to the development and sustainability of community life, and their decommissioning would be an act of critical impact on the communities (e.g., economy, logistics, sustainability). This contribution presents the design and the simulation of laboratory tests on half-joints of reinforced concrete beams that will be developed at the Politecnico di Torino in a subsequent step of the present research. They are designed to test and compare different monitoring techniques along with different steel reinforcement configurations. Specifically, the first part of the manuscript focuses on a review of the literature regarding the design, strengthening, and monitoring of half-joints. Subsequently, the laboratory setup to test half-joints is presented along with the numerical simulation to support the experimental design. Laboratory tests will involve the use of monitoring systems to detect the local response of the system and also to propose new solutions specifically for this type of connection using emerging technologies. Numerical collapse simulations show the effect of different reinforcement configurations and the collapse behavior.

Orthotropic steel deck (OSD) bridges are lightweight constructions which are convenient, especially for the achievement of long spans. Conversely, due to the stress concentration in correspondence to the numerous and unavoidable welded construction details, this bridge typology is prone to fatigue cracking under the effect of cyclic loading with high-stress amplitudes. Existing OSD bridges are particularly vulnerable to fatigue damage accumulation because of the dated standards adopted at the time of their design and the fact that heavy lorries have increased in travel frequency and weight. In the present paper, a case study of a northern Italian existing highway viaduct, built in the 1990s, is presented and analyzed. The fatigue damage accumulation was carried out according to the fatigue load models for road bridges reported in Eurocode EN 1991-2 and the assessment criteria indicated in EN 1993-1-9. The stress amplitude, in correspondence to the critical details of the bridge, is assessed by means of detailed finite-element calculations carried out with the software MIDAS GEN®. The amplitude and frequency of the travelling weights are assessed based on real traffic monitoring from the highway. Moreover, an automatic “rain-flow” algorithm is implemented, which is able to detect each nominal stress variation above the fatigue limit. In general, the bridge is not fully compliant with today’s standards when considering the entire duration of the prescribed life of the design. Countermeasures, like lane number reductions and lane reshaping, are critically analyzed since their effectiveness is questionable as far as the reduction in heavy traffic is concerned. Other interventions, like the replacement of the pavement in order to improve the stress redistribution upon the connection details below the wheel footprint, and continuous bridge inspections or monitoring, look more promising.

ABSTRACT Nanomaterials observe specialized properties relative to gross materials. Due to their small size, specialized nanomaterial properties include decreased reactivity, an increased surface area to volume ratio, heightened structural properties, and in some cases, antimicrobial and antibacterial effects. Current researchers are looking to use nanoparticle/nanomaterial properties to solve prevalent dental issues that cannot be addressed with traditionally used materials. This paper will serve as an extensive review of current nanomaterial applications as they pertain to dental fillings and dental filling processes. Comparative assessments of traditional materials used in dental fillings will be made as well as comparative assessments of currently used nanomaterials in dental fillings. Material comparisons are based on criteria pertaining to biocompatibility, toxicity, reactivity, cost, and antimicrobial/antibacterial properties. When comparing the three most currently used dental filling nanomaterials – Carbon-Based Nanotubes, Silica Nanoparticles and Silver-Coated Nanoparticles – it was observed that Silica Nanoparticles demonstrated the greatest material advantage and should be recommended for continued use. Issues regarding future developmental dental filling applications of graphene nanoparticles, organic nanoparticles and gold nanoparticles will also be discussed. Keywords: Nanomaterials, antibacterial, dental fillings, silica resins, biocompatibility.