Durability enhancement of half-joints in RC bridges through external prestressed tendons: The Musmeci Bridge's case study

This paper numerically investigates the effect of post-tension interventions to strengthen the deteriorated half-joints of the Musmeci Bridge in Potenza (Italy), with the primary objective of increasing the ultimate load-bearing capacity and monitoring the secondary effects in terms of preventing or limiting cracking patterns. Bearing this in mind, the study aims to investigate the role of the reinforcement detailing, of the post-tension stress and of the corroding time in the presence of chlorides, outlining the intervention ability to improve the structure's durability. To this end, nonlinear finite element models are provided with chloride ions diffusion analysis to investigate corrosion initiation and progress in reinforced concrete elements and account for deterioration due to two scenarios (45 and 95 years). Results show the significant impact of reinforcement layout as the presence of inclined bars increases the ultimate load by about 86 %. The ultimate load improvement is in the range 50–55 % when the intervention is carried out after 45 years while it is equal to about 30–35 % if a period of 95 years is last since the construction. This latter highlights the significant influence of the intervention timeliness on structural durability

Durability of gerber saddles in RC bridges: Analyses and applications (Musmeci Bridge, Italy)

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

The Italian guidelines on risk classification and management of bridges: Applications and remarks on large scale risk assessments

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

Cancer cell metabolism in hypoxia: Role of HIF-1 as key regulator and therapeutic target

In order to meet the high energy demand, a metabolic reprogramming occurs in cancer cells. Its role is crucial in promoting tumor survival. Among the substrates in demand, oxygen is fundamental for bioenergetics. Nevertheless, tumor microenvironment is frequently characterized by low-oxygen conditions. Hypoxia-inducible factor 1 (HIF-1) is a pivotal modulator of the metabolic reprogramming which takes place in hypoxic cancer cells. In the hub of cellular bioenergetics, mitochondria are key players in regulating cellular energy. Therefore, a close crosstalk between mitochondria and HIF-1 underlies the metabolic and functional changes of cancer cells. Noteworthy, HIF-1 represents a promising target for novel cancer therapeutics. In this review, we summarize the molecular mechanisms underlying the interplay between HIF-1 and energetic metabolism, with a focus on mitochondria, of hypoxic cancer cells

Post-earthquake rehabilitation of healthcare buildings: The case study of the mirandola hospital

Recent earthquakes in Italy and other countries have shown the fragility of hospital complexes which resulted in many cases unusable due to structural and non-structural damage. Depending on the extent of damage, unusable hospitals were reopened after some weeks/months, or affected by long rehabilitation intervention or demolished. In order to allow for a prompt resumption of the social activities of the local communities, the usability evaluation carried out in the immediate aftermath of a seismic event is a crucial step to address the short-term countermeasures and to obtain a gross estimate of the economic losses. After the first weeks, it is often necessary a more detailed assessment which allows for a more accurate evaluation of damage and, more importantly, about the reparability of the structure along with the study of feasible intervention strategies. This latter activity needs detailed analyses based on increased knowledge of the structure. Keeping in mind the objectives of detailed post-earthquake assessment and reparability evaluations, the Santa Maria Bianca hospital of Mirandola, damaged by the Emilia 2012 earthquake, has been analyzed as a case study. Analyses were devoted to defining an upgrading strategy to match the code serviceability limit states (damage limitation and occupancy). The selected strategy included solutions to carry out most of the work from outside, to limit the downtime of the building as well as reconstruction of demolished non-structural elements. Further analyses were made in order to check the effects of the upgrading strategy under the seismic actions recorded during the 2012 Emilia earthquake. These analyses highlighted that even the upgraded hospital building could not be able to remain operational after a new seismic event having the same intensity as the 2012 event, underlining the need of more stringent design criteria for strategic structures like hospitals that are requested to provide healthcare services even more when strong earthquakes occur

Level 3 Assessment of Highway Girder Deck Bridges according to the Italian Guidelines: Influence of Transverse Load Distribution

The Italian Ministry of Infrastructure and Transportation adopted the guidelines on risk classification and management, safety assessment and monitoring of existing bridges through the Decree No. 578 dated 17 December 2020. This document must be used by all managing entities to prevent damage due to a lack of maintenance to these crucial components of the infrastructure system. The approach of the guidelines for existing bridges is developed across six levels, ranging from Level 0 to Level 5. The research work presented in this article is focused on Level 3, which pertains to preliminary assessments conducted on existing bridges. Through an automated procedure, the preliminary verification is performed by comparing bending and shear stress generated by traffic load schemes extracted from previous standards with the ones based on the current code. These loads are applied to a series of girder deck models, selected through a statistical study conducted on a database of bridges. Performance indices are derived from the comparison to evaluate the adequacy of previously designed and constructed structures by applying the load models specified in the current regulations for designing new bridges. The analysis results highlight a performance gap, which varies depending on the standard code at hand

FIRE PLANNING OF URBAN-RURAL INTERFACE IN OPEN SOURCE GIS ENVIRONMENT: CASE STUDY OF THE APULIA REGION (SOUTHERN ITALY)

Abstract. Fires represent one of main challenges of the last decades as global changes are causing an increase in economic and environmental damages. Indeed, just in 2017, more than 10,000 km2 of land were burned in Europe, causing significant damage to both the natural heritage (25% of burned areas were part of Natura 2000 protected areas) and the economy with estimated losses around 10 billion euros. In addition, every year there are losses of human life that make even more necessary new strategies of action and monitoring. Therefore, an efficient management of forecasting, prevention, active fight and post fire phases, is essential to make the territories less vulnerable and reduce the impacts on human lives. But these steps require an integrated approach of different tools in order to make faster and more efficient the different operations. In this context, the study illustrates the expeditious and standardized methodologies in open source GIS environment proposed in a research project with the Civil Protection of Apulia Region in order to implement a vulnerability index to improve operations in forecasting, emergency management in real-near time and post-event analysis in urban-rural interface. All the techniques and methodologies proposed were based on the use of QGIS software as it is a highly user friendly software that can be easily used even by non-specialized technicians. Moreover, the methodologies have been validated through a direct comparison with the tools currently in use in Civil Protection Department of Apulia Region

Experimental and numerical evaluation of coring effects in reinforced concrete columns

The knowledge of in-situ material properties is the first step in the assessment process of existing structures and, where needed, in the design of the consequent strengthening interventions. In order to achieve this goal, destructive (DT; e.g., cores) and non-destructive (NDT; e.g., ultrasonic, rebound) test methods are generally adopted, either alone or combined. Although many literature papers and guidelines propose to minimize the number of cores in the estimation of the concrete strength in reinforced concrete structures, the European and Italian codes prescribe that the estimation of in-situ strength has to be mainly based on cores drilled from the structure (DT). In this framework, the paper reports results of an experimental program aimed at evaluating the effects of core tests on RC columns, as well as the effectiveness of the structural restoration of drilling holes. Specifically, three sets of column specimens have been considered: (i) drilled columns, (ii) drilled and subsequently restored columns, and (iii) reference not drilled (as-built) columns. Compression tests have been carried out on each column and the results have been compared with the prediction based on codes or other literature approaches. This helped to recognize the main phenomena affecting the column members behavior under axial loads. At the same time, the authors calibrated detailed finite element models based on the experimental results of the tests carried out on column specimens. An advanced Fem tool was used to set-up 3D models. Numerical simulations aimed at better understanding the failure mechanism, especially in the presence of the hole related to the core extraction. The role of longitudinal and transverse reinforcement has been evaluated, highlighting that concrete crushing in the areas around the hole causes the early buckling of rebars, leading to premature failure of drilled column specimens

Liposome-mediated inhibition of inflammation by hydroxycitrate

Hydroxycitrate (HCA), a main organic acid component of the fruit rind of Garcinia cambogia, is a natural citrate analog that can inhibit the ATP citrate lyase (ACLY) enzyme with a consequent reduction of inflammatory mediators (i.e., nitric oxide (NO), reactive oxygen species (ROS), and prostaglandin E2 (PGE2)) levels. Therefore, HCA has been proposed as a novel means to prevent, treat, and ameliorate conditions involving inflammation. However, HCA presents a low membrane permeability, and a large quantity is required to have a biological effect. To overcome this problem, HCA was formulated in liposomes in this work, and the enhancement of HCA cell availability along with the reduction in the amount required to downregulate NO, ROS, and PGE2 in macrophages were assessed. The liposomes were small in size (~60 nm), monodispersed, negatively charged (−50 mV), and stable on storage. The in vitro results showed that the liposomal encapsulation increased by approximately 4 times the intracellular accumulation of HCA in macrophages, and reduced by 10 times the amount of HCA required to abolish LPS-induced NO, ROS, and PGE2 increase. This suggests that liposomal HCA can be exploited to target the citrate pathway involved in inflammatory processes