One of the main limitations to the use of fabric-reinforced cementitious matrix (FRCM) composites for the external confinement of masonry is the lack of accurate formulas for estimating the ...compressive strength and ultimate strain of confined members. With the aim of providing a contribution on the topic, the authors have been carrying out studies on the FRCM-confined masonry for some time and, in a recent study, they proposed some formulations for the prediction of compressive strength. In continuity to that work, an analytical study on the ultimate strain of FRCM-confined masonry is presented in this paper, and preliminary models were derived by considering a wide experimental database compiled from the technical literature. The accuracy of the found relationships was examined based on a comparison with the few formulas published in the literature or reported in international guidelines. To this purpose, it is worth highlighting that the current Italian Guidelines CNR-DT 215/2018 do not provide indications about the estimation of the ultimate strain of FRCM-confined masonry, and the study proposed here attempts to provide a contribution to the mentioned document.
•An analytical study on the behavior of FRCM confined concrete is presented.•A database of compressive tests on FRCM confined concrete cylinders was assembled.•The confinement efficiency by varying ...the type of FRCM system was investigated.•Strength models for FRCM confined concrete were developed through best-fit analyses.•Comparisons with some literature formulations were performed.
Composite materials employing cement-based mortars, usually known as fabric-reinforced cementitious matrix (FRCM) composites, have recently emerged as an attractive solution for the repairing and strengthening of reinforced concrete or masonry members. They represent a promising alternative to the use of Fiber Reinforced Polymer (FRP) composites when there is a need to overcome some of the drawbacks related to the epoxy resin, such as moderate matrix heat and fire resistance, difficulty of application at low temperatures, impossibility of application on wet surfaces, and lack of vapor permeability. This paper presents an analytical study on the confinement of concrete columns with FRCM composites with the twofold objective to: (a) propose new models for the estimate of the compressive strength, and (b) assess existing models available in the literature and in some international guidelines.
To this purpose, a wide database including results of compression tests performed on over 290 concrete cylinders externally wrapped with FRCM was assembled from the literature. The collected results were employed to perform an overall analysis of the efficiency of the FRCM confinement by varying some of the relevant parameters, such as: type of fiber (glass, carbon, steel, PBO or basalt) and geometry of the mesh, number of employed layers, mechanical properties of the inorganic matrix and compressive strength of the unconfined concrete. Relationships for estimating the compression strength of the FRCM confined concrete were then developed through best-fit analyses, and comparisons with some formulations available in the literature and in some international guidelines were performed.
The bonding of steel/fiber-reinforced polymer (SRP/FRP) laminate strips to concrete/masonry elements has been found to be an effective and efficient technology for improving the elements' strength ...and stiffness. However, premature laminate-substrate debonding is commonly observed in laboratory tests, which prevents the laminate from reaching its ultimate strength, and this creates uncertainty with respect to the level of strengthening that can be achieved. Therefore, for the safe and effective application of this technology, a close estimate of the debonding load is necessary. Towards this end, in this paper, a new, relatively simple, semi-analytic model is presented to determine the debonding load and the laminate stress and deformation, as well as the interfacial slip, for concrete substrates bonded to SRP/FRP and subjected to monotonic or cyclic loading. In the model, a bond-slip law with a linearly softening branch is combined with an elasto-plastic stress-strain relationship for SRP. The model results are compared with available experimental data from single-lap shear tests, with good agreement between them.
COVID-19 vaccination has been extended to include children aged 5-11 years. This cross-sectional survey evaluated parental COVID-19 vaccine willingness and hesitancy, and associated factors, for ...their children aged 5-11 years with chronic conditions. A telephone survey was conducted from 14 December 2021 to 4 January 2022. The questionnaire assessed participants' socio-demographic and health-related information, attitudes towards COVID-19 infection, hesitancy, by using the PACV-5 (Parent Attitudes About Childhood Vaccines Survey Tool), and sources of information. A total of 430 answers were collected anonymously. Respondents with no cohabitant who had been infected by SARS-CoV-2 and having been vaccinated against COVID-19 had a higher concern about the severity of COVID-19. The parents' perceived risk that the child could be infected by SARS-CoV-2 was higher in those more concerned about the severity of COVID-19, with an older child, and who had at least one cohabitant positive for COVID-19. Only 38.8% parents were willing to vaccinate their children against COVID-19. Parents who did not need additional information, those with higher education, those who have been vaccinated against COVID-19, those whose child was older, who had received information on this vaccination from physicians, with higher self-reported concern about the severity of COVID-19, and who had a higher perceived risk that their child could be infected by SARS-CoV-2, expressed a greater willingness to vaccinate their child. Overall, 26.3% were high-hesitant, with a PACV-5 score ≥ 7. Respondents who did not get the COVID-19 vaccine, were less educated, with a lower concern about severity of COVID-19, and with a lower perceived risk that their child could be infected by SARS-CoV-2, were more likely to be high-hesitant. New policies and educational programs regarding COVID-19 vaccination for children with chronic conditions are needed to reduce hesitancy and increase vaccination uptake.
This cross-sectional survey explored the attitudes and the reasons, as well their associated factors, for receiving the second booster dose of the COVID-19 vaccine among a sample of all old adults ...and of people with chronic medical conditions attending two randomly selected immunization centers in Naples (Italy). A total of 438 questionnaires were collected. The majority were male (55.1%) and the median age was 71 years. A higher perception of the vaccine's utility, measured with a 10-point Likert type scale, has been observed among males, individuals with a higher perception that COVID-19 is a severe illness, with a higher self-awareness of being at risk of infection, and with a higher trust in the information received. The most reported reasons for receiving the second booster dose included protection of themselves and of their family members from getting COVID-19, fear of acquiring the disease, and having a physician's recommendation. Younger participants, married/cohabitant, and with a higher perception that COVID-19 is a severe illness were more likely to have indicated protecting themselves and their family members as reason for receiving the booster dose. Respondents with a chronic medical condition, with a higher perception that COVID-19 is a severe illness, with a lower trust in the information received, and informed by physicians were more likely to have received the vaccine because they perceived of being at risk of getting a severe form of the SARS-CoV-2 infection. Physicians should play a pivotal role in stressing the importance of the second booster dose and in helping individuals to make decisions.
The objectives of the survey were to explore any changes in the adherence to the three main COVID-19 preventive measures (social distancing, washing hands, wearing face-masks) among 795 individuals ...who received the COVID-19 vaccine booster dose in Italy and to identify the predictors associated. The concern of contracting COVID-19 before the vaccination, after the primary COVID-19 vaccine series, and after the booster dose resulted with a mean value of 7.7, 4.6, and 4.2, respectively. Females, those who had a lower mean self-perceived health status, who perceived COVID-19 as a very serious health problem, who decided to receive the booster dose because they perceived to be at risk of getting COVID-19, and who expressed interest in acquiring more information regarding the COVID-19 vaccine booster dose were more likely to report a higher concern of contracting COVID-19 after the booster dose. Over two-thirds were willing to respect the three main COVID-19 preventive measures following the booster dose. The multinomial logistic regression analysis showed that those who had used all three main preventive measures before and after the second or single dose were less likely to perceive COVID-19 as a serious illness. Those who had used them irregularly were less likely to have used official government organizations and scientific journals as sources of information. This survey provided an understanding regarding the adherence to COVID-19 preventive measures that may help to target policy interventions needed to reduce the spread of SARS-CoV-2.
This paper presents an experimental study undertaken to investigate the seismic behavior of full scale square (300 mm × 300 mm) reinforced concrete (RC) columns strengthened with novel systems ...employing carbon fiber-reinforced polymers (CFRP) wraps. Experimental tests were carried out by subjecting specimens to a constant axial load and a cyclically reversed horizontal force applied in displacement control. Results have allowed for investigating the influence of the used strengthening systems on the specimens’ performance in terms of flexural strength and ductility as well as on the exhibited failure modes. The effectiveness of the studied techniques is also evaluated by comparing the performance of tested specimens with that of companion columns strengthened with alternative CFRP systems investigated in a previous experimental campaign.
Pregnant women, especially those with comorbidities, compared to those non-pregnant, have higher risk of developing a severe form of COVID-19. However, COVID-19 vaccine uptake is very low among them.
...An anonymous questionnaire was administered to randomly selected women 18 years of age that were currently pregnant or had just given birth between September 2021 and May 2022 in the geographic area of Naples. Vaccine hesitancy was assessed using the vaccine hesitancy scale (VHS).
A total of 385 women participated. Women who had not been infected by SARS-CoV-2 and who needed information about vaccination against COVID-19 had a higher perceived risk of being infected with SARS-CoV-2. More than half (54.3%) of the women were very afraid of the potential side effects of the COVID-19 vaccination on the fetus. There was higher concern of the side effects of the vaccine on the fetus among those who did not have a graduate degree, those with high-risk pregnancy, those who had not been infected by SARS-CoV-2, those who were more concerned that they could be infected by SARS-CoV-2, those who did not know that this vaccination was recommended for them, and those trusting mass media/internet/social networks for information. Only 21.3% were vaccinated when pregnant, mostly women with a university degree, those who had been infected by SARS-CoV-2 before pregnancy, those who did not need information, and those who acquired information about the vaccination from gynecologists. Almost three-quarters (71.9%) were willing to receive the vaccination and those more likely were those with a university degree, those who have had at least one relative/cohabitant partner/friend who had been infected by SARS-CoV-2, those who were more concerned that they could be infected by SARS-CoV-2, and those who were not extremely concerned of the side effects of the vaccine on the fetus. A total of 86.4% were highly hesitant. Highly hesitant were respondents who did not get a graduate degree, those less concerned that they could be infected by SARS-CoV-2, and those trusting mass media/internet/social networks for information.
Public health efforts and education campaigns for pregnant women are needed for changing their perception patterns and for supporting gynecologists in promoting the uptake of this vaccination.
Objectives
The aims of this cross-sectional study were to investigate why parents decide to vaccinate, as well as the determinants, their children aged 5–11 years against COVID-19 in Italy.
Methods
...The survey was conducted from January through May 2022. All parents/guardians who came in randomly selected days to immunization centers for the administration of the first dose of the COVID-19 vaccine to their child were asked to complete a questionnaire about socio-demographic characteristics, attitudes toward COVID-19 infection and vaccination, reason(s) regarding their decision to vaccinate their child, and source(s) of information.
Results
A total of 358 questionnaires were collected. Parent's perception that COVID-19 is a severe illness for the child, assessed using a 10-point Likert scale, was 7.5. The overall mean scores of the risk perception for their child of having the COVID-19 before and after the vaccination were 8.1 and 6.3. A significantly higher parents' level of risk perception for their child of having the COVID-19 after the vaccination has been observed among those not having a university degree, those with the child having at least one chronic medical condition, and those who perceived that COVID-19 is a severe illness for the child. The mean value of respondent trust in the information provided by the pediatricians on a 10-point scale Likert type was 7.6. Female, not having a university degree, higher perception that COVID-19 is a severe disease, not having received information about the vaccination from pediatricians, and needing information had a significantly higher concern of side effects after the vaccination. The most common reasons for vaccinating their children included wanting to protect the child against COVID-19, to attend the school with less risk, to prevent the transmission to family members, and to practice sport and other activities with less risks. Participants with a university degree were more likely to have vaccinated their child for attending the school and practicing sport and other activities with less risks.
Conclusions
More publicity should be promoted among parents of children aged 5–11 years which would increase the coverage rates and thus lower the transmission of SARS-CoV-2 and reduce the occurrence of COVID-19.
PDF
