Strengthening of steel bridge components with externally bonded ultra-high modulus CFRP

The application of the externally bonded (EB) carbon fiber reinforced polymer (CFRP) technique for retrofitting civil infrastructure has been increasingly gaining acceptance and market share. However, investigations on the performance of steel components strengthened or rehabilitated with EB CFRP are rather limited and most of the studies have been dedicated to concrete structures retrofitted with EB CFRP. In recent years, new research opportunities have opened with the emergence of ultra-high modulus (UHM) CFRP to evaluate the performance of UHM CFRP retrofitting technique in steel structural elements. The performance of the retrofitted steel elements is highly influenced by the bond between CFRP and steel interface. Indeed, debonding failure can lead to premature failure of the CFRP retrofitting technique. In this regard, the study of the bond behavior of the CFRP/steel joints is of paramount importance. This study aims to fully understand the behavior of steel components rehabilitated with CFRP and thereby highlighting the influential parameters. To that end, a comprehensive literature review is initially carried out to identify the key parameters that influence the bond behavior of the CFRP/steel interface, and thereby the flexural behavior of the retrofitted elements. In the second phase, a thorough experimental investigation is conducted to fill the existing gaps in the literature. Firstly, a series of double strap CFRP/steel joints are tested under static loading to evaluate various parameters, including the adhesive type, CFRP length, and surface preparation. Additionally, the effect of CFRP elastic modulus on the rehabilitation technique is examined by comparing Normal Modulus (NM) and Ultra-High Modulus (UHM) CFRP with approximately the same tensile capacity. Secondly, the flexural behavior of the CFRP rehabilitated notched steel beams are examined under static loading. The parameters considered in this phase include CFRP type, CFRP configuration, notch depth, anchorage system, and adhesive type. The results reveal that the effect of adhesive type plays a crucial role on the bond behavior of CFRP/steel joints. However, when it comes to the anchored rehabilitated beams, the adhesive impact is negligible on the flexural performance of the beams due to the anchorage mechanisms. The effect of surface preparation type has also been found trivial on the bond behavior of the CFRP/steel joints. Moreover, it is found that UHM CFRP has a shorter effective bond length compared to its NM CFRP counterpart and it generally outperforms NM CFRP in terms of load-carrying capacity

The impact of occupants’ behaviours on building energy analysis: A research review

Over the past 15 years, the evaluation of energy demand and use in buildings has become increasingly acute due to growing scientific and political pressure around the world in response to climate change. The estimation of the use of energy in buildings is therefore a critical process during the design stage. This paper presents a review of the literature published in leading journals through Science Direct and Scopus databases within this research domain to establish research trends, and importantly, to identify research gaps for future investigation. It has been widely acknowledged in the literature that there is an alarming performance gap between the predicted and actual energy consumption of buildings (sometimes this has been up to 300% difference). Analysis of the impact of occupants’ behaviour has been largely overlooked in building energy performance analysis. In short, energy simulation tools utilise climatic data and physical/ thermal properties of building elements in their calculations, and the impact of occupants is only considered through means of fixed and scheduled patterns of behaviour. This research review identified a number of areas for future research including: larger scale analysis (e.g. urban analysis); interior design, in terms of space layout, and fixtures and fittings on occupants’ behaviour; psychological cognitive behavioural methods; and the integration of quantitative and qualitative research findings in energy simulation tools to name but a few

A Conceptual Model for Assessing Circularity Potential of Building Materials at the Product Manufacturing Stage

The construction industry presently accounts for 30% of natural resource extraction and 25% of solid waste generation. The prevailing economy is “Linear” which is summarised as take-makedispose. On the contrary, the “circular economy” model is a systematic model to restore, regenerate and expand the lifecycle of materials. Most of the existing circularity assessment methods are focused on the end-of-life wastage of building materials while neglecting resource consumption and wastage at the product manufacturing stage. Further, these methods only consider direct material flows for assessing the circularity potential of building materials and overlook the indirect material flows associated with product manufacturing. There is a need to develop metrics to assess the circularity performance of building materials more holistically. Therefore, this study proposes a conceptual model to assess the circularity potential of building materials by analysing both direct and indirect material flow processes of the product manufacturing stage including raw material extraction, transportation, and manufacturing. The method used to design the conceptual model includes a comprehensive literature review in two stages. First, the existing circular assessment methods are reviewed to identify the methods used for assessing the circularity potential of building materials. Secondly, the circularity options are explored to develop the circularity metrics. According to the findings of this study, in the absence of a comprehensive method to assess the circularity potential of building materials, the life cycle assessment and material flow analysis are the most prominent circularity assessment methods used. Furthermore, circularity options such as industrial waste (by-products), biodegradability, biofuels, renewable energy, reusability, recoverability, recyclability and product life span are identified as the circularity metrics for building materials at the product manufacturing stage

A Conceptual Model for Assessing Circularity Potential of Building Materials at the Product Manufacturing Stage

The construction industry presently accounts for 30% of natural resource extraction and 25% of solid waste generation. The prevailing economy is “Linear” which is summarised as take-make dispose. On the contrary, the “circular economy” model is a systematic model to restore, regenerate and expand the lifecycle of materials. Most of the existing circularity assessment methods are focused on the end-of-life wastage of building materials while neglecting resource consumption and wastage at the product manufacturing stage. Further, these methods only consider direct material flows for assessing the circularity potential of building materials and overlook the indirect material flows associated with product manufacturing. There is a need to develop metrics to assess the circularity performance of building materials more holistically. Therefore, this study proposes a conceptual model to assess the circularity potential of building materials by analysing both direct and indirect material flow processes of the product manufacturing stage including raw material extraction, transportation, and manufacturing. The method used to design the conceptual model includes a comprehensive literature review in two stages. First, the existing circular assessment methods are reviewed to identify the methods used for assessing the circularity potential of building materials. Secondly, the circularity options are explored to develop the circularity metrics. According to the findings of this study, in the absence of a comprehensive method to assess the circularity potential of building materials, the life cycle assessment and material flow analysis are the most prominent circularity assessment methods used. Furthermore, circularity options such as industrial waste (by-products), biodegradability, biofuels, renewable energy, reusability, recoverability, recyclability and product life span are identified as the circularity metrics for building materials at the product manufacturing stage

Comparing the effect of lecture method and cooperative teaching method on the learning, communication skills, and attitudes of students: a quasi-experimental study

IntroductionStudents can enhance their understanding of contemporary scientific developments by acquiring proficiency in the English language. Teaching approaches play a crucial role in language acquisition. The objective of this study was to evaluate the effectiveness of the lecture method in comparison to the cooperative learning method, specifically focusing on students’ learning outcomes, communication skills, and attitudes.MethodsThis quasi-experimental interventional study was conducted at Sirjan School of Medical Sciences, Sirjan, Iran in 2023 involving a sample of 30 third-semester students. Participants were randomly assigned to one of two groups, namely the lecture-based teaching group and the cooperative teaching group, with each group consisting of 15 members. Before and after the intervention, questionnaires were completed to assess learning, communication skills, and attitude in both groups. Data were analyzed by independent t-test to compare the two groups. Also, the Levene’s test was used to check the assumption of the equality of variances. Besides, the paired t-test was applied to compare results within each group. The chi-square test was utilized to compare the qualitative variables, while analysis of covariance (ANCOVA) test with adjusting the base value of dependent variables was used to compare the mean differences between the two groups after the intervention.ResultsFindings showed a statistically significant improvement in the mean learning score of the cooperative group after the intervention, compared to the score prior to the intervention (p = 0.007). Moreover, the communication skills and attitude scores of students in both the cooperative and lecture groups showed a statistically significant increase after the intervention, as compared to their pre-intervention scores (p < 0.05). Additionally, following the intervention, the mean scores for communication skills and attitudes were significantly higher in the cooperative group compared to the lecture group, with statistical significance indicated by p < 0.001 and p = 0.03, respectively.ConclusionThis study highlights the effectiveness of cooperative teaching over traditional lecture methods in enhancing students’ learning outcomes, communication skills, and attitudes. The findings indicate that cooperative learning fosters greater engagement, collaboration, and significant interaction among students, ultimately leading to improved academic performance and student satisfaction within the educational framework examined

Background correction by wavelength modulation using a microcomputer in atomic emission spectrometry

Ph.D. - Doctoral Progra