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  • Öğe
    Assessing the impact of peripheral vision on construction site safety
    (Emerald Group Holdings, 2022) Kıral, Işık Ateş; Demirkesen, Sevilay
    Purpose: This study aims to observe the impact of peripheral vision on construction safety. The study further intends to create awareness of eye diseases in construction safety, an important root cause for most construction-related hazards and accidents. Design/methodology/approach: This study focuses on the impact of peripheral vision in terms of construction site safety. Experiments were conducted with construction employees with different qualifications, ages, expertise and previous safety training experience. The experiments were conducted with an experiment set consisting of a tangent screen to measure the peripheral angle of the participants. The study measured peripheral vision, which helped determine the vision field accordingly. In this context, a total of 32 participants were investigated in terms of their peripheral visual angle and the field of vision. The data collected were analyzed in terms of several statistical tests such as One-Sample t-test, multivariate ANOVA and multiple linear regression. Findings: The results of the study indicated that there are significant differences in peripheral vision in terms of age of participants, work qualification, work experience, area of expertise and previous safety training experience. The study further revealed that most of the participants failed to satisfy both OSHA requirements about peripheral vision, and normal limits defined in the previous literature. The study further implies that participants, who reported previous sight problems or eye diseases are more vulnerable to construction site accidents. Originality/value: Construction site safety remains a major concern for most construction companies despite the latest developments in technology. Several companies are struggling with poor safety performance, occupational injuries and illnesses, and work-related accidents resulting in fatalities. However, the root causes behind several construction accidents are still vague due to different dynamics in the construction industry. Among these root causes, poor sight, vision and or eye diseases constitute an important part. Hence, the study provides empirical evidence with the workers checked for eye health to help policymakers and industry practitioners in terms of developing awareness for eye-related injuries and accidents and review their safety programs accordingly. © 2022, Emerald Publishing Limited.
  • Öğe
    Geotechnical and geoenvironmental engineering education during the pandemic
    (ICE Publishing, 2021) Jiang, Ningjun; Hanson, James L.; Vecchia, Gabriele Della; Zhu, Cheng; Yi, Yaolin; Arnepalli, Dalinaidu; Courcelles, Benoît; Dawoud, Osama
    This paper reports the impact of coronavirus disease 2019 on the practice and delivery of geotechnical and geoenvironmental engineering (GGE) education modules, including lectures, lab sessions, student assessments and research activities, based on the feedback from faculty members in 14 countries/regions around the world. Faculty members have since adopted a series of contingent measures to enhance teaching and learning experience during the pandemic, which includes facilitating active learning, exploring new teaching content related to public health, expanding e-learning resources, implementing more engaged and student-centred assessment and delivering high-impact integrated education and research. The key challenges that faculty members are facing appear to be how to maximise the flexibility of learning and meet physical distancing requirements without compromising learning outcomes, education equity and interpersonal interactions in the traditional face-to-face teaching. Despite the challenges imposed by the pandemic, this could also be a good opportunity for faculty members obliged to lecture, to rethink and revise the existing contents and approaches of professing GGE education. Three future opportunities namely, smart learning, flipped learning and interdisciplinary education, are identified. The changes could potentially provide students with a more resilient, engaged, interactive and technology-based learning environment.
  • Öğe
    Critical success factors for safety training in the construction industry
    (MDPI AG, 2021) Tezel, Algan; Dobrucalı, Esra; Demirkesen, Sevilay; Kıral, Işık Ateş
    Abstract: Construction is a hazardous industry. The project-based nature and fragmentation in the industry lead to change and uncertainty requiring special expertise. To handle those, construction firms must develop strategies and action plans along with the experience gained from lessons learned. Among the risks, safety risks are of critical importance leading to accidents. Hence, firms need to strengthen their safety programs, review their strategies for safety management, and develop effective safety training sessions to protect their workers. This study focuses on the success factors promoting safety performance. In this respect, a questionnaire was designed and administered to the Engineering News-Record (ENR) 2020 Top 400 Contractors. The questionnaire data was utilized in conducting a factor analysis to group and name the factors considering the total variance. The analysis of the factors resulted in six-factor groups; namely, project and firm-related factors, demographic factors, practical factors, motivational factors, organizational factors, and humanrelated factors. Project and firm-related factors were found to be the most essential factor group in terms of promoting the effectiveness of safety training. The results of this study are expected to guide industry practitioners in terms of reviewing and revising their safety training programs.
  • Öğe
    A mixed model-based Johnson's relative weights for eco-efficiency assessment: the case for global food consumption
    (Elsevier Inc., 2021) Abdella, Galal M.; Küçükvar, Murat; Ismail, Radwa; Abdelsalam, Abdelsalam G.; Cihat Onat, Nuri; Dawoud, Osama
    Abstract Eco-efficiency composite indicators are widely accepted as the ratio of environmental impact to created economic value. These indicators are realistic measures for assessing sustainability performance considering the economy and environment. The weights reflect the importance of indicators to the aggregated environmental impacts. Estimating the relative weight of indicators is highly subjective, and therefore the search for a single unique weighting method has been going on for years. The regression-based weights are one of the most recent trends in sustainability modeling. Since these methods are designed initially to investigate the impact of multiple variables on a response variable rather than to estimate weights, some drawbacks are associated with their potential to provide proper weights. This paper presents a novel weighting approach integrating linear mixed-effect models with Johnson's relative weights to address these drawbacks and provide meaningful relative weights for eco-efficiency composite indicators. The proposed approach's operational and computational procedures are illustrated using a real example, and the eco-efficiency of food consumption of 38 countries is estimated for the period between 1990 and 2012 using a consumption-based sustainability accounting method. The findings have shown that energy use and GHG indicators are the most critical contributor to global food consumption's environmental impacts. The country-based eco-efficiency performance in this work has shown that China, India, and Russia are located in the low eco-efficiency score class. The Spatio-temporal analysis downgraded the geographical location's significance on the trends of eco-efficiency behavior in time and space. On the other hand, it revealed the different types of emerging hot spots over the world.
  • Öğe
    Experimental behaviour and failure of beam-column joints with plain bars, low-strength concrete and different anchorage details
    (Pergamon-Elsevier Science Ltd, 2020) Coşgun, Cumhur; Türk, Ahmet Murat; Mangır, Atakan; Coşgun, Turgay; Kıymaz, Güven
    In framed structures, both steel and reinforced concrete, beam-column joints play a very crucial role in terms of seismic resistance. Under the effects of high lateral seismic loads, beam-column joints are subjected to high forces and moments and their behaviour have a significant influence on the response of the structure. Poor seismic performance of inadequately detailed joints can lead to the total or partial collapse of reinforced concrete frame structures. The use of low strength concrete, plain reinforcing bars, problematic anchorage details and inadequate transverse reinforcement in beam-column joints are the factors increasing the failure risk of the structures during severe earthquakes. In this paper, an experimental study on the cyclic behaviour of reinforced concrete exterior beam-column joints is presented. The study aims at investigating the effects of the longitudinal beam reinforcement anchorage detail on the joint performance and quantifying the level of contribution of retrofitting the joints by fiber reinforced polymer sheets (FRP). Three different details were considered in the test program including the longitudinal reinforcement of the beam being anchored within the joint with 90-degree hooks, 180-degree hooks and straight bar (no hook). All of the test specimens were produced using low strength concrete and plain bars to represent the conditions of joints of existing deficient reinforced concrete building structures. In the first series of tests, four 2/3 scale reinforced concrete beam-column joint specimens were tested by adopting a displacement controlled and quasi-static load application method to assess the performance of joints with the above-mentioned anchorage details. The load was applied in a reversed cyclic fashion. The second series of tests were carried out on two additional specimens with the same details as described above but strengthened using FRP sheets. The response of the specimens were evaluated and compared in terms of load-drift, displacement hysteretic behaviour. It was found out that the problematic anchorage details have a very significant adverse effect on the seismic performance of the joints. On the other hand, FRP retrofitting has resulted in a significant increase in peak loads and sustained ductility particularly for the specimens for which reinforcement slippage was not a governing mode of failure.
  • Öğe
    Bio-mediated soil improvement: the way forward
    (Wiley, 2020) Jiang, Ning-Jun; Tang, Chao-Sheng; Hata, Toshiro; Courcelles, Benoit; Dawoud, Osama; Singh, Devendra N.
    Bio-mediated soil improvement involves the usage of microbes to improve soil engineering performance through a series of bio-geochemical processes. In particular, Microbially Induced Calcite Precipitation (MICP), a ubiquitous bio-geochemical process that occurs in soil and results in permanent inorganic cementation between soil grains, has received the greatest research focus. While substantial progress has been made to develop MICP as a mainstream soil improvement technique, we still need to: (a) improve our understanding of the fundamental microbial, chemical and flow processes involved; (b) achieve multi-functionality by coupling engineering performance enhancement with ecological, environmental and carbon footprint benefits; and (c) maintain ecological balance and environmental friendliness, avoid long-term deterioration and lower the energy demand.
  • Öğe
    Experimental and numerical investigations of the influence of partial replacement of coarse aggregates by plastic waste on the impact load
    (Taylor & Francis Ltd, 2020) Al-Tayeb, Mustafa M.; Zeyad, Abdullah M.; Dawoud, Osama; Tayeh, B. A.
    The effect of partial replacement of coarse aggregate by plastic waste on the performance of concrete under impact three-point bending loading was investigated experimentally and numerically. Specimens were prepared for 5%, 10% and 20 % replacements by volume of coarse aggregate. For each case, three beams of 100 mm wide, 50 mm deep and 400 mm long were loaded to failure in a drop-weight impact machine by subjecting it to 30 N weight from 400 mm height, while another three beams of the same size were tested under static load. The load-displacement of beams of concrete with plastic waste subjected to static and impact loads were studied. The dynamic beam behaviour was also analysed numerically using the finite-element method (FEM) based LUSAS software. In general, the experimental results reveal that the impact tup, inertial load and bending load increase with the increase in the percentage of coarse aggregate replacement by plastic waste, while the static peak bending load always decreases. The concrete with plastic waste is stronger and more energy-absorbing under impact loading, than under static loading. The predicted load against displacement behaviours of both ordinary concrete and concrete with plastic waste, are well matched with the experimental results.
  • Öğe
    A spatial multi-criteria analysis approach for planning and management of community-scale desalination plants
    (Elsevier, 2020) Dawoud, Osama; Ahmed, Taha; Abdel-Latif, Mahmoud; Abunada, Ziyad
    The rapid deterioration of the groundwater quality in the Gaza Strip-Palestine has increased reliance on community-scale brackish-water desalination plants (CBDPs). However, the escalating numbers of CBDPs is associated with poor operation practices and exhibit various adverse impacts, while the existing regulatory framework of this sector is still lacking the necessary tools for identifying and mitigating these impacts. The current study employed a GIS-based Multi-criteria Analysis (MCA) approach to plan and manage the existing and proposed CBDPs in Gaza Strip, Palestine. The criteria account for the various possible effects including: level of chloride and nitrate in the groundwater, variation in the water-table depth, population density, potential production capacity of CBDPs and operation hours, distance to the pumping wells, sea shoreline, and point-source contamination sites. The results showed that the locations of around 53% of the existing CBDPs are unsuitable; and the CBDPs exhibit potential risks to the environment. The study revealed that 65% of the total area of Gaza Strip would be unsuitable for CBDPs operating in a capacity above the current average. This highlights the significance of regulating the operational conditions of the existing CBDPs according to their geographical location and considering different alternatives of supply-demand schemes.