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2007 research outputs found
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Integrating Technology and Heritage Design for Climate Resilient Courtyard House in Arid Region
No full textThis research has investigated the sustainability and climate resilience of courtyard houses of adobe architecture in the UAE. It analyzed design effectiveness in terms of power consumption, CO2 emissions, thermal comfort, and daylight use, employing simulations to assess building structures and construction systems. Adopting a three-phase mixed-methods approach, the study began with a literature review on courtyard house design, construction, and environmental performance, emphasizing sustainable design and passive ventilation. The second phase involved a case study of a UAE courtyard house (Al Midfa), including site visits, interviews, and energy consumption and CO2 emission data collection. The final phase used building energy simulation software to model energy performance and evaluate passive ventilation's role in reducing energy consumption and CO2 emissions, with simulation results validated against real-world data. Advanced Sefaira simulations with the Energy Plus Engine identified one out of seven modified models (M5) as exceptionally thermally efficient, influencing the architectural design of the Al Midfa house. To transform the Al Midfa house into a sustainable climate-resistant structure, the research suggested retrofitting with new glazing and insulation on the inside of external walls and on the roof surface at a combined U-value of 0.4 W/m2to enhance energy efficiency without altering the exterior. A notable innovation was the use of injected cellulose insulation in wall systems, combining efficient insulation with architectural aesthetics, signifying a shift towards energy-efficient interior modifications. The study's findings contribute to the evolution of traditional house designs toward climate change resilience and a sustainable future. Doi: 10.28991/CEJ-2024-010-03-018 Full Text: PD
Multi-Objective Optimization of Stress Concentration Factors for Fatigue Design of Internal Ring-Reinforced KT-Joints Undergoing Brace Axial Compression
No full textStress concentration factors are important to determine fatigue life based on the S-N curve methodology, where the lower the stress concentration factor, the higher the fatigue life. In this work, we developed internal ring-reinforced KT-joints, one of the most commonly used joints in the offshore industry, for the most practical ranges with the least stress concentration factors, followed by the formulation of a novel set of parametric equations for determining the stress concentration factors of internal ring-reinforced KT-joints. Using numerical investigation based on a finite element model and a response surface approach with 8 parameters (λ, δ, ψ, ζ, θ, Ï„, γ, and β) as input and eleven outputs (SCF 0° to SCF 90° and peak SCF), the stress at ten locations around the brace was evaluated, since efficient response surface methodology has been proven to give comprehensive and accurate predictions. The KT-joint with the following parameters: λ=0.951515, δ=0.2, ψ=0.8, ζ=0.31, θ=45.15°, Ï„=0.60, γ=16.25, and β=0.40 had the least stress concentration factor. The KT-joint with the optimized parameters was validated through finite element analysis. The resulting percentage difference was less than 6%, indicating the applicability of the response surface methodology with high accuracy. Doi: 10.28991/CEJ-2024-010-06-03 Full Text: PD
Quantitative Monitoring of Coastal Erosion and Changes Using Remote Sensing in a Mediterranean Delta
No full textThe morphology of coastal regions is continually changing because of both natural and human factors. Monitoring and understanding these changes are essential for efficient coastal management and sustainable development. To protect and develop beaches, quantitative monitoring of coastal changes is crucial. According to this study, there is a persistent erosion issue with the shoreline of the Rosetta region in Egypt. Over the previous century, there has been noticeable erosion. This is mostly because of the Aswan High Dam, which was built in 1964 and decreased runoff and sediment flow. Five Landsat images spanning the years 1980–2023 were utilized in this study. The Nile Delta would be eroding at an alarming rate if action were not taken due to coastal erosion, which is made worse by sea level rise. Our study's primary goal is to evaluate the shoreline of the Rosetta region and identify rates of erosion and accretion as well as patterns of accumulation and erosion using a combination of statistical analysis of the coastline using DSAS software and remote sensing techniques. It also seeks to pinpoint hotspots that require security. In this study, the Shoreline Linear Regression Rate (LRR), End Point Rate (EPR), Shoreline Change Envelope (SCE), and Net Shoreline Movement (NSM) were determined by creating cross-sections perpendicular to the baseline using the Digital Shoreline Analysis System (DSAS). According to the analysis of coastal change, the periods with the highest levels of erosion were between 1980 and 1990, before the protection of the promontory took place. In addition, the results extracted from this study showed a stabilized shoreline between 2000 and 2023 at the Rosetta Promontory and noticeable erosion in the east and west of the promontory. Doi: 10.28991/CEJ-2024-010-06-08 Full Text: PD
Assessing Liquefaction Potential in Alluvial Plains Through Spatiotemporal Analysis Using Liquefaction Probability Index
No full textLiquefaction is one of the most important processes in soil dynamics. It is a loss of strength coupled with a rapid increase in pore pressure, causing soil particles to burst for a short period. Several approaches have been developed to calculate the residual or liquefied shear strength of cohesionless soils. Using the liquefaction probability index (LPI) created by Juang et al. (2003), the primary goal of this publication is to map spatiotemporal variations in the liquefaction potential of deposits in the Oued Drader and Marja Zerga alluvial plains of the mio-plio-quaternary Gharb basin. The cone penetration test (CPT) and semi-empirical techniques developed to measure the risk of liquefaction and create a mapping of liquefiable zones on a national scale for the first time are the primary sources of information used in the computation of the liquefaction potential index (LPI), which will be highly applicable and relevant for upcoming research projects. According to the IPL calculation, liquefaction is expected to be confirmed for the sandy and silty-sandy formations in Oued Drader and Marja Zerga. The spatial-temporal variations will depend on the formation's granulometry, saturation level, and liquidity limit. The lateral and spatial variety of the Marja Zerga and Oued Drader plain deposits is reflected in this architecture of liquefaction variation. Doi: 10.28991/CEJ-2024-010-06-018 Full Text: PD
Performance of Asphalt Mixtures Modified with Nano-Eggshell Powder
No full textPrimary issues in pavement engineering, such as rutting, moisture damage, and fatigue cracking, have prompted numerous studies aimed at improving pavement performance. Utilizing biomaterial waste to modify bitumen through nanotechnology is a promising approach to improve asphalt-mixture properties and aligns with goals of sustainability and reducing the dependence on non-renewable resources. Therefore, the primary objective of this study was to investigate the effect of nano-eggshell powder (NESP) as a sustainable bio-modifier for bitumen on the mechanical properties of asphalt mixtures. To achieve this, asphalt mixtures containing 0% (control), 5%, and 9% NESP were developed, and their mechanical properties were investigated through various tests such as moisture damage, Marshall immersion stability, resilient modulus, dynamic creep, double-punch shear, water immersion, and wheel tracking. The results showed that NESP reduced the moisture susceptibility of the mixtures by increasing their tensile strength ratio. Additionally, the durability of the asphalt mixtures improved as the NESP content was increased. Moreover, the addition of NESP significantly enhanced the resilient modulus and dynamic creep of the asphalt mixtures. The double-punch test revealed that the NESP improved the rutting and fatigue resistance of the asphalt mixtures. Furthermore, the water-immersion test indicated that NESP enhanced the adhesion properties between the bitumen and the aggregate. Finally, the wheel-track test results suggested that the mixtures modified with NESP exhibited a lower rut depth than the control mixtures. Notably, 9% NESP was optimal for enhancing the mechanical properties of the asphalt mixture. The study demonstrated that using NESP as a bio-modifier for bitumen is feasible and offers a more sustainable alternative to traditional bitumen additives. Doi: 10.28991/CEJ-2024-010-11-016 Full Text: PD
Natural Rubber Latex-Modified Concrete with Bottom Ash for Sustainable Rigid Pavements
No full textThis article investigates the viability of using natural rubber latex (NRL)-modified concrete with bottom ash (BA) as a partial replacement for river sand in sustainable rigid pavements. Concrete mixes with 10% and 20% BA replacement ratios and varying NRL dosages (0%, 1.0%, 1.5%, and 2.0% by weight of cement) were prepared and evaluated for their mechanical and microstructural characteristics. Results showed that BA substitution decreased the compressive strength of concrete. However, the addition of NRL at an optimal dosage of 1.0% significantly improved both the compressive and flexural strengths. The 10%BA+1.0%NRL and 20%BA+1.0%NRL mixes exhibited mechanical properties surpassing the control mix and meeting the minimum requirements for rigid pavement materials. However, excessive NRL content (1.5% and 2.0%) led to a reduction in mechanical strength. Scanning electron microscopy analysis exhibited a denser and more compact matrix in NRL-modified BA concrete, with NRL films enhancing the interfacial bonding and crack-bridging mechanism. Nonetheless, excessive NRL content resulted in the formation of abundant and thicker NRL films, which disrupted the continuity of the cement matrix and created weak zones. X-ray diffraction analysis confirmed the existence of crucial crystalline phases and their optimal balance in the 20%BA+1.0%NRL mix, contributing to its superior performance. Mixes with excessive NRL contents exhibited lower intensities of quartz, calcite, and portlandite peaks, indicating a disturbance in the proper formation and growth of essential crystalline phases. The findings demonstrated the potential of NRL-modified BA concrete as an eco-friendly and high-performance alternative for sustainable rigid pavements when using an optimal NRL dosage, promoting the employment of waste resources and reducing the environmental impact of the construction industry. Doi: 10.28991/CEJ-2024-010-08-05 Full Text: PD
Investigation of an Innovative Technique for R.C. Piles Reinforced by Geo-Synthetics Under Axial Load
No full textThe use of alternative reinforcement material to enhance the performance of the pile capacity has gained increasing interest in recent years. This study seeks to probe the improvement of the ultimate pile capacity, reduction the deformation, and the financial results of using alternative reinforcement material such as glass fiber-reinforced polymers (GFRP), geosynthetics geogrids, as well as a combination of geosynthetics geogrids and a central steel bar. Axial load investigations were conducted on circular piles with 150 mm diameter and 1050 mm height. The experimental results revealed an improvement in the axial capacity of up to 25.4% and an enhancement in performance represented in ductility. Furthermore, financial and weight comparisons showed a decrease in the cost by up to 15%. Moreover, a nonlinear finite element (FE) study with Abaqus software was employed to standardize the numerical outcomes with the laboratory findings. The FE analysis was also verified with the previous studies. The 3D nonlinear finite element numerical model performed showed convergence with and without representing the surrounding soil of the pile; thus, confirming the adequacy of the experimental setup adopted. Finally, a suggested theoretical equation is developed to evaluate the change in pile axial load capacity based on the use of different reinforcement materials. The application of the proposed theoretical equation provides further insight into the governing equation involving different reinforcing materials. Doi: 10.28991/CEJ-2024-010-10-011 Full Text: PD
Effectiveness of Different Configurations of Ferrocement Retrofitting for Seismic Protection of Confined Masonry: A Numerical Study
No full textA ferrocement layer, which consists of a wire mesh and cement mortar, is a popular retrofitting method for existing structural elements, particularly wall or slab panels. This paper presents a study on the effectiveness of different configurations of ferrocement for seismic retrofitting of confined masonry through finite element analysis. The masonry panel was modeled using expanded brick-unit elements, where the element was expanded in size by as much as half of the mortar thickness, and an interacting zero-thickness interface was applied to mimic the elastic-plastic and damage behavior during tension, shear, and compression. The concrete damage plasticity (CDP) model was used to model the confining reinforced concrete frame and overlay mortar in the ferrocement layer, and the reinforcing bars and wire mesh were modeled using elastic-plastic behavior. In the present numerical study, nine models were subjected to cyclic and pushover shear test simulations, considering the effects of the number of ferrocement layers and the wire mesh orientation. The volumetric ratio of the wire mesh to the masonry (Ïwm) ranged from 0.48% to 1.92%, whereas the ratio of the mortar overlay to the masonry (Ïmo) varies from 10.42% to 41.66%. Based on the increase in the lateral strength, the model with the largest volume of the ferrocement layer exhibited the largest increase in strength. However, the most cost-effective retrofitting configuration was presented by model DS-1-45, in which a single layer of ferrocement was applied on both sides of the wall using 45° of wire mesh orientation. The DS-1-45 model provided a lateral strength increase of more than 6 times compared to the original unreinforced model. Doi: 10.28991/CEJ-2024-010-09-02 Full Text: PD
Effect of Porous Rectangular Type Baffle Block Angle on Hydraulic Jump Downstream of Spillway
No full textThe elevation of the water surface upstream of the spillway structure increases significantly due to damming, leading to a rapid, supercritical flow downstream. This flow transitions from supercritical to subcritical, resulting in hydraulic jumps (Lj). The placement of a porous rectangular baffle block in the chute acts as an energy dissipator within the channel. This study aimed to investigate the effect of the angle of the porous rectangular baffle block on energy dissipation and hydraulic jumps downstream of the spillway structure. The experiment utilized a two-dimensional (2D) approach to evaluate energy dissipation and hydraulic jumps under various placements of the porous rectangular baffle block in the chute. The results indicated that the water level above the weir (hd) increased, along with turbulence downstream, while energy loss decreased. However, the efficiency of energy dissipation improved as variations in the water level above the weir decreased. A baffle block with an angle (α) of 60° was found to be the most effective in dissipating flow energy and shortening hydraulic jumps. Additionally, an empirical equation was developed for the hydraulic jump length as a function of the downstream Froude number (Fr): Lj=yt (k α hd(Fr-1)^4). The porous rectangular baffle block proved advantageous as it gradually dissipates flow velocity through its pore openings, preventing flow momentum reversal. Doi: 10.28991/CEJ-2024-010-10-04 Full Text: PD
The Performance of Geosynthetic Reinforcement Road Pavement Over Expansive Soil Subgrade
No full textOne of the problems faced in infrastructure development, especially roads, is problematic soils, including expansive soils, which are distributed around 20% of national road construction in Indonesia. Geosynthetics are reinforcement materials that can be used to overcome problematic soils. The study aimed to determine the behavior of expansive soil with geosynthetic reinforcement against swelling potential and swelling pressure in the wetting cycle. The research utilized an experimental approach involving three test concepts. The first was a control test without reinforcement. The second included a combination of geogrid, geotextile, and geomembrane layers, while the third utilized an H2Rx reinforcement layer. Analysis was carried out on the development potential and pressure; the test was carried out for 57 days using displacement sensors and pressure sensors, and data recording was carried out every 5 seconds using a computer. The findings from the results of this study indicated that the presence of reinforcement using a geosynthetic reinforcement layer can overcome the behavior that occurs in expansive soils with swelling potential and swelling pressure. The novelty of this research is the inclusion of a geosynthetic reinforcement layer on expansive soil combined with a drainage layer in the pavement subgrade. Doi: 10.28991/CEJ-2024-010-12-020 Full Text: PD