2031 research outputs found
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Investigation of an Innovative Technique for R.C. Piles Reinforced by Geo-Synthetics Under Axial Load
Get PDFThe 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
Comparative Evaluation of Compressive Strength in Earth Blocks Enhanced with Natural Fibers
Get PDFPortland cement is a key component in the production of concrete blocks; however, its production has an extensive carbon footprint that contributes towards climate change. In addition, the availability of aggregates is also often challenging and, as such, leads to production delays of concrete blocks, which ultimately causes delays in the completion of construction projects and constant price increases. The price increase of construction materials such as concrete blocks tends to affect the quality of houses being constructed in rural communities of the Pacific Island Countries (PICs), and this calls for the development of a low-cost alternative to ensure housing quality is not compromised. This project is being carried out to develop earth blocks as an environmentally friendly and sustainable substitute for concrete blocks that are widely used in the construction industry. Coir (derived from coconut fibers) and bamboo fibers were incorporated into these blocks as reinforcement materials, aiming to achieve the same level of strength required for use in construction. Additional adhesion of the earth block was provided by the usage of cement. The earth blocks were cured for 7, 14, and 28 days, after which they were subjected to various tests, including a compressive strength test, water absorption test followed by wet compressive strength test to compare its performance to ensure it has sufficient strength for it to be introduced into the market as a more eco-friendly, low-carbon-emission, and cost-effective construction material. The maximum compressive strength obtained during the test was 3.24 MPa. Following a comprehensive analysis of the data attained, the composition of 15% cement and 0.75% bamboo fiber emerges as the most ideal choice for creating marketable earth blocks. This composition strikes a balance between providing adequate strength and ensuring minimal reduction in overall strength when the blocks are exposed to wet conditions. Doi: 10.28991/CEJ-2024-010-10-013 Full Text: PD
Green Construction and Local Wisdom Integration for Sustainability: A Systematic Literature Review
Get PDFThe construction industry's environmental impact necessitates a sustainable shift to mitigate resource depletion, emissions, and biodiversity loss. Integrating local wisdom offers innovative, adaptive solutions grounded in deep environmental understanding, potentially transforming construction practices toward sustainability. This study aims to identify aspects, challenges, impacts, and strategies in green construction practices integrated with local wisdom. The PRISMA framework methodology was used to conduct a comprehensive systematic review with qualitative analysis using NVivo software. Nine aspects of green construction integrated with local wisdom were identified, with cultural heritage preservation the dominant aspect. Eleven challenges were uncovered, with balancing tradition and innovation as the main challenges. Seven impacts on the economy, society, and environment were identified, with construction cost efficiency, improvement of community quality of life, and promotion of a circular economy and sustainable waste management as the dominant impacts. Thirteen strategies were identified, with active engagement of local communities in the construction process as the main strategy. The novelty of this research is a comprehensive review of the integration of green construction with local wisdom, which can be used as a guide in sustainable construction practices responsive to local environmental and social conditions and promote economically, socially, and environmentally sustainable development. Doi: 10.28991/CEJ-2024-010-11-020 Full Text: PD
An Advanced Adaptive Mesh for Beam-Column Finite Elements on Transient Dynamic Analysis
Get PDFThis research examines the influence of truncation error reduction on the nonlinear dynamic analysis of complex framed structures. A modified -adaptive method, incorporating inertial and damping forces in addition to the common restitutive forces, is introduced to refine the mesh and enhance accuracy. To address convergence challenges arising from increased complexity, Ritz modal shapes are utilized to reconstruct the mass matrix, excluding detrimental modes. The proposed formulation is validated through rigorous computational models and experimental data. Six building case studies, varying in complexity, were analyzed using the modified -adaptive method. The results revealed substantial variations in frequency and displacement responses, ranging from 6% to 50% and 0.8% to 63%, respectively. These disparities underscore the significant influence of nonlinear behavior on structures with high-order shape functions. The proposed formulation is theoretically more accurate. Therefore, the findings emphasize the necessity of employing mesh refinement techniques to obtain accurate nonlinear dynamic analysis results, particularly for complex structures with pronounced nonlinear characteristics. This study contains the background of a software called MainModelingStr. Doi: 10.28991/CEJ-2024-010-12-01 Full Text: PD
Assessing the Effect of Geometric Design and Land Use on Roundabouts Using Video Camera
Get PDFThis study is concerned with assessing the effect of geometric design and land use on roundabouts, which are one of the most widely used traffic calming techniques. It aims to study the speed profiles before, at, and after thirty selected roundabouts in Jordan to develop models for predicting the circulating speed for through movement as a function of the land use of the roundabout, the roundabout geometric characteristics, and the approaching highway free-flow speed. A laser radar gun was used to capture speed data, and geometric characteristics were extracted from video pictures. Various parameters were employed to simulate the circulating speed, including the roundabout diameters, free flow speed, entry deviation angle, approaching highway exit width, circulating roadway width, and entry width. Speed profiles were developed for six roundabout types with different land uses and geometric characteristics. It was found that the roundabout effect on speed reduction extends to 150 m downstream the exit and upstream the entry. It was also discovered that the rate of reduction varies according to the upstream street free flow speed (FFS), with dramatic decreases observed at the last 50 m upstream of the entry. Variability in the speed values around the midpoint of the circulatory roadway was observed, with speed at the exit being higher than that at the entry. Doi: 10.28991/CEJ-2024-010-11-012 Full Text: PD
Evaluating Axial Strength of Cold-formed C-Section Steel Columns Filled with Green High-performance Concrete
Get PDFConcrete-filled steel tube (CFST) columns that experience outward local buckling under high axial stress remain a significant concern, particularly when thin steel sections are used, as opposed to semi-compact and compact sections. This study investigated the performance of column systems by comparing single- and double-C-section configurations with both hollow and concrete-filled designs. Two types of infill materials were investigated: normal concrete and recycled material concrete, which included 10% waste glass powder as a cement replacement, 8% black high-density polyethylene beads as a sand substitute, and 10% pumice stone as coarse aggregate. To enhance the strength of the proposed CFS column, steel strips and screws were used to connect the flanges of the C-sections. Nine columns were tested experimentally under static axial load. Additionally, finite element analysis software was used to model and evaluate the effects of parameters beyond those investigated in the tests. The results indicated that the load capacity of the double face-to-face section was approximately 3% higher than that of the double back-to-back section. The addition of steel strips, used to connect the lips of the C-section flanges, enhanced the axial strength of the column by approximately 2% compared with the unstrengthened corresponding specimen and delayed buckling in the most vulnerable areas. Furthermore, the recycled infill concrete material had a minimal impact on the axial performance of the analyzed CFS columns compared to the control concrete, with a difference of less than 2.2%. The findings confirm that recycled waste material concrete can achieve performance comparable to that of the conventional concrete. Doi: 10.28991/CEJ-SP2024-010-014 Full Text: PD
Assessment of Mechanical Properties of Corroded Reinforcement in Chloride Environment Based on Corrosion Rate Monitoring
Get PDFExisting models for the evaluation of mechanical properties of corroded reinforcement, defined as a function of the mean cross-sectional loss or mass loss of the reinforcement, are not suitable in the case of chloride-induced corrosion, which causes irregular corrosion attack with pronounced localized damage”pits, whose geometry and spacing have a major influence on the mechanical properties of the reinforcement. Models that consider the irregularity of damage due to chloride corrosion are efficient, but as with models based on cross-sectional or mass loss, it is necessary to extract corroded rebars from the reinforced-concrete structure, which is a destructive procedure that can only be performed to a limited extent on an in-service building. To fill the above gaps, a new method based on the non-destructive measurement of corrosion parameters is proposed. The corrosion depth determined from the monitoring correlates directly with the remaining mechanical properties of the reinforcement; therefore, it is not necessary to determine the remaining cross-sectional area and geometry of the pits. The proposed models are based on experimental research on reinforced-concrete beam specimens subjected simultaneously to sustained loading and accelerated chloride corrosion in an environmental chamber in order to induce corrosion similar to that on real structures. Doi: 10.28991/CEJ-2024-010-11-02 Full Text: PD
Earthquake Resistance of Masonry-Infilled RC Frames Strengthened with Expanded Metal
Get PDFThis research aimed to investigate the compressive strength of lightweight concrete walls before and after reinforcement using the expanded metal reinforced with ferrocement jacketing method and to evaluate the performance level of lightweight concrete walls in reinforced concrete rigid frames. Masonry infill walls were tested using seven samples of lightweight concrete with an average size of 600í—600 mm under axial force. The study results were found that in the part of control, non-plastered lightweight concrete wall (CWL) bore an average compressive strength of 2.52 MPa, and plastered lightweight concrete (WPL) bore an average compressive strength of 2.95 MPa. It indicated that plastering on masonry infill walls was able to bear higher impact strength at 1.17 times due to the bonding force of plastering cement at the masonry infill wall. Lightweight concrete walls reinforced with expanded metal, which were able to bear the maximum compressive strength, were lightweight concrete walls reinforced with 1 layer of expanded metal (WPL-E1) that bore the maximum compressive strength capacity, which was equal to 6.40 MPa. When compared with plastered lightweight concrete walls (WPL) samples, masonry infill walls had 2.16 times higher strength capacity. It was shown that reinforcement using the ferrocement technique significantly increased compressive strength capacity. However, in this research, WPL samples, the plastered lightweight concrete walls, were selected as the control samples, and WPL-E1 test samples with the highest compressive strength were used to evaluate the performance level of the reinforced concrete rigid frame. It was found that lightweight concrete walls reinforced with expanded metal were able to bear higher strength at 1.92 and 3.66 times, respectively. When compared to unreinforced masonry infill wall samples and the bare rigid frame, reinforcement with expanded metal effectively was able to increase the strength and stiffness of the reinforced concrete rigid frame. Doi: 10.28991/CEJ-2024-010-12-017 Full Text: PD
Studying the Behavior of Expansive Soil Reinforced by Micropiles
Get PDFExpansive soil is a form of soil that can expand and contract, changing its volume. Montmorillonite, a mineral with the ability to dissolve in water, makes up the majority of these kinds of soils, and by increasing the volume of the soil, it causes the soil to heave. Expansive soils could be a substantial concern for engineered buildings due to their capacity to adjust to seasonal variations by contracting or expanding moisture content. Many researchers focused on soils that were swollen and looked at how they behaved as well as how they could be improved. In this study, the work depends on inserting micro-piles with different depths and configuration widths to investigate which depth and configuration can be obtained to improve the bearing capacity of foundations on expansive soil. The main purpose of this study is to reinforce the expansive soil with micro-piles with different depths (1B, 2B, and 3B) and different configuration widths (under footing only, 1B and 2B). It was concluded that the soil reinforced with micro-piles improved the load-bearing capacity of the expensive soil and decreased the swell pressure. The increasing depth of the micropiles 2B to 3B (B is the width/diameter of the foundation) can increase the bearing capacity by just 6%; therefore, increasing the depth beyond 2B is not beneficial. Also, the increase in width of the configuration of the micro piles from 1B to 2B increases the bearing capacity by just 4%; therefore, the increase in width greater than 1B is not valid. Doi: 10.28991/CEJ-2024-010-01-017 Full Text: PD
Examining Soil Microplastics: Prevalence and Consequences Across Varied Land Use Contexts
Get PDFIn an extensive exploration of microplastics within soil environments, our study aims to investigate the presence, spread, and ecological impact of microplastics in soil, focusing on Makassar City, Indonesia. Using a Sinher binocular digital microscope, we visually examined soil samples in Petri dishes, measuring microplastic sizes with Image-J software. Fourier-transform infrared (FTIR) spectroscopy was also employed for additional identification and analysis of polymer compositions. Our research uncovered a widespread presence of microplastics across diverse soil types and land uses, including residential, fishpond, agricultural, landfill, coastal, and bareland areas. The concentration of these microplastics was found to be between 16.6 to 21.9 particles/gram, showing consistency across most land uses, with some variations in coastal areas. We noted a significant variety in microplastic forms, predominantly fragments and films, across the different land uses. A wide range of colors was observed, including blue, green, red, and transparent. Polyethylene (PE) and polypropylene (PP) were identified as the predominant polymers. Our study highlights the non-uniform distribution of microplastics in soil, suggesting potential significant impacts on soil organisms and the wider ecosystem. These findings underscore the critical need for more comprehensive research on the ecological implications of microplastics in soil environments. Doi: 10.28991/CEJ-2024-010-04-017 Full Text: PD