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2007 research outputs found
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Evaluation of Hydraulic Structures for Agricultural Discharge Optimization
No full textThe objective of the research was to evaluate the hydraulic structures on the Al-Gharraf River in southern Iraq and their ability to achieve the required discharge for agricultural areas that depend on them. Al-Gharraf head regulator discharges unstable volumes of water, ranging from 280 m3/s in winter to 100 m3/s in summer. The research aimed to determine whether the operational discharges are achievable for the offtakes branching from the Al-Gharraf River when the river's discharge ranges from 60% to 100% of the operational discharge. The researchers utilized a simulation of the irrigation channel (SIC) model to simulate river flow. The researchers used hydraulic indicators such as Delivery Performance Ratio (DPR), Discharge Deviation (∆Q), and Sensitivity (S) to evaluate the work of the hydraulic structures (regulators), determine the more and less efficient regulators in delivering water to the offtakes, and determine the reasons for inefficiency. Depending on the discharge values for each offtake from simulation results by SIC and calculating the hydraulic indicators, it is observed that some offtakes exceed their operational discharges, such as Al-Zydia and Al-Sabila. Also, some offtakes do not receive their operational discharge (Al-Dawaiya, Shatt Al-Shatra, and Al-Basra) projects, which failed to reach even 10% of their operational discharges. The researchers suggest redesigning some offtakes and ensuring reasonable control of gate openings for other offtakes to make the water distribution proportional. Doi: 10.28991/CEJ-2024-010-05-010 Full Text: PD
Effective Stiffness and Damping Analysis of Steel Damper to Lateral Cyclic Loading
No full textSteel dampers are components used in building structures to reduce vibration and energy generated by dynamic loads such as earthquakes. Several factors affect the effectiveness of steel dampers in reducing energy, including the cross-sectional area, mass distribution, cross-sectional geometry, and material stiffness. The cross-sectional geometry or shape of the steel damper can affect how energy is absorbed and dissipated in the structural system. Cross sections with different geometric variations can have different mechanical responses to dynamic loads. This study aims to analyze which type of steel damper is effective in terms of stiffness and damping capacity against lateral cyclic loads. The steel damper cross-sectional variations used are slit steel dampers (SSDs), tapered steel dampers (TSDs), and oval steel dampers (OSDs). Cyclic testing of the dampers used displacement control with the same target deviation for all three damper types. The results showed that the stress and strain distributions of the oval steel damper were more even than those of the other two models. The variations in the energy dissipation capacities of the three cross-section variations are relatively the same. However, the slit steel damper type has the best stiffness compared to the other two types. This research is ultimately expected to influence the science of the structure of a building in preventing and anticipating earthquakes or other disasters. Doi: 10.28991/CEJ-2024-010-07-017 Full Text: PD
Experimental Study on the Effect of Flow Velocity and Slope on Stream Bank Stability (Part I)
No full textThe erosion of riverbanks is a significant and capricious national concern. The Al Muwahada channel in Iraq experiences instability in its banks, resulting in failure, retreat, and morphological alterations. These issues are mostly caused by factors such as the velocity of the flow, the angle of the slope, and type of soil. This study investigated the behavior of canal bank soil in response to erosion and variations in slope angle. Therefore, a physical model of a case study was established in the laboratory. Additionally, a slope angle of 26Ëš is being utilized, which has not been previously studied in the laboratory. This angle will be tested with five different velocity values: 0.101 m/s, 0.116 m/s, 0.12 m/s, 0.13 m/s, and 0.135 m/s. The bank's deformation was measured for a period of 12 hours, which was divided into 4 equal intervals for each velocity. The study determined that a riverbank with a slope of 26Ëš is more resistant to erosion when the velocity of the water is below 0.12 m/s. Velocities equal to or greater than 0.12 m/s have a substantial impact on the erosion of the riverbed. According to this study, a velocity of 0.12 m/s or higher leads to increased erosion of the riverbank. This is equivalent to a velocity of 0.804 m/s in the prototype channel. The section of the riverbank that has suffered the greatest damage due to erosion is the upper two-thirds. The used methodology supports global efforts to increase information about the behavior of river banks with unexplored rivers that have different flow velocities and bank slope angles. Doi: 10.28991/CEJ-2024-010-08-013 Full Text: PD
Assessing Geospatial Accuracy in Mapping Applications: A Focus on Google Earth
No full textGoogle Earth, among other online mapping platforms, offers an interactive mapping platform that has become indispensable for academic and research applications. It serves as a primary reference and a foundational tool for map creation, providing open-source, cost-free imagery that meets the user needs of the mapping community. As a contemporary repository of high-resolution images of Earth's landmass, Google Earth has vast potential for scientific exploration and remains an underexploited resource. Its rapid expansion and consistent reliability make it a favored source for mapping and routing tasks. However, this research underscores the crucial aspect of Google Earth's positional accuracy, which is at the heart of this study. A comparative analysis between the positional accuracy of Google Earth and traditional ground surveying maps was conducted. The Wilcoxon rank test and quantitative methods were used to evaluate coordinate discrepancies, revealing significant discrepancies between the two datasets. This study aims to provide a rigorous assessment of Google Earth's utility and accuracy in scientific and academic contexts, emphasizing its role and reliability as a critical resource for researchers and practitioners in the field of mapping. The results revealed displacement changes in both the northing and the easting coordinates. For the northing coordinates, the displacement increases when moving eastward and decreases when moving westward. For the easting coordinates, the displacement increases when moving northward and decreases when moving southward. This pattern highlights spatial discrepancies and the varying impact of location on the dataset's accuracy, emphasizing the need for targeted corrections to enhance data accuracy. These key findings provide valuable insights that could significantly contribute to optimizing mapping practices and efficiently exploiting this vast, yet underexplored, digital resource. Doi: 10.28991/CEJ-2024-010-08-012 Full Text: PD
The Effectiveness of the Procurement at the Construction Services Selection Implementation Center
No full textThe construction industry still faces various challenges in some developing countries, and one of the problems is the procurement of goods and services. The allocation of public procurement funds is significant to the national GDP. It is essential to conduct comprehensive research on government procurement in the construction industry in Indonesia due to the rapid growth of the construction industry in the last decade. This research focuses on the procurement of construction goods and services in the Ministry of Public Works and Housing by looking at the perception of the government as the project owner. This research aims to identify a model of critical success factors to improve public procurement performance in the construction industry from the government's perspective. The research method includes two stages, namely, the development of critical success, which consists of crucial factors and indicators that affect the performance of public procurement in the construction industry. It is a literature study of relevant previous research results from various countries that affect these critical success factors. Then, the second stage is a survey of experts' perceptions through questionnaires. The questionnaire data analysis used SEM-PLS software to quantify the relationship model of critical success factors to improve the performance of government procurement of goods and services in the construction industry. Data processing results include: business process factors affect 97.1%, regulatory factors affect 90.1%, information system factors affect 63.1%, human resource factors affect 56.1%, organizational factors affect 46.1%, and monitoring and evaluation factors affect 38%. Doi: 10.28991/CEJ-2024-010-03-013 Full Text: PD
Sustainable Concrete Production: Utilizing Cow Dung Ash and Corn Stalk Ash as Eco-Friendly Alternatives
No full textThis study aims to determine whether it is feasible to replace conventional materials used in manufacturing concrete with waste materials, namely cow dung ash and corn stalk ash. This study proposes to assess the possibility of using these agricultural by-products to improve the sustainability of concrete while simultaneously tackling the environmental issues related to the manufacture of conventional concrete. The research aims to assess the mechanical qualities, optimize the mix proportions, and examine the ecological implications of using these substitute materials. This research aims to mitigate environmental challenges like carbon dioxide emissions, resource depletion, and the accumulation of agricultural waste by combining agricultural waste and lowering dependency on traditional cement. The study investigates the use of cow dung ash (CDA) and corn stalk ash (CSA) as alternatives for conventional Portland cement (OPC) in mortar mixes at varying quantities, ranging from 5% to 25% CDA and 2.5% to 10% CSA. Chemical composition reveals that CDA and CSA predominantly comprise O, Mg, Al, Si, P, K, and Ca. The workability, hardened characteristics, and microstructure of CDA and CSA were assessed. Increasing CDA and CSA percentages reduced mortar workability; nevertheless, replacing 8% to 10% CDA and 7.5% CSA maintained compressive, tensile, and flexural strengths comparable to control mixes. However, more significant CDA and CSA proportions resulted in lower mortar strength. For example, 10% CDA-enriched mortar had a compressive strength of 31.77 N/mm2, a tensile strength of 3.42 N/mm2, and a flexural strength of 3.61 N/mm2, whereas 7.5% CSA-enriched mortar had a compressive strength of 28.4 N/mm2, a tensile strength of 3.04 N/mm2, and a flexural strength of 3.7 N/mm2. According to the findings, CDA and CSA can replace OPC by up to 10% and 7.5% in mortar manufacturing, making cementitious material alternatives viable. Doi: 10.28991/CEJ-SP2024-010-02 Full Text: PD
Enhancing the Properties of Steel Fiber Self-Compacting NaOH-Based Geopolymer Concrete with the Addition of Metakaolin
No full textThere is a demand for innovative construction materials that offer enhanced mechanical characteristics while also being cost-effective and environmentally friendly. This paper examines the fresh properties and mechanical properties of geopolymerized self-compacting concrete (SCC) reinforced with steel fibers, containing 0–100% metakaolin (MK) by mass, as an eco-friendly substitute for Portland cement. SCC combinations included one or more waste cementitious materials (WCMs), such as metakaolin (MK), NaOH as an alkaline activity, and double-hook end steel fibers. For every NaOH geopolymer SCC blend, the mechanical characteristics (compressive strength, splitting tensile strength, flexural strength), as well as the new properties (lump flow, V-Funnel, L-box test), were read up. The findings indicate that combining metakaolin and steel fibers reduces the flowability of NaOH-based geopolymer SCC. On the other hand, incorporating MK and steel fibers enhances the compressive and flexural strength of NaOH-based geopolymer SCC with 25% metakaolin and 0.3% steel fiber. In contrast to the fiber-reinforced NaOH-based geopolymer SCC samples, which could transfer a sizable load even when the crack mouth opening deflection rose at flexural strength, the fiber-free SCC samples showed a brittle and abrupt fracture. The findings showed that the addition of NaOH as an alkaline activator, MK, and steel fiber had a negative impact on the fresh state properties; however, their combined use greatly enhanced the bond strength and flexural performance of the NaOH geopolymer SCC specimens. Doi: 10.28991/CEJ-2024-010-07-011 Full Text: PD
Enhancing Soil Stability through Innovative Microbial-Induced Calcium Carbonate Techniques with Sustainable Ingredient
No full textExpansive soil poses significant challenges for civil engineers, leading to structural damage, particularly in lightly loaded structures. This study employs an innovative and sustainable recipe to stabilize highly expansive soil using the Microbial-Induced Calcium Carbonate Precipitation (MICP) technique by substituting conventional ingredients with olive mill wastewater and hydrated lime. A series of laboratory tests were performed to evaluate the improvement in Atterberg's limits, Free Swell, Unconfined Compressive Strength (UCS), and pH, in addition to a series of qualitative measurements, including X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Optical Microscopic Images, and bacteria growth rate. Different mellowing periods and different cementation concentrations were used. The proposed recipe results showed a 50% reduction in the soil's free swell value. The UCS of the treated soil using the proposed recipe was eight times that of the untreated soil and twice that of the soil treated with the traditional recipe. The SEM images showed flocculation and aggregation in the soil particles, with the voids becoming smaller and filled with calcium carbonate (CaCO3). The XRD results showed the formation of new CaCO3particles. The optimized recipe demonstrated remarkable enhancement improvement and significant changes in soil physical properties and microstructure. Doi: 10.28991/CEJ-2024-010-08-08 Full Text: PD
Adaptive Seismic Upgrading of Isolated Bridges with C-Gapped Devices: Model Testing
No full textThe seismic safety margins of seismically isolated bridges have not been thoroughly studied or comprehended due to a lack of actual on-site data observations. This study introduces a newly validated method for the efficient seismic protection of bridges that may be exposed to extremely strong, multidirectional near-source and critical far-source earthquakes. The isolated system was improved by incorporating innovative adaptive horizontal C-multigapped (HC-MG) energy dissipation devices to overcome the safety limitations associated with solely using isolated bridges under seismic loads. The newly developed adaptive C-gapped (ACG) bridge system was systematically validated through extensive experimental seismic tests on bridge models and additional analytical studies. The new ACG bridge system represents an advanced technical solution that integrates the benefits of seismic isolation and energy dissipation. The seismic isolation system for the large-scale ACG bridge prototype was designed using double spherical rolling seismic bearings (DSRSB). The seismic performance of the system was enhanced with adaptive HC-MG energy dissipation devices. The improved seismic performance of the system was demonstrated through extensive seismic shaking-table tests on the ACG bridge prototype, simulating selected seismic inputs characteristic of typical near- and far-source earthquakes. Doi: 10.28991/CEJ-2024-010-09-01 Full Text: PD
The Challenges of Implementing Cognitive Computing in Small Construction Projects: A Data-Driven Perspective
No full textThis study aims to identify and analyze the challenges of implementing cognitive computing in small construction projects, where decision-making, process optimization, and sustainability enhancements are crucial yet challenging. The research adopts a mixed-methods approach, integrating a thorough literature review, quantitative evaluation, and structural equation modeling (SEM) to explore the relationships between the identified barriers and the effective application of cognitive computing. The findings reveal significant hurdles, including complexity in customization (β = 0.327, t = 9.848, p < 0.001), data integrity and integration issues (β = 0.389, t = 14.534, p < 0.001), financial and cultural constraints (β = 0.295, t = 7.850, p < 0.001), and ethical and privacy concerns (β = 0.319, t = 8.963, p < 0.001). These barriers impede the seamless adoption of cognitive computing technologies. This research contributes novel insights into the specific challenges faced by small construction projects and provides practical recommendations to overcome these obstacles. By addressing these challenges, this study offers valuable guidance for stakeholders aiming to leverage cognitive computing to improve project outcomes in the construction industry. The novelty of this research lies in its focus on small-scale projects, a relatively underexplored area, and its comprehensive analysis of the multifaceted barriers that hinder the successful implementation of cognitive computing. Doi: 10.28991/CEJ-2024-010-09-011 Full Text: PD