2031 research outputs found
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Refining Low Strain Pile Integrity Testing for Minor Flaw Detection with Complex Wavelet Transform
Get PDFThe structural integrity of pile foundations is critical for the safety and longevity of buildings and infrastructure. Low strain impact testing is a widely used non-destructive method for assessing pile length and identifying significant defects; however, its sensitivity to minor flaws remains limited. This study aims to enhance the detection capabilities of low strain testing for minor defects by proposing an improved methodology. We conducted field tests on ten piles with small, artificially introduced flaws and complemented these tests with three-dimensional numerical simulations. Initial time-domain analyses of both field and simulated data, using low-frequency wave excitation, did not reveal distinct signal features indicative of defects. To address this limitation, we employed a set of hammers with varying weights and head materials for wave excitation, simulated with different input force pulse durations. We further applied Complex Continuous Wavelet Transform (CCWT) for time-frequency analysis of the acquired signals, which effectively identified minor defects through characteristic changes in wavelet coefficient phase angles at expected timestamps. The consistency of CCWT phase spectrum features across signals from different hammers, considering the varying sensitivities of wave excitations, facilitates the differentiation of genuine flaw-induced phase shifts from noise. The study's findings were integrated into an improved low strain pile integrity testing workflow, enhancing the method's accuracy in detecting minor flaws. Doi: 10.28991/CEJ-2024-010-10-05 Full Text: PD
The Behavior of the Tunnel Reinforced with Geogrid in Soft Soil Under the Effect of Axial Load
Get PDFThe soft soil's poor tensile strength requires reinforcing to increase bearing capacity, improve stability, and reduce settlements. This study assessed the efficacy of using geogrid layers to enhance and secure the soil surrounding tunnels. enabling the tunnel to endure pressure, particularly during excavation. The utilization of geogrids in soil reinforcement has experienced a substantial rise as a result of their consistent dimensions and exceptional tensile strength. To quantify the exerted force transferred to the tunnel, during this study utilized various testing tools, including a soil container, a steel loading frame, data loggers, a 0.5-ton load cell, and a miniature pressure cell. The vertical loads are applied by utilizing a hydraulic jack. A series of eleven tests were conducted on the tunnel at two depths of 1.5D and 2.5D, where D is the tunnel's diameter. The different models of geogrid layers showed that using two layers of geogrid at the first dimension, 0.5B and 1B from the base, led to a significant increase in tunnel stability. Two layers of reinforcement were used in both directions, giving the soil a high bearing capacity for the loads applied to the tunnel. This resulted in an improvement, a 1.65 in 1.5D and a 1.82 in 2.5D. The pressure above the pipe decreased by approximately 7.1kPa at the first tunnel depth and about 3.5kpa at the second depth. In conclusion, the study found the geogrid improves the stability of the tunnel by equally distributing loads and minimizing stress concentrations, hence decreasing the chances of collapses or deformations. Doi: 10.28991/CEJ-2024-010-08-04 Full Text: PD
Effect of Porous Rectangular Type Baffle Block Angle on Hydraulic Jump Downstream of Spillway
Get PDFThe 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 Challenges of Implementing Cognitive Computing in Small Construction Projects: A Data-Driven Perspective
Get PDFThis 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
Analyzing the Future Climate Change Impacts on Meteorological Parameters Using the LARS-WG Model
Get PDFThis research aims to evaluate the impacts of climate changes and reveal the future trends on meteorological parameters, i.e., precipitation and temperature effects, in three major cities in Iraq, namely Baghdad, Wasit, and Maysan, which are located along the Tigris River basin. The LARS-WG8.0 model was employed, and five GCMs were used within CMIP6 under three different scenarios, i.e., SSP126, SSP245, and SSP585, for the period 2021-2100. The observed and simulated data were tested by the statistical criteria R, R2, NSE, and RMSE through the baseline period 2003-2022. In addition, using the K-S test for validation of the LARS-WG8.0 model resulted in accuracy and reliability. The future projections indicate that the average temperatures will increase until the end of the current century, with a difference of 1.86, 2.85, and 5.36°C. The fluctuations in precipitation occur throughout the winter, spring, and autumn months. The highest precipitation was recorded in December and January. Therefore, all GCMs give a unified indicator of future climate forecasts. Rising temperatures and fluctuations in precipitation negatively impacted water and food security. As a result, this will impact the water resources and agricultural sectors. This research contributes to exploring the future climate behavior of the study area. Doi: 10.28991/CEJ-2024-010-11-019 Full Text: PD
Evaluation and Restoration of Corrosion-Damaged Post-Tensioned Concrete Structures
Get PDFThis study addresses the pressing issue of chloride-induced corrosion in post-tensioned (PT) concrete structures, known for their strength and flexibility yet vulnerable to durability issues in extreme climates. The objective is to evaluate corrosion mechanisms in a PT building in the United Arab Emirates and develop a robust restoration strategy. Using a combination of nondestructive and semi-destructive testing methods, this research identifies severe deterioration in critical structural elements, such as steel tendons, PT ducts, and concrete surfaces, largely due to high chloride exposure and aggravated by environmental factors like acid rain and fluctuating temperatures and humidity. The findings reveal serious inadequacies in current maintenance practices, often overlooking long-term corrosion risks in harsh climates. In response, this study proposes a comprehensive repair strategy, including removing damaged materials and applying advanced repair products, protective coatings, and waterproofing measures to enhance the structure's durability. This case study highlights significant concerns regarding structural integrity and provides practical insights into effective maintenance and repair strategies for PT structures. By offering a targeted, sustainable intervention approach, this research contributes to developing PT maintenance protocols, particularly in regions prone to aggressive corrosion, ensuring the longevity and safety of these critical structures. Doi: 10.28991/CEJ-2024-010-12-02 Full Text: PD
Experimental Study on Strength and Performance of Foamed Concrete with Glass Powder and Zeolite
Get PDFCement manufacturing accounts for approximately 7% of anthropogenic CO₂ emissions. To mitigate environmental impact and achieve "net zero” by 2050, developing cementitious materials that minimize cement consumption is crucial. This research aims to reduce cement usage in Foamed Concrete (FC). The study investigates the mechanical, durability, and thermal properties of FC using two distinct Supplementary Cementitious Admixtures (SCA): Glass Powder (GP) and natural zeolite. Cement was replaced with SCA at varying percentages (0%, 5%, 10%, 15%, 20%, and 25% by weight) in FC. The FC density was adjusted by incorporating foam at 15% and 30% of the total volume of concrete. The study evaluated the flowability of each mix in its fresh state. The mechanical properties were assessed by measuring compressive strength and ultrasonic pulse velocity. The performance of FC was further analyzed in terms of thermal conductivity, sorptivity, and water absorption. The test results revealed that FC with GP combinations exhibited high flowability and an improved strength-to-density ratio. Additionally, water absorption, sorptivity, and thermal conductivity were significantly reduced compared to conventional FC. An extensive cost-benefit analysis highlighted the feasibility of utilizing common waste materials to produce high-grade FC and assessed the impacts of cementitious admixtures as viable alternatives to cement. Doi: 10.28991/CEJ-2024-010-12-06 Full Text: PD
Assessing the Self-Report Instruments of Younger Versus Older Riders Involved in Near-Miss Motorcycle Incidents
Get PDFRoad accidents pose severe and pervasive consequences, especially in low- and middle-income countries (LMICs), where both the population and fatal accidents among youth and the elderly are steadily increasing. Therefore, this study aims to develop a model for risky behavior in near-miss incidents among motorcycle riders in Thailand. It intends to compare models between younger and older riders utilizing structural equation modeling (SEM) with a multi-group approach. The data were examined employing modified instruments derived from the Motorcycle Rider Behavior Questionnaire (MRBQ). Samples depicting risky riding behavior were obtained from both younger and older rider groups. Parameter invariance testing revealed differences between the two groups. Control errors notably emerged as the predominant factor contributing to near-miss incidents for both age groups. Speeding was identified as the primary concern for the younger group, while adverse weather conditions were deemed crucial for the older group. Based on this study, policy recommendations endorse the creation of targeted training programs for novice riders, emphasizing adherence to legal speed limits and the adoption of safe riding practices. Additionally, the study underscores the importance of preparing riders, especially those in the older age group, for adverse weather conditions. Doi: 10.28991/CEJ-2024-010-02-019 Full Text: PD
Rice Self-Sufficiency and Optimization of Irrigation by Using System Dynamic
Get PDFThis research intends to optimize the results of irrigation canals with the conversion of function to fisheries without reducing rice self-sufficiency regionally. However, irrigation is an infrastructure asset that needs to be used optimally. It is due to the water; water sources and irrigation infrastructure can provide more benefits to rice fields, which are to function as fisheries in the study location (West Sumatra Province). The aim of this research is to propose the optimal combinations of irrigated land planted with rice and those in the form of fisheries. The methodology uses System Dynamics due to the official BPS data. There are many tools that are used in this system dynamics approach, such as causal diagrams, archetype systems, diagrams of stock and flow, and the behavior of over-time graphs. The DSS generator for simulating the program in this study uses Stella, which is a new paradigm in the water resources system approach. The result shows that the potential increase in income that could be obtained by converting the rice fields to tilapia fisheries is about 126 million Rupiah per year per hectare. West Sumatra Province, as a national rice granary, has many districts that are more self-sufficient in rice, so it can be considered to utilize irrigation to become the irrigation for fisheries. The potential of rice fields that can be converted into fisheries while maintaining self-sufficiency in rice at the district/city level of West Sumatra Province is more than 61 thousand hectares, and it generates an increase in income of about 7.7 trillion per year. Doi: 10.28991/CEJ-2024-010-02-010 Full Text: PD
Valuation of Urban Green Open Spaces Using the Life Satisfaction Approach
Get PDFThis study conducts the valuation of the urban Green Open Spaces (GOS) in Jakarta (Indonesia) using the life satisfaction approach (LSA). We integrated the important elements of the LSA, such as housing structure and environmental facilities, into a comprehensive valuation model (using hedonic variables). By explicitly acknowledging the limited application of these methodologies in developing nations, this study endeavors to provide a context-specific understanding of the economic value of GOS in Jakarta. The LSA model, a novel non-market valuation tool, employs community life satisfaction as its primary metric. In this study, we analyzed the satisfaction levels of residents of Jakarta based on a 10-point scale; the responses of a total of 1,592 participants were collected through online questionnaires in 2021 (during the pandemic). We considered various independent variables, including socioeconomic factors, housing attributes, environmental facilities, location amenities, and the presence of GOS. The analysis involved LSA and ordinary least squares (OLS) models in the Statistical Package for the Social Sciences (SPSS). The results indicate that several variables, such as longer residence duration, good employment status, high income "over 20 million Indonesian Rupiah (IDR); approximately USD 1281.56”, and access to more shopping centers, positively influenced the life satisfaction of the residents, which is in line with the studies conducted in western countries. Surprisingly, the economic evaluation of urban GOS portrayed a limited impact on the residents' life satisfaction, while negative aspects, e.g., the presence of cemeteries around residential areas (19.1%), impacted the residents significantly. Urban parks did not portray statistical significance in influencing the residents' life satisfaction, despite having a positive impact across all radii of urban regions. Urban forests exhibited a positive impact, mainly within the 100–500-m radius, with a significant impact on resident life satisfaction. Our attempt to assess the values of landscape amenities in Jakarta using LSA marks a pioneering effort in the field of environmental science with respect to community preferences. Consequently, this study contributes significantly to the evolving yet limited literature in this domain. The results differ from those of the Global North research, emphasizing the need for context-specific urban planning strategies. Our study offers valuable insights for urban planners and government entities and can guide GOS development to enhance urban sustainability and community satisfaction. The implications extend to urban centers in Indonesia and other developing countries, emphasizing the importance of optimizing limited urban spaces based on community preferences. Doi: 10.28991/CEJ-2024-010-04-010 Full Text: PD