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2007 research outputs found
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Shear Behavior of Random Rockfill in Dam Construction via Large-Scale In-Situ Testing
No full textDam construction commonly demands a massive amount of random material. This material offers practical material collection, minimum environmental impact, and economical cost. Unfortunately, shear strength assessment of random material is difficult because of large particle presence. Regular laboratory tests cannot accommodate these large particles. Misevaluation of random material shear strength may induce disastrous collapse. A large-scale direct shear apparatus, with a 70 cm by 70 cm shear plane, was developed and proposed for testing random fill material in-situ. This manuscript presents an experimental study using this device in Rukoh Dam construction, Indonesia. Test results captured variations between normal stress and shear stress to determine shear strength parameter models. Volume changes during shearing were also observed. Random materials in Rukoh Dam could be categorized as random rock. This study was also compared to other relevant rockfill studies. The proposed method offers an impressive approach for assessing and verifying the shear strength of compacted random material as well as compaction quality on site. It can be used to decide if the ongoing design and compaction method have to be modified or continued. Since the proposed direct shear test is reliable, fast, simple, and inexpensive, it is strongly recommended for dam construction
Enhancing Operating Rules for Water Pumping Stations Under Transient Flow Conditions by Using Surge Tanks
No full textWith an emphasis on Pump Station 1 (PS1) of the Basra Water Project (Open Canal) in Iraq, this study examines the essential hydraulic parameters of water pumping stations under transient flow situations. The study assesses the effects of routine operations, unexpected shutdowns, and surge tank installations on pressure stability and system flexibility using hydraulic modeling with HAMMER V8i. The findings show notable changes in pressure during brief occurrences. An abrupt shutdown without surge tank protection resulted in minimum pressures of 12.5 m in pipes L1 and L2, exposing them to hydraulic transient effects. The maximum pipe pressure under normal circumstances was 17.5 m (L3). Because of its exposure to low-pressure occurrences, the analysis identifies L1 as the most in-danger pipeline. It has been demonstrated that traditional operating procedures, which frequently ignore transient dynamics, increase the probability of service disruption and lead to inefficiency. In contrast, adding surge tanks reduces pressure variability and lessens the impacts of the water hammer, significantly increasing pressure stability, especially when three tanks are used. The results highlight how adaptable operational procedures are essential for employing and managing water delivery systems. According to the study findings, adding surge tanks improves durability and performance while lowering the risks of transient flow occurrences. This offers a guide for restructuring water pumping station operations
A Novel Approach to Selecting Rational Supports for Underground Mining Workings
No full textThe goal of this study is to examine the stress-strain state and stability of rock massifs to select a rational type of support for underground workings in challenging mining and geological conditions. The primary aims include increasing the speed of mine workings, reducing capital expenditure, and enhancing safety. Established and novel theoretical methods for mining, geomechanics, and rock massif management were employed. These methods involve analyzing factors affecting the mine working speed, studying the physical and mechanical properties of rocks, developing stratigraphic profiles, and assessing the stress-strain state and stability using Bieniawski's Rock Mass Rating (RMR), Barton's Q-rating, and construction norms and rules. Numerical modeling with the Rocscience RS2/RS3 software was utilized to identify failure-prone areas and determine rational support types and parameters. This study provides comprehensive insights into the stress-strain state of the massif, identifying high-risk zones, and recommending suitable support types. The findings contribute to accelerating the progress of underground work, enhancing safety, and reducing construction costs. The developed support systems for challenging mining and geological conditions were designed to increase the speed, safety, and profitability of underground workings. Additionally, this research emphasizes the significance of selecting appropriate support systems to ensure the longevity and stability of underground structures, thereby optimizing operational efficiency and cost-effectiveness. Doi: 10.28991/CEJ-2025-011-03-022 Full Text: PD
Development of Novel Surrogate Models for Stress Concentration Factors in Composite Reinforced Tubular KT-Joints
No full textCircular hollow section (CHS) joints are among the most critical components in offshore jackets, often requiring rehabilitation to maintain structural integrity. The structural stress approach, based on stress concentration factors (SCFs) for hot-spot stress (HSS) calculations, is commonly used to estimate the fatigue life of critical structural elements such as CHS joints. Various empirical models exist for the rapid estimation of SCF in composite-reinforced CHS joints; however, most studies focus on SCF at the crown and saddle positions under uniplanar loading. This limitation reduces their applicability to multi-planar loading conditions, potentially leading to the underestimation of HSS. This study investigates the use of fiber-reinforced polymer (FRP) composites to strengthen CHS KT-joints under complex loading, focusing on reducing SCF and improving fatigue life. A total of 5,429 finite element simulations were conducted to examine the effects of geometric and reinforcement parameters on SCF. The simulation data were used to train artificial neural networks (ANNs), which were incorporated into a computational tool for the rapid approximation of hot-spot stress in FRP-reinforced KT-joints. The application of composites to CHS joints significantly reduces SCF, particularly with an increased number of reinforcement layers, a higher elastic modulus, and an orthogonal fiber orientation to the weld toe. This study presents a novel methodology for developing efficient models to estimate SCF in composite-reinforced CHS joints under complex loading, addressing a key gap in fatigue design for such joints. The developed computational tool enables the rapid calculation of hot-spot stress in CHS joints. Doi: 10.28991/CEJ-2025-011-04-012 Full Text: PD
Effect of Signal Filtering on Metaheuristic-Based Structural Parameter Identification in Shear Building Models
No full textThis study evaluates the effectiveness of three metaheuristic algorithms—Genetic Algorithm (GA), Differential Evolution (DE), and Particle Swarm Optimization (PSO)—for identifying lateral interstory stiffness and the modal damping ratio in two-dimensional shear building models. The main objective is to estimate these parameters using time-domain displacement, velocity, and acceleration data, assuming known floor masses and unknown input excitation that primarily excites translational vibration modes. Three structural configurations with 2, 3, and 5 stories are analyzed to assess the scalability and robustness of each algorithm. To assess the effect of signal filtering on the performance of the algorithms, white noise is added to the synthetic response data at six levels ranging from 0% to 5% of the root mean square (RMS) amplitude. A sixth-order Butterworth filter is applied to evaluate the effect of signal preprocessing, and results obtained with and without filtering are compared. The results show that all three algorithms achieve acceptable levels of accuracy, even under noisy conditions. Filtering consistently improves identification accuracy, especially in high-noise conditions. In the most challenging case (5% noise, 5-story model), the average identification errors were 5.042% for GA, 5.106% for DE, and 5.035% for PSO. The findings underscore the practical value of integrating signal filtering with metaheuristic optimization for robust structural system identification in noise-contaminated environments. To account for the random nature of the algorithms, all results reported correspond to the average of 10 independent runs per identification scenario to ensure reliable performance evaluation
Experimental and Numerical Analysis of the Behavior of Steel Scaffolding
No full textIn recent days, due to the reduction in the labor force, investment in construction equipment has become increasingly common to compensate for the shortage of workers. Among other equipment, scaffolding”both external and internal”plays a crucial role during the construction phase of buildings. Scaffolds are among the components that require special attention, as they are directly linked to the health and safety of workers. For this reason, they have received significant attention in recent years following frequent collapse incidents. Any defect in the construction or use of scaffolding can pose serious, even fatal, risks to workers. Therefore, the safety and stability of scaffolds are essential for preventing accidents and protecting the lives of those working on construction sites, especially those working at great heights. This study analyzes scaffolding with a height of 200 cm, treating it in a spatial manner to calculate the maximum load-bearing capacity, lateral and vertical displacements, as well as to assess the stress and deformation states in the vertical elements (columns). This process was carried out by applying the rules of Eurocode EN 1993-1-1, along with experimental analysis and calculations using the SEIMOSOFT application software. Doi: 10.28991/CEJ-2025-011-05-014 Full Text: PD
Factors Influencing Performance, Durability, and Environmental Impact of Hydraulic Structures Using Waste Composite
No full textThis research explores the crucial elements influencing the impact of hydraulic structures constructed using waste-based composites, emphasizing sustainable material integration in infrastructure. A conceptual model comprising five constructs—Design and Structural Performance, Durability, Environmental Impact, Material Characteristics, and Waste Composites—was established and analyzed utilizing Partial Least Squares Structural Equation Modeling (PLS-SEM). Data was combined from 260 construction professionals across the key construction industry. G*Power analysis confirmed the lowest required sample size of 150; the larger sample enhanced statistical robustness. All constructs demonstrated strong reliability, convergent validity, and discriminant validity, with significant path relationships supporting the proposed hypotheses. Material Characteristics (β = 0.568) and Environmental Impact (β = 0.353) emerged as the most influential predictors of hydraulic structure performance. Empirical correlation, cross-loadings, HTMT, and VIF analyses confirmed model stability and construct independence. The results provide precious information for engineers, construction managers, and policymakers aiming to optimize structural integrity and environmental sustainability through the adoption of recycled composite materials. This research contributes to theoretical advancements in sustainable construction and provides practical implications for material selection, policy formulation, and infrastructure design. The study recommends future research on real-time performance monitoring, expanded geographic validation, and inclusion of cost-efficiency and technological integration variables
Sluice Gate Operation and Managed Water Levels Improve Predicted Estuarine Lake Water Quality
No full textSaemangeum Lake, an artificial estuarine lake, suffers from a pollutant load from an upstream watershed that is insufficiently mitigated by current load reduction measures. However, no studies have reported simulated flow direction and velocity for a lake. This study aimed to present an alternative solution based on managing water levels and sluice gate operation. Data were collected on water quality, sluice gate operation, water levels, tidal currents, and flow velocities. Next, the inflow and outflow volumes through the sluice gates were calculated. The Delft3D model was applied to predict water quality in a number of simulated scenarios. Finally, streamline and vorticity were calculated to evaluate hydraulic phenomena, while the ecology-based seawater quality index was employed to evaluate water quality. Analysis of flow characteristics revealed a large-scale clockwise vortex formed in the area where the Mangyeong River meets one of the sluice gates. It revealed a two-layer circulation with different flows in the surface and bottom layers. Evaluation of predicted water quality showed that one-way circulation, alternated in 15-day cycles, significantly improved major water quality items at most stations. Collectively, these findings demonstrate the effect that gate operation and managed water levels can have on the water quality of estuarine lakes. Doi: 10.28991/CEJ-2025-011-01-015 Full Text: PD
A Comparative Study of PCA and KPCA for Groundwater Quality Index Estimation
No full textGroundwater quality assessment is crucial for ensuring human welfare and promoting sustainable economic development. This study evaluates the effectiveness of linear Principal Component Analysis (PCA) and nonlinear Kernel PCA (KPCA) in developing a reliable Groundwater Quality Index (GWQI) for Qena, Egypt. Using ten hydrochemical parameters from seventy-three groundwater samples, we compare the performance of four kernel functions within the KPCA framework. The PCA-based GWQI classified 71.0% of samples as suitable for irrigation, closely aligning with the Wilcox Diagram classification (76.7%). In contrast, KPCA with linear, polynomial, sigmoid, and radial basis function kernels yielded suitability rates of 58.9%, 52.1%, 63.0%, and 58.9%, respectively. These values are consistent with USSL (53.4%) and Na% (53.4%) classifications. Notably, the sigmoid kernel in KPCA demonstrated stronger correlations with Key hydrochemical parameters, effectively capturing nonlinear data structures. These findings underscore the importance of accounting for nonlinearity in groundwater quality assessment and demonstrate the potential of KPCA to improve GWQI accuracy. This comparative analysis highlights KPCA’s superiority over PCA for nonlinear datasets, providing enhanced tools for groundwater management and more reliable quality evaluations
Web-Crippling Behaviour of Cold-Formed Screw Fastened Rectangular Hollow Flange Z-Section Beams Under Two-Flange Load Cases
No full textThis study investigates to update the web-crippling coefficients of cold-formed screw-fastened hollow flange Z-section (SFHZ) beams under End-Two-Flange (ETF) and Interior-Two-Flange (ITF) loading conditions. As coefficients are available in AISI standards to estimate the web crippling capacity of Z-sections, experimental program is carried out on 48 number of SFHZ specimens. An extensive parametric study considering the effects of web slenderness, material strength, and support length is conducted for 240 finite element models. Both experimental results and Finite Element Analysis (FEA) were used to predict web-crippling capacities and verified with current AISI predictions. The findings reveal that existing specifications are un-conservative for both ETF and ITF load cases. The parameters such as web height-to-thickness, inside bend radius-to-thickness, and bearing length-to-thickness ratios are the key factors influencing the prediction of web crippling capacity of SFHZ sections. As a result, the study proposes updated web-crippling coefficients that offer improved accuracy in predicting SFHZ section performance under two-flange loading conditions