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Numerical Analysis on Fatigue Performance in Fillet Weld Roots of Steel Bridge Bearings
No full textFillet weld roots near bridge supports are critical fatigue-prone details in steel bridges, particularly under high stress concentration. Fatigue cracks at these locations tend to be initiated internally, where detection and repair remain challenging with current techniques. Fatigue performance improvements are explored from the perspectives of structural design and epoxy insertion. Five actual bridges in the USA, China, and Japan were analyzed using a hybrid finite element modeling approach, employing low-precision girder models for load distribution and high-precision local support models with an introduced notch for Effective Notch Stress (ENS) evaluation. Both actual bridge case studies and numerical parametric analyses were conducted. Results indicate that increasing weld size effectively reduces ENS, while sole plate thickness has a limited effect. Bolts play a pivotal role in limiting relative displacement between the bottom flange and the sole plate, though their constraint range is localized. To address the limited effectiveness of structural adjustments, adhesive filling was introduced in areas beyond the bolt constraint range. Bonding-assisted welding with epoxy insertion achieved up to a 56% reduction in ENS and significantly improved fatigue performance. The findings confirm the potential of bonding-assisted welding for improving the durability of fillet weld roots in steel bridge supports and provide practical solutions to the difficult-to-detect root fatigue cracks
GPR-Driven Geomechanical Modeling and Drill-Blast Optimization for Enhanced Efficiency in Open-Pit Gold Mining
No full textThis study seeks to raise the operational efficiency and economic return of the Vasilkovskoye open-pit gold mine by integrating real-time ground-penetrating-radar (GPR) monitoring, geomechanical modeling, and digital optimization of drilling-and-blasting parameters. Continuous GPR scanning identified hazardous fracture zones that were subsequently characterized in DIPS and RS2 to model slope stability, while ShotPlus-based blast simulations and OrePro 3D displacement modeling guided the redesign of hole spacing, charge distribution, and delay timing. Fragmentation quality was verified with high-resolution photogrammetry and correlated to blast design through statistical analysis; a comparative techno-economic assessment quantified cost and dilution differentials between conventional and optimized schemes. The integrated workflow established a robust predictive link between blast geometry and fragment size, reducing oversize generation by 17% and ore dilution by 9%, while increasing gold grade in mill feed from 0.84 g t⁻¹ to 0.94 g t⁻¹. GPR-informed hazard mapping eliminated unplanned wall failures, and the revised pattern lowered specific explosive consumption without compromising fragmentation, cutting total unit costs by 8%. Unlike previous studies that treat slope stability and blasting as separate tasks, this study couples deformation dynamics with blast design in a single digital loop, offering a transferable framework for automation-ready, risk-aware mine planning at complex geological sites
Climate Change Impacts on Rainfall Variability and Adaptive Reservoir Operation in a Multi-Reservoir System
No full textChanges in rainfall patterns driven by climate change have altered the hydrological regime of river basins, creating substantial challenges for water resources management, particularly in the operation of the Batutegi cascade system comprising the Batutegi Dam, Way Sekampung Dam, Argoguroh Weir, Margatiga Dam and Jabung Weir. This study assesses the impacts of climate change on rainfall intensity, dependable flow, and water allocation modeling within the Sekampung River Basin. The analysis employed five rainfall datasets downscaled from the NASA Earth Exchange Downscaled Climate Projections at 30 arc-seconds (NEX-DCP30) and simulated using five CMIP6 models for both the historical period (1980–2014) and future projections (2024–2100). Results indicate that CMIP6 projections reproduce rainfall patterns reasonably well during January–February and May–July, but perform less consistently in March–April and October–November. Most models tend to overestimate the mean annual rainfall. Rainfall variability contributes to pronounced fluctuations in river discharge, particularly during the dry season. Dependable flows show marked changes, especially within the exceedance probability range of Q10% to Q100%. Although an overall increasing rainfall trend is observed, the system is still able to satisfy water demand under the 2023 operating rules, with potential deficits persisting during critical periods. Optimization modeling further demonstrates the necessity of adaptive reservoir operation rules under climate change, which could improve the reliability of meeting multisectoral demands to approximately 80%. These findings underscore the importance of incorporating climate model projections into watershed-based water resources management to strengthen resilience against extreme hydroclimatic variability
Performance Evaluation of Semi-Precast Reinforced Concrete Slabs Under Flexural Load
No full textThis study aims to evaluate the flexural performance of semi-precast reinforced concrete slabs incorporating steel lattice girders as internal reinforcement. The objective is to investigate the influence of geometric and material parameters such as precast slab thickness, lattice girder height, top chord diameter, concrete compressive strength, and the addition of steel or glass fibers on overall flexural capacity and deformation behavior. Thus, previous studies have shown that replacing conventional cast-in-situ slabs with semi-precast systems can reduce total construction costs by 43–70%. Thirteen semi-precast slabs and one control slab were tested under four-point bending, and a nonlinear finite element model was developed in ABAQUS to simulate the experimental response. The analysis focused on load–deflection behavior, strain distribution, and failure modes. Results indicated that increasing slab thickness and chord diameter enhanced stiffness and load-bearing capacity, while higher concrete strength and fiber reinforcement improved crack control and reduced deflection. The FEM model demonstrated strong agreement with experimental results, validating its reliability for predicting structural performance. This study extends previous research by integrating a broad experimental parameter range with a validated ABAQUS finite element model, providing new insights into the structural optimization and cost efficiency of semi-precast slab systems. The proposed semi-precast system exhibited ductile behavior and achieved savings in formwork and labor cost compared with conventional flat slabs, offering a practical and sustainable alternative for efficient concrete construction
Passive Earth Pressure Analysis for Unsaturated Soils on Retaining Walls Incorporating Arching Effect
No full textRetaining structures in geological and geotechnical engineering are often embedded in unsaturated soil strata. Conventional methods for calculating earth pressure in unsaturated soils typically ignore the rotation of principal stresses in the backfill, a phenomenonknown as the soil arching effect. This study presents a novel analytical framework for determining the passive earth pressure in unsaturated soils that explicitly incorporates this arching effect. The proposed model accounts for both principal stress rotation and the hydro-mechanical coupling between matric suction and soil stress under groundwater influence. Based on the shear strength criterion for unsaturated soils, the model assumes a circular-arc trajectory for the rotating major principal stress, and hydrostatic seepage with matric suction distributed linearly with depth. Using a coordinate axis translation technique, quantitative relationships among lateral earth pressure, interlayer shear stress, and vertical stress are established. The force equilibrium equations for a horizontal differential soil element are then solved to derive closed-form expressions for the passive earth pressure distribution and resultant force. Validation against physical model tests and numerical simulations confirms the model’s accuracy and demonstrates its superiority over the extended Rankine theory, which systematically underestimates passive resistance. Parametric studies highlight the influences of groundwater depth, initial matric suction, and soil strength parameters. The proposed framework offers a more realistic and mechanically sound basis for the design of retaining structures in unsaturated soil environments
Interaction of Life Cycle Assessment (LCA) and BIM in a Construction Project to Reduce the Environmental Footprint
No full textThe construction sector is experiencing rapid growth in response to the increasing demand for new projects that address societal needs, making it one of the most significant contributors to greenhouse gas emissions. Therefore, it is essential to develop more sustainable and efficient construction processes that reduce the environmental impact in the sector. This study focuses on assessing the environmental footprint of a residential project in Colombia, based on the implementation of Building Information Modeling (BIM) with a sustainability focus. A Life Cycle Assessment (LCA) was performed using the "One Click LCA" software, where the characteristics of the building over a 50-year period were inserted and evaluated. The study determined the building's environmental impacts and direct pollutant emissions, including global warming (CO2e), acidification (SO2e), eutrophication (PO4e), and ozone depletion (CFC), among others. The results were analyzed by evaluating their magnitude and criticality. One of the main findings was the emission of 1.49E+06 kg of CO2, which directly impacts global warming significantly. This LCA-BIM approach provides a transparent methodology for construction companies in Latin America to implement projects with a lower environmental impact, promoting sustainable practices within the industry. Doi: 10.28991/CEJ-2025-011-01-08 Full Text: PD
Assessment for Evaluation of Local Roads Based on Infrastructure Data and Budget Allocation
No full textTechnical criteria are one of the determining factors in calculating the technical index amount of the allocation budget for road infrastructure. The technical criteria include pavement deterioration, bridge condition, road performance, local budget allocation for road capital expenditure, allocation of local budget government for routine maintenance of roads, e-monitoring reporting, and SHP map reporting. Evaluation is required to determine the influence of each of these criteria and highlight the importance of comprehensive and continuous data testing to provide an overview of road infrastructure data and budget allocations. This study aims to analyze the influence of each technical criterion based on infrastructure data and the allocation of funding for local road maintenance in Indonesia. Two regression methods, Multiple Linear Regression with Dummy (MLRD) and Binary Logistic Regression (BLR), were used to identify and evaluate each variable and the potential of the resulting criteria. The results show that pavement deterioration (PD) and road performance (RP) are the criteria that significantly influence the assessment of infrastructure data and are the best models. This finding highlights the need for comprehensive data testing to provide an accurate overview of local road infrastructure from the data submitted by local governments to the central government. Doi: 10.28991/CEJ-2025-011-01-04 Full Text: PD
Artificial Recharge of an Unconfined Aquifer Using Treated Wastewater as a Climate Change Mitigation Strategy
No full textWorldwide groundwater extraction has increased dramatically during the past six decades. Water scarcity will affect 1.4 billion people in around 48 nations by 2025. Iraq is experiencing an unparalleled and severe water crisis due to various factors, including climate changes, insufficient rainfall, the policies of neighboring nations, and the increased demand resulting from population expansion. The research area (Dibdiba aquifer) is in Iraq, in the middle between Najaf and Karbala. It was observed that farmers had abandoned numerous wells as a result of the decline in their water levels. Groundwater is the water resource for the region, and due to high agricultural and industrial demand, the Dibdiba aquifer is facing groundwater depletion. This study utilized climatic datasets projected under two scenarios obtained from CMIP6 and the Groundwater Modeling System (GMS). The objective was to evaluate the effect of projected climate change on the quantity of groundwater. Artificial recharge of treated wastewater from the wastewater treatment plant (WWTP) in Kerbala into groundwater aquifers has proven to be an effective method of mitigating groundwater depletion while providing a sustainable water supply. Eleven wells are distributed randomly within the research area; each of them is located within the unconfined aquifer. The groundwater levels in these wells were measured in situ from July 2023 to April 2024. The model was run for steady and unsteady flow conditions, and calibration at steady state was carried out using the groundwater head data for (7) wells. These seven wells were selected to represent the whole research region as well as shorten the simulation run duration in the calibration process. On the other hand, the transient calibration was performed employing measurements of groundwater heads for four wells. Calibration and validation results indicated convergence between the observed and simulated heads. The modeling findings showed that the increment in groundwater level is about 1.0, 1.85, and 2.25 m with artificial recharge of about 6000 m³/day, 9000 m³/day, and 12000 m³/day, respectively. The above findings illustrate the ability of artificial recharge as a highly promising strategy for addressing the water depletion and environmental issues in the Dibdiba aquifer. Doi: 10.28991/CEJ-SP2024-010-016 Full Text: PD
Fire Behavior of Concrete Beams Reinforced with Various Combinations of GFRP and Steel
No full textThis paper investigates the effects of key parameters on the fire resistance of concrete beams reinforced with various combinations of glass fiber-reinforced polymer (GFRP) and steel. The ratio of GFRP area (Af) to the total area (A) of GFRP and steel varied from 0 to 1, making steel, hybrid GFRP-steel, and GFRP-reinforced concrete (RC) beams. Finite element models of these beams were developed in SAFIR software and verified. The models were then used to analyze the effects of different key parameters on the fire behavior and fire resistance of these beams. The results demonstrated that the fire behavior of these beams was significantly affected by the Af/A ratio, load ratio, total reinforcement ratio, and concrete cover thickness, while it was marginally affected by steel and concrete strengths. The fire resistance decreased with the increases in load ratio and Af/A ratio, whereas it increased with the increases in concrete cover thickness or reinforcement ratio. Fire resistance slightly increased with the increase in the tensile strength of steel and slightly decreased with the increase in the compressive strength of concrete. The location arrangement of GFRP and steel bars in cross sections significantly affected the fire behavior and fire resistance of hybrid beams. The deflection rate limit, rather than the deflection limit, decisively governed the fire resistance of concrete beams reinforced with different Af/Aratios. Regression analyses yielded models for estimating the fire resistance. Doi: 10.28991/CEJ-2025-011-05-018 Full Text: PD
SEM-Based Decision Support Model for Cost-Quality Impact Analysis on a Fast-Track Project’s Duration
No full textThe fast-track technique was introduced to mitigate time overruns and meet project deadlines; however, limited understanding exists regarding how cost and quality-related decisions influence the duration of such projects. This study aims to analyze the impact of cost and quality variances on project duration, ultimately proposing a decision support model tailored for fast-track high-rise building projects. Data were collected from 159 respondents and analyzed using Structural Equation Modeling (SEM), through which four hypotheses were formulated. The findings reveal that both cost and quality variances significantly affect project duration, with quality variance also exerting a notable influence on project cost. Mediation analysis further demonstrated that cost variance serves as a statistically significant mediator between quality variation and project duration. The R² values of the proposed model indicate that 78.4% of the variation in project duration can be attributed to changes in cost and quality, while 72.9% of the variation in project cost is linked to quality changes. The Importance–Performance Map Analysis (IPMA) identified the early procurement of long-lead-time items, the adoption of a scope-freeze approach during the early design phase, and the over-design of facilities as the most critical and best-performing decisions. The model introduces novel β-values and confirms the statistically significant relationships among cost, quality, and time. Additionally, model validation metrics—including Q², RMSE, MAE, and CVPAT—demonstrated strong out-of-sample predictive power of the proposed framework