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2007 research outputs found
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Bearing Capacity and Strength of Bacterial Soil Columns Full-Scale Tests
No full textInfrastructure development often faces challenges due to soils with low bearing capacity, which can potentially cause instability and subsidence and threaten the safety of structures. Therefore, an efficient and environmentally friendly stabilization method is required. This study aims to evaluate the effectiveness of Microbial Induced Calcite Precipitation (MICP) in improving bearing capacity and soil strength through the formation of bacterial soil columns. This study employed a full-scale physical model test using 40 cm diameter and 200 cm deep soil columns filled with soil mixed with Bacillus subtilis, compacted, and cured for 56 days. The results showed significant improvements in the geotechnical characteristics of the soil, with CBR values increasing from 5.5% to over 12%, unconfined compressive strength reaching 345 kPa, and modulus of elasticity increasing to 12.5 MPa. Soil cohesion increased to 65 kPa, while internal friction angle increased from 10° to 34°. The novelty of this research is the application of MICP technology in the form of bacterial soil columns as an innovative, effective, and sustainable stabilization method to improve the mechanical properties of soft soils. Doi: 10.28991/CEJ-2025-011-04-06 Full Text: PD
Infrared Thermal Monitoring of Intersection Elements of Urban Road Infrastructure and Road Traffic Via Drone
No full textThis paper presents a thermographic analysis of a street junction within an urban road network, focusing on identifying thermal load sources generated by vehicle traffic”an increasingly significant environmental concern for urban populations. The study explores the application of thermographic methods at urban intersections and the creation of thermal maps. These approaches support the advancement of intelligent transport systems, aligning with smart city initiatives aimed at optimizing traffic flow management. Additionally, the findings provide potential for assessing the conditions of both road transport infrastructure and vehicles. By adopting this comprehensive perspective for monitoring urban environments and transportation systems, cities can enhance overall quality of life and public well-being. The results emphasize the value of conducting broad-scope studies, suggesting that combining ground-based and aerial thermal imaging leads to more informed decision-making. Doi: 10.28991/CEJ-2025-011-05-02 Full Text: PD
Evaluation of Strength Characteristics of Cement-Stabilized Rammed-Earth Material
No full textThe traditional method of rammed-earth construction is seeing a resurgence because of its minimal environmental impact and sustainability. Numerous elements, including soil composition, compaction procedure, stabilization methods, moisture content, and ambient conditions, affect the properties of rammed-earth materials. This research work aims to investigate the strength characteristics of cement-stabilized rammed-earth material. The strength characteristics involve compressive strength and splitting tensile strength. There are four soil types involved in the casting of cement-stabilized rammed-earth, i.e., 0C100S, 10C90S, 20C80S, and 30C70S. The moisture contents used are based on the OMC of Thar Desert sand, i.e., 11.5%, 12.5%, and 13.5%. While the cement contents used are, i.e., 5%, 10%, and 15%. The number of specimens cast is equal to 216. The results of compressive strength and splitting tensile strength tests conclude that strength increases with the increase in cement content; however, the increase in moisture content decreases the magnitude of compressive strength and splitting tensile strength. The increase in clay content up to 20% increases the compressive strength; a further increase in clay content, i.e., 30%, results in a reduction of compressive strength. The splitting tensile strength increases with the increase in clay content. The maximum compressive strength equal to 13.43 MPa is achieved in the specimen, i.e., 20C80S15c, with minimum moisture content used, i.e., OMC-1% (or 11.50%). While the maximum splitting tensile strength achieved is 6.68 MPa of the specimen, i.e., 30C70S15c, with a moisture content of 11.50%
Analysis of Influence Factor of Soil-Structure Interaction Considered in Pile Analysis using Finite Element Analysis
No full textThis study evaluates two often‑overlooked factors in pile analysis (passive earth pressure and the pile-soil contact method) and quantifies their combined influence on load–settlement response, shaft friction, and stress distribution. Conventional finite element analyses rarely consider both passive earth pressure and pile–soil slip simultaneously. This research quantifies the influence of these two factors on the load–settlement behavior, shaft friction, and stress transfer mechanisms of a single square pile. A laboratory model test was conducted using a 50 × 50 × 150 mm model pile embedded in loose sand with a relative density of 25%, and the same conditions were replicated using a 3D FEM model in ANSYS. The soil was modeled using the Mohr–Coulomb model, with parameters obtained from direct shear tests, and the pile was defined as a linear elastic material. The lateral boundaries were defined under two conditions: a general roller-type boundary and a new boundary condition incorporating depth-dependent passive earth pressure. Interface behavior was analyzed with both bonded and frictional contacts. The passive earth pressure boundary condition reduced post-yield settlement error from 22% to 6% and increased calculated shaft friction by 4%, resulting in a post-yield settlement curve that closely matched the experimental results. Bonded contact overestimated the bearing capacity by 17% and produced unrealistic stress concentrations, while Frictional contact accurately reproduced the observed slip surface and ultimate bearing capacity within a 3% margin of error. Parametric analysis revealed that the elastic modulus governed pre-yield stiffness, whereas the friction coefficient primarily influenced plastic deformation behavior. By combining the depth-dependent passive earth pressure boundary with experimentally calibrated frictional contact, this study successfully captured both lateral confinement effects and interface slip, which are typically analyzed separately. Consequently, the predictive accuracy for settlement and bearing capacity of friction piles in sandy soils was empirically improved
Experimental and Bearing Capacity Research on Prestressed Shape Memory Alloy Strips Confined Concrete Column
No full textThe prestressed shape memory alloy (SMA) strips confined columns are a novel reinforcement method, which not only exerts active confinement stress on the core concrete but also avoids the common stress hysteresis problem in reinforcement. This paper performed axial compression tests on eight sets of concrete columns with varying SMA strip width, net spacing, and pre-strain, and the impacts of these variables regarding the failure pattern, bearing capacity, and deformability of the specimens were investigated. A calculation model for the bearing capacity of SMA strips actively confined to concrete columns was established and contrasted with the prediction performance of the BP neural network. The results indicate that compared to the unconfined column, SMA strip-confined columns exhibit obvious ductile failure under compression, with the highest increase of bearing capacity and deformability reaching up to 20.27% and 24.96%, respectively. The confinement effect becomes better and better with the increasing strip width or the decreasing strip net spacing. When the strip pre-strain gradually increases, the bearing capacity of confined columns gradually improves, while the deformability first enhances and then weakens. The experimental data of other scholars is used to verify that the calculation results accord with the experimental results well, and the prediction precision of the proposed calculation model exceeds that of the BP neural network. Meanwhile, it is confirmed that the BP neural network exhibits a high fitting level in bearing capacity prediction (R2training=0.990 and R2test=0.965), offering a novel approach for predicting the bearing capacity of structures
Simplified and Rapid Modeling of Road Embankments Slope Safety Factor Using Regularized Regression Techniques
No full textThe primary objective of this research is to examine the viability of simplified regularized regression models in predicting the slope safety factor of road embankments. The methodology involves developing and comparing several regularized linear regressions against conventional methods. A total of 276 data points are collected from the literature, and 70% of these are utilized for model training, while 30% are employed for testing. The findings indicate that these models yield results better than established approaches, with Stochastic Gradient Descent and Bayesian Ridge achieving strong performances. This study provides an alternative technique that offers rapid and manually solvable equations, thus enhancing practical adaptability for routine professional tasks. The novelty lies in bridging the gap between traditional finite element-based investigations and emerging data-driven methods, demonstrating that regularized regression can be both simple and sufficiently accurate. Overall, the study outcomes emphasize the significance of these advanced yet computationally light models for road embankment stability assessments, presenting a valuable and time-efficient tool for practitioners
Influence of Blast Furnace Slag on Concrete: Mechanical Strength and Microstructural Characterization
No full textThis study aims to quantitatively assess the effect of granulated blast furnace slag (GGBFS) as a partial replacement for Portland cement on the mechanical and microstructural performance of concrete with a design compressive strength of 280 kg/cm². A comprehensive experimental program was conducted to evaluate compressive strength, indirect tensile strength, flexural strength, and modulus of elasticity at curing ages of 7, 14, and 28 days, in accordance with ASTM standards. Microstructural characterization included Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy with Energy-Dispersive X-ray Spectroscopy (SEM/EDS), and X-ray Diffraction (XRD). The results demonstrated that incorporating GGBFS, particularly at 16% and 20% replacement levels, led to significant improvements in compressive strength and stiffness at 28 days, while early-age tensile strength reductions were mitigated over time due to the latent pozzolanic activity of the slag. Microstructural analyses revealed a denser cementitious matrix, enhanced chemical stability, and the formation of new crystalline phases. Statistical analyses (ANOVA and Kruskal–Wallis) confirmed significant effects on flexural strength and elastic modulus. These findings underscore the potential of GGBFS to improve concrete performance and promote sustainability by valorizing industrial by-products and reducing CO₂ emissions. This work provides a robust experimental and analytical basis for optimizing GGBFS incorporation in durable, performance-enhanced concretes
Optimal Placement of Vibration Control Systems in a Smart Civil Engineering Structure
No full textAdvancements in construction technologies have led to the development of lighter and more flexible structures, which pose new challenges in terms of seismic resistance. This study explores the effectiveness of integrating an Active Tendon (AT) control system to mitigate seismic-induced vibrations in tall buildings. The main objective is to identify the optimal placement of these active control devices to maximize structural performance. To this end, three optimization approaches are investigated: modal controllability analysis, controllability index evaluation, and genetic algorithm (GA)-based optimization. The methodological approach is based on the development of a comprehensive flowchart that integrates the optimization procedures alongside a comparative assessment of passive and active control strategies. Detailed simulations were carried out in MATLAB, enabling accurate time-history analyses and the implementation of customized control algorithms. This framework enables extensive parametric studies and supports a rigorous assessment of control system performance. The results clearly show that optimal tendon placement leads to a substantial improvement in vibration mitigation compared to uncontrolled cases. Comparative analyses underscore the respective strengths and applicability domains of each optimization method, confirming their effectiveness in identifying optimal actuator locations. The novelty of this study lies in the integration of modal and evolutionary optimization techniques within a unified framework, offering a systematic and versatile approach to the placement of control systems in civil engineering structures. The practical recommendations derived from this study provide valuable guidance for engineers and designers seeking to improve structural performance under seismic loading
Subsurface Mapping and Geotechnical Design for Landslide Mitigation
No full textThe landslide near the PT Molindo Incinerator Unit poses a significant threat to the facility’s structural integrity. Without immediate mitigation measures, the incinerator building is at risk of collapse, potentially impacting adjacent settlements due to cascading structural failures. To reduce the risk of further instability, urgent geophysical investigation is required to characterize the subsurface lithology and assess the groundwater table conditions. A geoelectrical resistivity survey was conducted using the Schlumberger configuration across 8 measurement points along a 100-meter survey line, with 10-meter electrode spacing. The resistivity measurements ranged from 3.30 to 25 Ωm, which were interpreted as clay-rich layers; 26 to 167 Ωm, corresponding to sandy clay; and 167 to 15,944 Ωm, indicating bedrock. The potential slip zone is interpreted at an average depth of 20 to 25 meters, indicated by very low resistivity values with resistivity values between 3.30 and 25 Ωm. Field observations confirmed that the landslide materials predominantly consisted of clay soils, distributed within two distinct layers beneath the incinerator unit. The combined depth of the clay and overlying sandy layers was estimated to reach approximately 20-25 meters from the ground surface. To ensure the effectiveness of structural mitigation, a retaining wall must be designed to extend beyond this depth threshold. Numerical simulations using Slope/W software indicated that soil nailing techniques yielded safety factors ranging from 1.32 to 1.81 under static conditions and 1.22 to 1.43 under dynamic conditions. Predicted deformations ranged from 0.01 to 0.02 meters (static) and 0.02 to 0.03 meters (dynamic). These results suggest that soil nailing is a viable reinforcement method to stabilize slope movements, particularly during periods of high rainfall. Additional recommended mitigation strategies include the installation of surface and subsurface drainage systems to control water flow, constructing retaining structures to serve as physical barriers to soil movement, and using vegetative cover to enhance slope stability
BIM-Based Integrated Model for Project Cost Estimation: A Case Study for Concrete Elements
No full textConstruction projects often struggle to align design models, cost estimates, and scheduling processes. To address this challenge, this study presents an integrated 5D BIM model that automates cost and schedule estimation by linking 3D BIM components to a structured database of historical productivity and activity data. A unique coding system connects each BIM object to its corresponding construction tasks, enabling automatic generation of resource-loaded schedules with associated durations, costs, and crews based on the selected construction method. The workflow integrates Autodesk Revit, Navisworks, a relational (SQL) database, and Primavera P6 to achieve seamless interoperability across design, estimating, and scheduling tools. The model is validated through a case study of a six-story reinforced concrete building. Findings show that the approach significantly improves estimation, accuracy, and efficiency. Predicted costs closely match actual values, thereby reducing dispersion among estimates. The automated process minimizes manual data handling while keeping cost and schedule outputs synchronized. Novel contributions include the incorporation of detailed historical productivity data, construction method alternatives, and structured cost/activity records into a unified framework, representing a methodological advance in 5D BIM that bridges the design, estimating, and scheduling domains for more reliable and automated project planning