2031 research outputs found
Sort by
Flexural Behaviour of Prestressed Post-Tension Voided Biaxial Slab Under Uniformly Distributed Load
Full text linkThis study examines the flexural behavior of prestressed post-tensioned voided biaxial slabs under uniformly distributed loads (UDL) to evaluate structural performance, quantify material efficiency, and validate finite element models. Four full-scale slabs”solid and voided, with and without post-tensioning (PT)”were experimentally tested under UDL using a multi-level steel beam system to simulate uniform loading. Parameters such as crack initiation, deflection, and failure modes were monitored. Nonlinear finite element analysis (FEA) in ANSYS, employing Solid65 and Link180 elements, replicated material behavior and boundary conditions. The results showed that PT-voided slabs retained 96% of PT-solid yield capacity while reducing concrete volume by 22%, achieving a 21% self-weight reduction. Post-tensioning enhanced stiffness by 21% compared to non-PT voided slabs and delayed crack initiation. FEA predictions closely matched experimental data, with ≤10% deviation in load-deflection responses and consistent crack patterns. The novelty lies in demonstrating that PT effectively mitigates stiffness reductions (6% vs. PT-solid) caused by cuboidal voids, enabling high-performance, lightweight designs. This integration of PT with voided systems offers a sustainable solution, reducing material usage by up to 22% while maintaining structural integrity, thereby advancing eco-efficient construction practices. Findings provide critical insights for optimizing voided slab applications in modern infrastructure. Doi: 10.28991/CEJ-2025-011-05-09 Full Text: PD
Assessment of Organic Carbon Stocks at Landscape Levels Using the InVEST Software
Full text linkThis study aims to calculate and assess organic carbon levels at various landscape levels of the Crimean Peninsula using the Carbon Storage and Sequestration model of the InVEST software. It outlines the stages of working with this model and highlights limitations such as the quality of input data, temporal coverage, and spatial resolution, which can significantly influence the results. Assessment of organic carbon stocks in soils, aboveground and belowground biomass, and vegetation types revealed that the highest carbon concentration was in the low-altitude landscape level of the southern macroslope. From 2017 to 2023, an annual decrease in organic carbon stocks of 0.062 t/ha was recorded, which is likely linked to climate change and shifts in land use. This research provides the first calculations of organic carbon content within the landscape levels of the Crimean Peninsula. As carbon is a significant greenhouse gas, its accumulation or emissions directly affect climate change. Evaluating organic carbon stocks in ecosystems enhances our understanding of their role in mitigating climate change and informing carbon dioxide (CO2) reduction strategies. These findings highlight the need to consider vegetation types and their changes when calculating organic carbon in landscapes and supporting regional environmental policy development. Doi: 10.28991/CEJ-2025-011-03-018 Full Text: PD
An Innovative Design of Strip and Circular Footings on Sand Surface: Stress–Density Framework
Full text linkThe bearing capacity of shallow foundations subjected to vertical centric loads has been extensively investigated. Despite the variability in the bearing capacity factor Nγ as proposed by different methodologies, the classical solution remains dominant in design codes. Critical variables affecting the bearing capacity of sand encompass sand particle morphology, footing width or diameter (B or D), mean effective stress level (p'), and sand relative density (Dr). Different sand types may exhibit distinct mobilization friction angles (ϕm) at the same Dr and p', resulting in varied stress-strain behaviors. Thus, the actual bearing capacity may not be accurately reflected by estimates of Ngamma derived from a constant peak friction angle (ϕp) value. In this study, a Three-Dimensional Finite Element Model (3D-FEM) has been applied to both strip and circular footings, employing a hypoplastic constitutive sand model to replicate sand behavior. The model efficiently replicates the compression and shear behavior of sand across a wide range of confining pressures and densities. A comprehensive parametric analysis has been conducted, encompassing a broad range of parameter variations. The principal objective is to present an innovative design approach concerning the bearing capacity of footings for diverse sand characteristics across an extensive array of sand properties. Additionally, a correlation has been established between the bearing capacity factors for strip and circular footings.
Doi: 10.28991/CEJ-2025-011-03-03
Full Text: PD
Stress Concentration Factors in Tubular T-Joint Braces Under Compressive Loads Using Artificial Neural Networks
Full text linkStress concentration factors (SCFs) are often calculated using formulas based on experimental testing and finite element analysis (FEA). While maximum SCF could occur at any location along the brace axis of the tubular T-joint’s brace, only the SCFs at the crown and saddle points can be determined from the available formulae, which can result in imprecise fatigue life determination. The current study presents a methodology to determine the SCFs in T-joints using FEA and ANN. ANNs are more effective than conventional data-fitting techniques at modelling intricate phenomena. In this work, parametric equations to estimate the SCFs of the T-joint’s brace under compressive loading were developed. Utilizing parametric equations allows for rapid estimates of SCFs, in contrast to time-consuming FEA and expensive testing. The equations are based on an artificial neural network’s training weights and biases (ANN). 625 finite element simulations were performed on tubular T-joints with various dimensions under compressive loads to determine the SCFs at the brace of the T-joint. These SCFs were then used to train an ANN. The weights and biases of the ANN were subsequently used to derive equations for calculating SCFs based on dimensionless parameters. The equations can estimate the SCF of a T-joint brace with less than 7% error and a root mean square error (RMSE) of less than 0.19
Analyzing and Modeling Toll Road Service Performance: TRSQ Model and Emerging Influencing Variables
No full textThe construction of toll roads supports economic and social mobility while driving regional development. However, toll road services face challenges such as deteriorating road quality, lack of facilities, and traffic disruptions due to accidents or repairs. This study aims to identify variables, examine their relationships, and develop a model for the factors influencing toll road services. The research uses both quantitative and qualitative approaches with explanatory research. The initial model of variables refers to the TRSQ model, which includes information, accessibility, reliability, mobility, safety and security, rest areas, and responsiveness. A questionnaire instrument is used and tested with SPSS for data validity and reliability. The data is then processed with SmartPLS to examine the relationships between variables. The results show a positive and significant impact on toll road service performance. However, 36.9% of toll road service performance is influenced by factors outside the model. To identify additional variables, bibliometric analysis using VOSviewer and expert opinions was used. The findings revealed that environmental factors, innovation, climate change, and public-private partnerships also affect toll road service performance. This led to the development of a model that serves as a framework for improving toll road service quality
Factors Affecting Properties of Cellular Lightweight Clay Improved with Fly Ash Geopolymer and Cement
Full text linkThis research investigated the unit weight and unconfined compressive strength (UCS) of cellular lightweight high-calcium fly ash geopolymer and cement-stabilized soft Bangkok clay (CLFAG-OPC stabilized SC) as potential lightweight embankments and backfill materials. The investigated parameters included the soft clay:fly ash (SC:FA) ratio (50:50 to 90:10), ordinary Portland cement (OPC) content (0%-3%), water content (1.5LL-3.0LL), liquid alkaline content (L) (0.6FA to 1.5FA), NS:NH ratio (0.5-3), NH concentration (8 M), air foam content (Ac) (0%-150% by SC volume), and curing time (7-90 days). The results indicated that the SC:FA ratio, OPC content, water content, NS:NH ratio, L content, and Ac significantly influenced both the unit weight and UCS of samples. Increasing water content, L content, and Ac generally reduced unit weight, except when influenced by FA content, OPC content, and the NS:NH ratio. The optimal composition for maximum UCS was achieved with an SC:FA ratio of 50:50, OPC content of 3%, water content of 2.0LL, NS:NH ratio of 1, L content of 0.6FA, and 0% Ac. A predictive equation for unit weight was proposed using phase diagrams. Additionally, mix design charts were shown to be valuable tools for calculating the unit weight and UCS, demonstrating their effectiveness for lightweight embankment and backfill applications
Advancing Seismic Performance: Experimental Behavior of Hybridized Steel-FRP Composite Bars
No full textThis study investigates the structural performance of reinforced concrete (RC) columns reinforced with hybrid Steel-FRP Composite Bars (SFCBs), offering a sustainable alternative to conventional steel and fiber-reinforced polymer (FRP) reinforcement. Eight large-scale RC columns, measuring 400 × 400 mm in cross-section and 1850 mm in height, were tested under combined cyclic and axial loading to simulate seismic conditions. The experimental variables included SFCB diameters (14 mm, 18 mm, 22 mm), axial load ratios (20%, 30%, 40%), and stirrup spacing (80 mm, 100 mm, 150 mm). The results indicate that SFCBs can effectively replace traditional steel reinforcement, providing comparable load-bearing capacity while significantly improving durability. Columns reinforced with SFCBs demonstrated superior initial stiffness and achieved higher drift ratios than steel-reinforced columns, exceeding the limits set by international design codes (ACI 440.2R, CSA S806-12, Eurocode 8) with maximum drift ratios of up to 6.5%. Increasing the SFCB diameter from 14 mm to 22 mm enhanced peak load capacity by 14%–20% and improved drift ratios by up to 113%. However, higher axial load ratios and wider stirrup spacing were found to reduce ductility. Specifically, increasing the axial load ratio from 20% to 40% decreased ductility by 13.46%, while increasing stirrup spacing from 80 mm to 150 mm reduced ductility by 8.90%. These findings underscore the potential of SFCBs to enhance the performance of RC columns in seismic and corrosive environments, offering a durable and sustainable solution for modern infrastructure. To the authors' knowledge, this study represents the first comprehensive investigation into the behavior of SFCB-reinforced RC columns under combined cyclic and axial loading, providing valuable insights for the design of resilient concrete structures
Influence of Emulsion Type and Moisture on the Stiffness of Stabilized Granular Soil
Full text linkThe objective of this study is to investigate how moisture content affects the stiffness of a gravelly-sandy soil stabilized with asphalt emulsion, considering different types of emulsion (medium- and slow-setting) and modified compaction energy. Dynamic triaxial tests were carried out to determine the stiffness of specimens at different moisture contents, considering the dry and wet branches of the compaction curve, all stabilized with 2% asphalt emulsion. The influence of moisture content and emulsion type was assessed using robust analysis of variance (ANOVA), allowing the evaluation of statistical significance and the interaction between factors. The results showed that the stiffness of the stabilized soil is strongly influenced by moisture content, with a peak value observed near the optimum moisture (~8.2%). The slow-setting (SS) emulsion achieved the best performance, reaching 938.94 MPa, representing a 452.32% increase compared to the untreated soil. The medium-setting (MS) emulsion also produced a significant stiffness gain (375.29%). Statistical analysis indicated that emulsion type was the most influential factor (Q = 1747; p = 0.001). This study contributes to the literature by experimentally and statistically demonstrating how moisture content and emulsion type affect the stiffness of stabilized soils
LiDAR-Based Pothole Patching Quantity Estimation and Cost Saving Analysis Using Segmented TIN Model
Full text linkPotholes represent a significant form of road distress, and the conventional method for estimating the required repair material typically assumes a cuboidal shape for each pothole. This approximation often leads to an overestimation of pothole volume, resulting in excessive patching material and increased costs. To address this limitation, the present study introduces a LiDAR-based segmentation and digitization method. This approach utilizes only the point cloud data of potholes obtained via terrestrial laser scanning to generate accurate 3D surfaces, contours, and a Triangulated Irregular Network (TIN), thereby enabling precise volume and patching quantity calculations. The findings revealed that the volume and patching quantity estimated using the traditional cuboidal method are two to four times greater than those calculated through the proposed LiDAR-based approach. This clearly demonstrates that the conventional method leads to unnecessary procurement of patching materials. Cost analysis further indicated that the LiDAR-based approach could result in savings of approximately INR 3,500 per pothole in India, $262 in the USA, and £150 in the UK. Given that millions of potholes are repaired annually in each country, adopting the proposed LiDAR-based method has the potential to yield substantial cost savings on a national scale
Evaluation of Using Slag Powder as a Filler for Asphalt Concrete
No full textFiller materials have a significant effect on the performance of asphalt concrete by filling the voids and modifying the binder viscosity. Many types of filler have been used; the Ordinary Portland Cement (OPC) is the most used due to its properties, which align with the required properties. The cost, production emissions, and drain for natural resources formed negative points of its usage. Accordingly, this study is dedicated to evaluating the asphalt concrete properties using byproduct material as a mineral filler. The Electric Arc Furnace Slag Powder (EAFSP) has been selected to replace the OPC with ratios from zero to 100% with an increment of 25%. Marshall and Indirect Tensile Strength (ITS) results in different testing conditions were employed to evaluate the use of EAFSP. The results revealed that using EAFSP as a filler material improved asphalt concrete strength and resistance to moisture effects, especially at high temperatures. More binder content was needed, about 0.6%, the voids in the total mix were reduced by about 1%, and the stiffness increased by about 0.5 kn/mm when replacing the OPC with EAFSP. Based on that, it's recommended that the replacement ratio should be proposed according to the weather condition, materials availability, and cost-benefit analysis