Current Issue : January-March Volume : 2026 Issue Number : 1 Articles : 5 Articles
Rail transport is widely regarded as an efficient and environmentally sustainable mode of mobility, although lifecycle emissions from infrastructure can diminish its ecological benefits. This study assesses a novel slab track system design that replaces conventional concrete components with recycled polymeric composite sleepers, supporting circular economy objectives. Analytical calculations (per EN 16432-2 and EN 13230-6) and finite element analysis (FEA) were conducted on a 2.6 m polymeric composite sleeper model under static vertical loading. The results demonstrate that bonded base layers comprising asphalt and hydraulically bound materials reduce bending stresses within the sleeper to 1.307 N/mm2, substantially below the 5.50 N/mm2 observed without bound layers and well below both characteristic fatigue limits. Laboratory validation via strain-gauge measurements corroborates the numerical model. Despite minor torsional effects from first-batch production, the polymeric composite sleeper design is structurally viable for slab track applications. The methodology is directly transferable to alternative composite designs, allowing material-based adaptation of mechanical performance. These findings support the use of recycled polymeric composite sleepers in slab track systems, combining structural adequacy with enhanced circularity. Further research can base itself on the findings and should incorporate long-term durability testing....
This paper presents a phase-based analysis of the spatial and architectural development of underground stations in the Warsaw Metro, focusing on 28 non-transfer stations constructed between 1983 and 2019. The research examines how design and functional solutions evolved over five construction phases in response to changing engineering methods, organizational frameworks, and urban contexts. A comparative analytical framework was developed, incorporating quantitative and qualitative parameters related to spatial layout, access schemes, and interior design features. The methodology combines archival documentation analysis, in situ field surveys, and typological classification. Findings reveal a clear trajectory from utilitarian, dual-purpose stations emphasizing structural durability and civil defense, toward more user-oriented designs prioritizing accessibility and intuitive navigation. Later phases show an expansion of multifunctional elements, including retail spaces, reflecting contemporary trends in metro station design. It contributes to a broader understanding of how adaptive design strategies enable metro infrastructure to respond to evolving urban needs and challenges, highlighting the importance of contextual integration for future metro developments....
Efficient production of high-quality cubical crushed stone is critical for road construction and concrete manufacturing. Conventional vibrating screens suffer from low cubicality and high energy consumption, limiting their applicability. We developed a novel spiral vibrating screen featuring a helical screening surface and adjustable oscillation parameters. Experimental studies were conducted on granite aggregates (5–20 mm) at vibration frequencies of 16–26 Hz and amplitudes of 1.5–4.0 mm to evaluate cubicality, screening efficiency, throughput, and energy consumption. Under optimal operating conditions (22 Hz, 3.0 mm amplitude), the prototype achieved 84–86% cubical particles, 93–95% screening efficiency, and specific energy consumption of 1.20 ± 0.05 kWh/t. Compared with conventional flat and drum screens, cubicality improved by 8–12 percentage points, while energy consumption decreased by up to 12%. The developed screen offers a scalable solution for producing high-quality cubical aggregates with lower energy demand and reduced clogging risks. These findings provide practical guidance for improving aggregate processing technologies....
The AA2124 aluminium alloy-based metal matrix composites (MMCs) reinforced with the silicon carbide (SiC) were examined under tensile creep at 300 ◦C. The tests were carried out for the materials of different SiC particle size (3 μm and 0.6 μm) and amount (17 vol.% and 25 vol.%). Creep curves under different constant stresses are presented. A high stress sensitivity of the composites tested was identified for a very narrow range of stress values. As a result, a threshold stress range separating the slow and fast creep stages was easily identified at around 5 Mpa for the composite with a larger SiC particle size and lower content and around 1 Mpa for the two other composites. It means that a very small change in stress applied to the structural element at elevated temperatures may lead to its very rapid collapse or even the destruction of the whole structure. The experimental programme was supplemented by the microstructural observations carried out using the scanning electron microscopy providing data necessary for better understanding the damage mechanisms of the material subjected to creep. An influence of voids on the mechanical response and fracture zones was identified. Attention was paid to the nature of degradation of the composites....
This study proposes a novel structural deflection measurement method using a single smartphone with an innovative scale factor (SF) calibration technique, eliminating reliance on laser rangefinders and industrial cameras. Conventional off-axis digital image correlation (DIC) techniques require laser rangefinders to measure discrete points for SF calculation, suffering from high hardware costs and sunlight-induced ranging failures. The proposed approach replaces physical ranging by deriving SF through geometric relationships of known structural dimensions (e.g., bridge length/width) within the measured plane. A key innovation lies in developing a versatile SF calibration framework adaptable to varying numbers of reference dimensions: a non-optimized calculation integrates smartphone gyroscope-measured 3D angles when only one dimension is available; a local optimization model with angular parameters enhances accuracy for 2–3 known dimensions; and a global optimization model employing spatial constraints achieves precise SF resolution with ≥4 reference dimensions. Indoor experiments demonstrated sub-0.05 m ranging accuracy and deflection errors below 0.30 mm. Field validations on Beijing Subway Line 13's bridge successfully captured dynamic load-induced deformations, confirming outdoor applicability. This smartphone-based method reduces costs compared to traditional setups while overcoming sunlight interference, establishing a hardware-adaptive solution for vision-based structural health monitoring....
Loading....