Journal of Civil Engineering Beyond Limits (CEBEL)

Selenay Gençcelep Volkan Kahya Kemal Hacıefendioğlu

This study presents a comparative performance assessment of four vision-based motion extraction approaches—Lucas–Kanade, Farnebäck, Horn–Schunck, and a phase-based method—for vibration identification and modal parameter estimation in a laboratory-scale single-story reinforced concrete (RC) frame subjected to controlled impact excitation. High-speed video recordings (216 fps) are processed through a custom-developed graphical user interface that standardizes region-of-interest (ROI) selection, pixel-to-length calibration, displacement extraction, and data export, enabling a fair algorithm-to-algorithm comparison under identical experimental conditions. Displacement time histories obtained from each method are evaluated in both the frequency domain using the Fast Fourier Transform (FFT) and in the modal domain via Operational Modal Analysis (OMA) implemented in the PyOMA_GUI environment. The comparison focuses on the low-amplitude vibration regime, where optical-flow robustness and noise sensitivity become critical. The results indicate that Lucas–Kanade and Farnebäck consistently identify the first natural frequency with strong repeatability across ROIs and yield modal stabilization patterns that agree well with OMA-based estimates. Horn–Schunck provides acceptable identification within the expected frequency band; however, its global smoothness constraint tends to attenuate true motion content and may introduce frequency shifts under low-amplitude responses. In contrast, the phase-based approach does not recover reliable modal parameters in the investigated configuration, exhibiting dominant components around 50 Hz rather than the structural mode near 26 Hz, suggesting susceptibility to experimental noise sources and insufficient motion content. Overall, the findings provide practical guidance for selecting optical-flow-based algorithms for vision-based structural identification and support their use as complementary tools in structural health monitoring applications.

https://doi.org/10.36937/cebel.2026.11112

Dina Bekenova Abdussamet Arslan

Concrete dams are massive hydraulic structures whose long-term safety depends on durability, thermal behavior, and time-dependent material properties rather than initial strength alone. Throughout their service life, dam concrete is subjected to combined mechanical, thermal, hydraulic, and chemical actions, which may lead to progressive degradation if not properly controlled. This study examines the assessment and monitoring of concrete properties in dam construction from a life-cycle perspective. Key groups of concrete properties, including mechanical, physico-transport, thermal, and durability-related characteristics, are discussed in relation to degradation mechanisms. International quality control and monitoring practices are reviewed and compared with current approaches applied in Turkey. The results highlight the importance of integrated laboratory testing, construction-stage control, and long-term monitoring systems for improving predictability, early damage detection, and service life management of concrete dams.

https://doi.org/10.36937/cebel.2026.11113

Zafer Kurt Batuhan Hacımustafaoğlu Talip Çakmak İlker Ustabaş

Humanity's social and cultural expectations have shifted from producer to consumer in today's world, and consumption behaviors have changed significantly compared to the past. The storage of industrial waste by-products resulting from human economic activities has emerged as a significant problem. The revaluation of by-products after industrial activities provides important benefits in terms of the circular economy. In this study, the feasibility of using fly ash, waste glass, and burnt coal waste as pozzolanic materials in alkali-activated mortars was investigated. In the study, a 12-molar (12M) NaOH solution was utilized as the alkali activator. The alkali activator-to-binder ratio was maintained at a constant 0.45 for all mixtures. After the mortar was produced, it was exposed to a curing temperature of 90°C for 72 hours. The data obtained from the mechanical tests showed that the highest compressive strength was achieved in the BCR20WG80FA0 sample at 25.99 MPa, while the highest flexural strength was obtained in the BCR20WG80FA0 sample at 5.15 MPa. The mechanical strengths obtained with the materials used show that the performance of waste glass and burnt coal waste is higher than that of fly ash. The findings suggest that these materials are viable candidates for enhancing environmental sustainability in construction.

https://doi.org/10.36937/cebel.2026.11115

Elif Agcakoca Zeynep Yaman Sebghatullah Jueyendah1 Joseph Doucke Kahudi Omende

This study presents a comparative evaluation of Eurocode 3 (EN 1993-1-1) and ANSI/AISC 360 regarding design requirements for steel elements subjected to axial load and combined axial-bending compression. Especially for thin-walled rectangular section elements, the transition from Class 3 to Class 4 in Eurocode 3 completely alters the design outcome and even reverses the regulatory framework for Eurocode 3 and AISC section sizing. The behavior of steel elements is examined from theoretical, analytical, and code-based perspectives, considering section classification as well as local buckling, global instability, and lateral-torsional buckling conditions. For flexural behavior and LTB (lateral–torsional buckling), open I-sections are considered. Closed RHS members are assessed only under axial compression for stability-critical behavior. For the representative thin steel column (KL/r = 128), Eurocode 3 predicts a design buckling resistance slightly higher than AISC 360 when the section is treated as Class 3 (0.61 MN vs. 0.59 MN); however, when Class 4 behavior is correctly accounted for through the effective section approach, the Eurocode 3 resistance drops to 0.19 MN, highlighting that cross-section classification can be as influential as the chosen design standard for stability-critical members.

https://doi.org/10.36937/cebel.2026.11117

Ahmet Atalay Sedat Öksüz

In this study, B 70/100 penetration grade bitumen obtained from Batman Refinery was modified using styrene-butadiene-styrene (SBS) polymer (3–5%) and warm mix asphalt (WMA) additives (1–3%) to evaluate the changes in physical properties and temperature sensitivity under cold climate conditions. The modified binders were characterized by penetration, softening point, and flash point tests; and the penetration index (PI) was calculated to represent temperature sensitivity. A 3×3 factorial experimental design was applied in the study; the effects of SBS and WMA additives were analyzed using a two-factor ANOVA method based on variance decomposition. The findings show that the variation in binder properties is largely controlled by the WMA dosage, while SBS provides a secondary but significant contribution. In order to develop a multi-criteria evaluation approach; Softening point, penetration index, flash point, and penetration parameters were combined into a single performance indicator using an objective weighting method, creating the criteria importance through intercriteria correlation (CRITIC)-based Binder Performance Index (BPICRITIC ). Analysis results revealed that flash point had the highest independent information content among the evaluated parameters. According to performance ranking, the combination of 5% SBS and 1% WMA provided the most balanced performance in terms of hardness, temperature sensitivity, and processability criteria. Conversely, higher WMA content, especially at lower polymer ratios, was found to reduce the positive effects of SBS. It should be noted that, since each experimental combination is represented by a single measurement, the findings should be evaluated at a comparative laboratory scale for unaged binders. In conclusion, the proposed BPICRITIC approach offers a practical and systematic decision support tool that can be used in pre-binder optimization for coating systems to be applied in cold climates.

https://doi.org/10.36937/cebel.2026.11127