Abstract The structural damage observed in buildings highlights the crucial need for improved design quality in seismic-resistant construction systems, particularly for steel structures. This necessitates the development of earthquake-resistant structural systems that perform effectively both technically and architecturally. This study investigates the seismic behaviour of long links in Eccentrically Braced Frames (EBFs) strengthened using a hybrid method that combines flange thickening steel plate, and diagonal stiffeners. Five specimens were constructed and tested under cyclic lateral loading according to AISC-341-16 protocols. The specimens include one control link and four variations of flange and web strengthening, which were modified based on previous research. The research aims to propose novel strengthening methods that correlate the seismic performance of conventional structures with variations of the effective long link. Test specimens and experimental setups were designed considering boundary conditions and structural laboratory limitations. Results indicate that the specimens that were strengthened at both ends and mid-span with flange thickening and diagonal stiffeners attained the peak structural load capacity (27.48% increase) and stiffness (28.47% increase). However, its energy dissipation capacity was compromised by the implementation of stiffeners, which constrained plastic zone development. The specimen with only flange thickening demonstrated the highest ductility (1.54) and best energy efficiency (38.90%). Experimental results confirm that the hybrid strengthening technique effectively enhances cyclic performance in long-link EBFs, addressing both strength and ductility requirements in seismic-resistant structures.

Abstract The article focuses on a comprehensive analysis of prestressed road bridges in the administration of the Technical Administration of Communications of the Capital City of Prague. Prague (TSK) in the Czech Republic. Most of the structures were mainly built between the 1960s and 1980s, mainly various types of prefabricated structures. The project evaluated the diagnostic surveys and load capacity calculations carried out so far on several dozen constructions. Detailed diagnostic surveys, which are carried out according to methodological standards and include visual inspections, laboratory and chemical analyses of the concrete, carbonation measurements, chloride concentration determinations, as well as direct inspection of the condition of the prestressing reinforcement, including endoscopy of the tendon ducts, play an essential role in the evaluation process. The paper summarizes and statistically evaluates the findings obtained from the analysis of superstructure made of I-73 Girders and gives an overall view of the condition of these bridges, with emphasis on the estimation of the residual service life and possible rehabilitation measures to increase their reliability and extend their service life.

Abstract The article presents the results of experimental and numerical analyses of the behaviour of steel bridge sleepers on the steel railway bridge with member deck at km 5.230 of the A2 track in the Žilina – Teplička, marshalling yard section. The results of in-situ measurements during static and dynamic proof-load tests are presented, which are confronted with the outputs of numerical analyses using a computational model of the bridge superstructure created in the SCIA Engineer software. The stringers of the member deck directly supporting the sleepers were also investigated. Experimental analysis revealed significantly higher dynamic effects of the traffic test load on the stringers compared to the expected theoretical dynamic effects given by the standard regulations. On the contrary, in the case of steel sleepers, the experimentally determined dynamic effects of the traffic test load were very low. The results of the analyses pointed out the need to pay increased attention to the correct seating of the steel sleepers on the support strip to avoid unfavourable effects due to eccentric support of the sleepers. Another recommendation for the using steel sleepers presented in conclusion is to pay increased attention to the bridge deck members during regular inspections regarding the possible occurrence of fatigue damage due to their higher dynamic response on actual traffic load.

Abstract This study explores the experimental work for six Specimens used to study the strengthening effect of ultra-high-performance concrete, validation and evaluation of numerical analysis methodology of ultra-high-performance concrete (UHPC) beams through the application of carbon fiber-reinforced polymer (CFRP) strips in various reinforcement configurations. The experimental program evaluated several CFRP arrangements, including full-face wrapping, U-shaped and side-bond, and strips applied at different angles, spacings, and thicknesses. These configurations were assessed to understand their influence on the beams’ shear resistance and failure modes. The control beam, unstrengthened with CFRP, experienced a typical shear failure. In contrast, the use of CFRP strips, particularly when applied at inclined angles, significantly improved the beams’ load-bearing capacity and altered the failure behaviour. Inclined strips proved more effective than perpendicular ones, and their performance closely approached that of fully wrapped configurations. Wrapping the entire effective area or using wider strips not only enhanced the shear strength but also shifted the failure mode from shear-dominated to flexure dominated in most cases. Notably, the most comprehensive reinforcement method, complete encapsulation of the beam, resulted in the highest structural improvement, although it also led to a return to a shear dominant failure mode. These results highlight the importance of reinforcement configuration and orientation in optimizing the structural performance of UHPC beams using CFRP materials.

Abstract The hydraulic analysis of potable water is essential for acquiring an accurate understanding of the network’s operation and its associated issues, as well as for employing a scientific approach to its potential expansion, given the continuous rise in population density and urban development. The aim of the present study is to evaluate the operational performance of the water distribution network in the Muhandisin Al-Nidal neighborhood in Karbala City. The study utilized CAD Earth, Google Earth Pro, and WaterGEMS CONNECT Edition version 2 to construct a hydraulic model for simulating the behavior of the pipe network. The measurements of water flow at the source nodes were conducted using a wall-mounted ultrasonic flow meter (Eurosonic 2000). The model was calibrated at 17 connection points, encompassing pressures and flow. Pressure readings were acquired at designated points utilizing Bourdon gauges. study was examined as a steady-state analysis and during the peak period of daily consumption to assess the outcomes. The results indicated a significant reduction in pressure within the network pipes with a correlation coefficient of 0.95 and pressures ranging from 1.63 psi (1.15 m H₂O) to 9.36 psi (6.58 m H₂O). The flow velocities in the internal distribution system and major pipes ranged from 0.0001 to 0.546 m/s, indicating suboptimal hydraulic performance of the network.

Abstract Bar soil (locally known as “terre de barre”, a ferralitic soil common in southern Benin), a ferralitic material abundantly available in southern Benin, offers a low-cost local resource but exhibits poor geotechnical performance, particularly low bearing capacity and high sensitivity to water, making it unsuitable for road construction. This study investigates the stabilization of bar soil through the incorporation of pulverized ceramic waste (broken tiles), ground and sieved to 0.08 mm, in proportions ranging from 2.5% to 15% by weight. Geotechnical characterization tests were conducted in accordance with current ISO and French standards. The results demonstrate a significant improvement in the treated soil’s properties. While the untreated bar soil contains 48% fines and fails to meet the Experimental and Study Center for Building and Public Works (CEBTP) specification limits, the addition of 7.5% ceramic waste reduces fines to 28%, enhancing the particle size distribution. Furthermore, the plasticity index decreases to 13 at 12.5% ceramic content, and the maximum dry density reaches 2.10 t/m³ at 15%, exceeding the minimum threshold of 1.90 t/m³. The California Bearing Ratio (CBR), a key indicator of load-bearing capacity, increases from 23% for raw soil to 48% at 15% ceramic waste, qualifying the material for use in sub-base layers under traffic classes T1 to T5. Based on these findings, an optimal ceramic waste content between 7.5% and 15% is recommended. This approach offers a technically effective and economically viable solution aligned with CEBTP design guidelines 1984, revised in 2019.

Abstract Stone matrix asphalt (SMA), a gap-graded asphalt mix characterised by excellent durability, rutting resistance, and stone-on-stone contact, requires a strong stabilising agent to prevent binder drainage. Waste jute fibre (WJF) enhances the sustainable performance of SMA pavements. WJF, a biodegradable and renewable natural fibre, stabilizes asphalt mixtures and enhances mechanical properties while lowering environmental effects. WJF enhances SMA’s tensile strength, promotes recycling, and reduces waste, carbon, and synthetic fibre use. WJF was added in 5 mm, 10 mm, and 15 mm lengths at 0.1%, 0.3%, 0.5%, and 0.7% by weight of the mixture. This study examined the volumetric, mechanical, and design methods of WJF-reinforced SMA mix using the Marshall test, drain-down, indirect tensile strength, and compressive strength. Optimum asphalt content, air voids, VMA, and Marshall stability were improved. Fibre-containing SMA mixtures have lower bulk-specific gravity. Marshall’s stability rises and declines with fibre content. The test findings show that 0.5% WJF at 10 mm improved stability by 19.09%, ITS by 19.24%, and compressive strength by 21.36%.

Abstract Concrete compressive strength serves as a critical quality control metric in construction engineering. Traditional empirical formulas and regression models struggle to capture multifactorial nonlinear relationships, while neural networks often exhibit hyperparameter sensitivity and overfitting issues. This study develops a Bayesian-optimized fully connected neural network (BOFCNN) that employs Gaussian process surrogate modeling to dynamically identify optimal hyperparameters (e.g., learning rate, neuron count), enhancing generalization capability. Utilizing 1,015 experimental datasets from the UCI repository, feature selection integrated Pearson-Spearman correlation with random forest importance ranking. The optimized model achieved state-of-the-art performance: MSE = 21.0745 MPa2, R² = 0.9080, MAE = 3.5028 MPa. Within the primary strength range (10–60 MPa), predictions showed strong agreement with experimental data, confirming the efficacy of Bayesian optimization in enhancing predictive accuracy. This establishes a robust computational framework for concrete strength prediction, enabling sustainable mix design optimization.

Abstract An experimental study was performed on reinforced concrete (RC) beams enhanced in flexural capacity using the Near Surface Mounted Fiber Reinforced Polymers (NSM-FRPs) method. This study evaluated the efficacy of various FRP application processes and provided quantitative data on the bonding behavior between FRP and concrete. Effects of FRP type and shape, with equivalent area, on load-bearing capacity, midspan deflection, and failure mode of RC rectangular beams were tested under simply supported conditions with two-point loading up to failure. Beam dimensions are 150 mm × 200 mm × 1700 mm with flexural reinforcement (2ϕ10 at top and 3ϕ12 at bottom) and shear reinforcement (ϕ8@70 mm stirrups). Variables expected to affect strengthening system efficacy are discussed, specifically the type of fibers (carbon, glass, and basalt) and shape of elements (sheet, bar). Using different fiber types is an efficient method to enhance flexural strength of RC beams; capacity increased by 19.6% for NSM-FRP sheets and up to 107.6% for NSM-FRP bars. Strengthening with basalt, glass, and carbon NSM-FRP bars increased ultimate load by approximately 92.9%, 75.6%, and 107.6%, respectively, compared with the control beam. In contrast, NSM basalt, glass, and carbon sheets showed lower increases in ultimate load (about 11%, 16.3%, and 19.6%), respectively.

Abstract This study investigates the removal efficiency of various water contaminants using a Biological Sand Filtration (BSF) system under different operational conditions. The performance of the BSF system was evaluated for microbial contaminants (E. coli), suspended solids, dissolved solids (TDS), electrical conductivity (EC), hardness, chloride (Cl), sulfate (SO₄), and turbidity. Key operational parameters such as pH, retention time, flow rate, and the biological layer thickness were optimized to determine their impact on contaminant removal efficiency. The results demonstrated that a 48-hour retention time achieved complete E. coli removal (100%), while the 2 mm biological layer contributed to a significant reduction in microbial contaminants (81.2%). The highest turbidity reduction (85.4%) was achieved at a 0.5 m/h flow rate, and the pH 4.01 condition optimized the removal of TDS (65.4%) and EC (56.9%). Total hardness removal was maximized at 25°C, while magnesium removal was most effective with a 48-hour retention time (75.2%). Chloride removal peaked at 25°C (73.2%), and sulfate removal was optimized at pH 6.86 (52.9%). The study highlights the importance of adjusting operational parameters to optimize the performance of BSF systems for diverse contaminants, providing a sustainable and efficient solution for water quality improvement. The findings offer valuable insights for designing and operating BSF systems in varying environmental conditions and contribute to the development of cost-effective water treatment technologies.