The scouring of cohesive and non-cohesive materials downstream of sluice gates is primarily based on high-velocity flow. The present study considered an experimental hydraulic model of submerged water flow issuing from a sluice gate installed on an apron that leads to the scour hole and dune in a downstream mixture of sand and clay bed. The purpose was to achieve a suitable efficiency of the weight ratio of clay in the sand–clay mixture (c) for the sediment bed. Scour parameters, including maximum scour depth (dse) and its longitudinal location (xse), and maximum dune height (hd) and its location (xd), were measured and compared for three variations, c = 0.1, 0.2, and 0.3, under five hydraulic conditions. Results revealed that all scour parameters were reduced by adding clay to the sand soil, and the maximum reduction was for dse with the maximum value of 27.66%. The observed data were analyzed by multiple nonlinear regression analyses for each scour parameter to present new prediction equations for practical uses. The computed statistical parameters of correlation coefficient (R2), root mean square error (RMSE), mean absolute percentage error (MAPE), Nash–Sutcliffe efficiency (NSE), and scatter index (SI) present good accuracy for the predicted equations in the ranges of experimental data.

To systematically investigate the issues of tunnel overheating and excessive humidity, this study integrates theoretical analysis, experimental research, and numerical simulations. It examines the coupled heat and moisture transfer behavior in the surrounding rock of metro tunnels and its impact on the tunnel’s thermal and humid environment. Based on the theory of heat and moisture transport in porous media, a coupled mathematical model is developed using relative humidity and temperature gradients as the driving potentials. Taking into account the climatic zoning of China, Beijing, Shanghai, Guangzhou, and Kunming are selected as representative cities for cold, hot summer/cold winter, hot summer/warm winter, and temperate climate regions, respectively. The interannual variation characteristics of the thermal and humidity conditions inside metro tunnels in these cities are analyzed and compared. The results indicate that across different climatic zones, higher outdoor peak air temperatures lead to higher peak air temperatures inside the tunnels. The thickness of the thermal regulation zone is primarily influenced by the initial rock temperature and the annual average atmospheric temperature. The thickness of the moisture regulation zone is affected by both the annual temperature fluctuation and the annual average relative humidity, increasing with greater annual atmospheric temperature variation.

Slender, lightweight and modern footbridges are particularly susceptible to vibrations induced by pedestrian activity. While extensive research has focused on vertical and lateral forces produced by walking, torsional moments generated by eccentrically walking pedestrians remain largely overlooked. Traditional assessments typically neglect these torsional effects, which can be critical when eccentric pedestrian loading excites torsional modes, especially in footbridges with asymmetric geometries. To address this, the paper considers the coupling between bending and torsional effects in both the pedestrian action and structure reaction, including pedestrian forces and moments, as well as bending-induced deflections and torsion-induced rotations of the cross-sections. A simplified method is also presented, allowing standard bending-only analyses to be easily adapted to include torsional effects using analytically derived correction factors. For validation, several experimental tests are conducted on an asymmetric curved footbridge located in Modena, Italy, characterised by coupled bending-torsional vertical modes and hosting different pedestrian densities, pacing frequencies, and crowd distributions (both uniform and eccentric). Experimental and numerical analyses demonstrate that neglecting torsional effects oversimplifies the assessment, highlighting the importance of accounting for bending-torsion coupling for the serviceability of asymmetric footbridges under eccentric near-resonance loading.

To ensure the coordinated interaction between the beam and track of large-span bridges and achieve smooth rail transition at beam joints, rail expansion regulators and beam-end expansion devices are essential at bridge ends. However, these devices are structurally fragile, making them a weak link in the seamless track system. This study selected a long-span railway bridge and its expansion devices as research objects, summarized typical in-service diseases of beam-end expansion devices (e.g., adjustable sleeper offset, sleeper skewing, and expansion device jamming), and constructed a train–track–bridge coupled model incorporating these devices. The model was used to analyze the structural performance and train operation safety under defective conditions. Based on the analysis findings, a maintenance evaluation method for the beam-end region was proposed. Criteria include adjustable sleeper offset, lateral displacement difference between adjacent beam-ends, horizontal rotation angle of adjacent beams, vertical rotation angle of beam-ends, and longitudinal expansion amount of beam-end expansion devices in order to address the corresponding issues and achieve sustainable maintenance and operation of bridge structures.

Shear lag is the phenomenon that occurs when a supported slender member undergoes deformation from lateral loading, causing in-plane non-uniform distribution of stresses that results in reducing the member’s minimum strength capacity. This paper investigates the behaviour of shear distribution in steel I-section and box girders when subjected to both static and impact loadings. Three-dimensional finite element analysis models were prepared in Strand7 and validated against experimental results providing a basis for further comparison research into shear lagging effects. A parametric study was conducted comparing the effects of impact loading through certain specified velocities at the midspan of restrained ends. It provided new insights into the distribution of shear lag and prevalence of loading locality when considering unique impact scenarios. Impact loads provided different shear-lag results compared to static loads as the material’s properties absorb energy through deformation and distribution of stress. Furthermore, the study highlights the need for additional investigation into a variety of impact scenarios and possible factors for designers to consider when implementing members in structures.

In this study, a three-dimensional nonlinear finite element (FE) model was developed using Abaqus/Explicit to simulate the effects of internal blasts. The numerical model was validated against two previously published numerical and experimental works, demonstrating strong agreement in deformation results. A parametric study was carried out to evaluate the influence of several key factors on the deformation of the receiver tunnel subjected to an explosion in the adjacent donor tunnel. The investigation considered critical variables such as lining material, tunnel inner diameter, cross-sectional shape, spacing between tunnels, and TNT charge weight. The results clearly indicate that expanded polystyrene (EPS) foam, across various densities, demonstrates superior capacity for absorbing blast waves compared to polyurethane and aluminum foams. Furthermore, it was found that lower-density EPS foam provides enhanced mitigation of deformation in tunnel linings. The findings also revealed that damage to the tunnel walls is more strongly correlated with the tunnel shape where the circular tunnel exhibited the best performance. It showed the lowest deformation and delayed peak response. In addition, tunnel deformation increases markedly with higher TNT charge weights. A blast of 1814 kg produced approximately five times the deformation compared to a 454 kg charge. Moreover, it is seen that increasing the spacing between donor and receiver tunnels from 1.5 D to 2.5 D led to a 38.7% reduction in maximum deformation.

The growing environmental effect of asphalt pavements has fueled interest in sustainable alternatives including the application of recycled materials and self-healing systems. This research investigates the synergistic possibilities of steel slag aggregates and steel wool fibers in hot-mix asphalt compositions to increase sustainability and let crack healing via electromagnetic induction heating. Using either recycled steel slag or natural porphyritic aggregates, two kinds of AC16 Surf S mixtures with 35/50 bitumen were created incorporating two levels of steel fiber content (2% and 4%). Based on repeated semi-circular bending (SCB) testing following regulated induction heating and confinement, a committed self-healing evaluation plan was developed. The results verified that combinations including recycled steel slag met or outperformed traditional mixes in terms of mechanical behavior. Induction heating successfully set off partial recovery of fracture toughness, with more fiber content and repeated heating cycles producing better healing values. Recovery levels ran from 14.6% to 40%, therefore proving the practicality of this approach. These results encourage the creation of asphalt mixtures with improved endurance and environmental advantages. The research offers both an approved approach for assessing healing and real-world recommendations for the construction of low-maintenance, round pavements utilizing induction-based techniques.

Accessibility and the so-called ‘15 min city’ paradigm are critical dimensions in agendas involving urban policies. However, when interested in accounting for accessibility from a formal perspective, researchers and practitioners should use pertinent indicators. Additionally, most of the indicators focus on the number of facilities reachable within a given time window, while the counterpart of the latter, i.e., as a measure of attractiveness, such as the number of users that can reach that given area, is not evaluated explicitly. In this paper, a comprehensive method able to capture accessibility and attractivity simultaneously will be presented. The formulation is based on a refinement of the gravity model. As the main input, the actual number of residents was used and included in the computation. Therefore, the resulting values of accessibility and attractivity are intended to represent the real status of different degrees of walkable accessibility in urban areas. As a test field, three Italian cities were explored. The method proposed and discussed throughout the paper is aimed at providing an operative tool for planners, as well as for private stakeholders, when they are in charge of evaluating the degree of ‘walkable’ accessibility. Furthermore, the use of open and standardized data is intended to be a main strength of the proposed methodology, as it can be easily replicated in other contexts.

Pavement condition assessment using computer vision has emerged as an efficient alternative to traditional manual surveys, which are often labor-intensive and time-consuming. Leveraging deep learning, pavement distress such as cracks can be automatically detected, segmented, and quantified from high-resolution images captured by survey vehicles. Although numerous segmentation models have been proposed to generate crack masks, they typically require extensive pixel-level annotations, leading to high labeling costs. To overcome this limitation, this study integrates the Segmentation Anything Model (SAM), which produces accurate segmentation masks from simple bounding box prompts while leveraging its zero-shot capability to generalize to unseen images with minimal retraining. However, since SAM alone is not an end-to-end solution, we incorporate YOLOv8 for automated crack detection, eliminating the need for manual box annotation. Furthermore, the framework applies local refinement techniques to enhance mask precision and employs Optical Character Recognition (OCR) to automatically extract embedded GPS coordinates for geospatial mapping. The proposed framework is empirically validated using open-source pavement images from Yamanashi, demonstrating effective automated detection, classification, quantification, and geospatial mapping of pavement cracks. The results support automated pavement distress mapping onto real-world road networks, facilitating efficient maintenance planning for road agencies.

Distributed fiber-optic sensing (DFOS) with intentionally spaced mechanical fixity points was experimentally evaluated for the structural health monitoring (SHM) of reinforced concrete (RC) members. A full-scale four-point bending test was conducted on a 12 m RC beam (400 × 400 mm) instrumented with a single-mode DFOS cable incorporating internal anchors at 2 m intervals and bonded externally with structural epoxy. Brillouin time-domain analysis (BOTDA) provided distributed strain measurements at approximately 0.5 m spatial resolution, with all cables calibrated to ±15,000 µε. Under stepwise monotonic loading, the system captured smooth, repeatable strain baselines and clearly resolved localized tensile peaks associated with crack initiation and propagation. Long-gauge averages exhibited a near-linear load–strain response (R2 ≈ 0.99) consistent with discrete foil and vibrating-wire strain gauges. Even after cracking, the DFOS signal remained continuous, while some discrete sensors showed saturation or scatter. Temperature compensation via a parallel fiber ensured thermally stable interpretation during load holds. The fixed-point configuration mitigated local debonding effects and yielded unbiased long-gauge strain data suitable for assessing serviceability and differential settlement. Overall, the results confirm the suitability of fixed-point DFOS as a durable, SHM-ready sensing approach for RC foundation elements and as a dense data source for emerging digital-twin frameworks.