Search Results (49)

Rectangular aqueducts are critical building structures in large-scale water conveyance systems used worldwide. Liquid sloshing can produce hydrodynamic forces that threaten structural safety and long-term performance. This study analytically investigates the vibration characteristics of two-dimensional rectangular cantilever aqueduct systems while accounting for soil–structure interaction (SSI). To reduce sloshing and enhance the performance of the mechanical system, a bottom-mounted vertical baffle is proposed as a hydrodynamic damping solution. Through subdomain analysis, mathematical expressions for liquid potential fields are derived. The continuous liquid is represented through discrete mass–spring elements for dynamic analysis. Horizontal soil impedance is characterized by using Chebyshev orthogonal polynomial approximations with optimized least squares fitting techniques. A dynamic mechanical model for the soil–aqueduct–liquid–baffle coupling system is developed by using the substructure method. Convergence and comparative studies are conducted to validate the reliability of the proposed method. Between the current results and those reported previously, the variation in the first-order sloshing frequency is less than 1.10%. Parametric analyses evaluate how baffle size, baffle position, and soil properties influence sloshing behavior. The presentation of an equivalent analytical model is the novelty of this research. The results can provide the theoretical basis for optimizing anti-sloshing designs in hydraulic building structures, thereby supporting safer and more sustainable engineering practices. Full article

Background: The inner ear hosts several macrophage populations. Endolymphatic sac macrophages can phagocytose otoconia, and spiral limbus macrophages express genes for fluid shear stress sensing and bone remodeling. Obstruction of endolymph flow by saccular otoconia could be linked to endolymphatic hydrops. Since macrophages are strongly affected by inflammatory status, a role for them in otolith removal could provide a link between inflammation and hydrops. However, the distribution of macrophages around the reuniting duct (RD) and endolymphatic duct (ED), which are narrow structures likely prone to blockage, remains unexplored. Methods: We performed tissue clearing and light-sheet imaging on rat temporal bones. Autofluorescence and immunolabeling for collagen IV, smooth muscle actin, and Iba1 were used to visualize inner ear structures, blood vessels, and macrophages. Results: The connective tissue layer underlying the RD extended from the cochlear spiral limbus. The RD and spiral limbus hosted a continuous microvascular network and macrophage population, comprising both ameboid and ramified cells; macrophages also surrounded the underlying vestibulocochlear artery (VCA). A separate macrophage population, continuous with that of the saccular connective tissue, was found around the endolymphatic sinus and utriculo–endolymphatic (Bast’s) valve; macrophage patterns changed in the vestibular aqueduct and endolymphatic sac. Conclusions: Macrophages are observed in positions consistent with potential roles in sensing luminal changes and in the clearance of obstructive material from the RD and ED; functional confirmation will require targeted experiments. Full article

Heavy rainfall infiltration is a key disaster-inducing factor that triggers the softening of surrounding rock and deformation of support structures in tuff gully tunnels. Based on the gully section of the left line of the Dabao Tunnel of the Leigongshan–Rongjiang Expressway in Guizhou Province, this study systematically reveals the synergistic disaster-inducing mechanism of “topography-seepage-softening” in tuff gully tunnels under heavy rainfall infiltration through laboratory tests and FLAC3D 3D numerical simulations. The main innovative conclusions are as follows: (1) The “phased” attenuation law of tuff mechanical parameters was quantified, and the critical water content for significant strength deterioration was determined to be 2.5%, with a saturated softening coefficient of 0.59. These results provide key data for early warning and evaluation of similar projects. (2) A “convergence-disorder” distribution pattern of pore water pressure controlled by gully topography was revealed. It was found that the rock mass directly below the aqueduct exhibits a disordered zone with downward-extending pore water pressure due to fluid convergence, with the maximum pore water pressure reaching 0.55 MPa. This clarifies the essence that tunnel stability is controlled by the coupling of topography and seepage field. (3) The key sensitive areas for tunnel stability—namely the gully bottom, arch haunches, and the area below the aqueduct—were accurately identified. The significant increase in displacement of these areas after rock stratum softening was quantified (e.g., the displacement at the crown of the secondary lining increased from 3 mm to 4 mm, and the influence range expanded to the arch haunches). This study clarifies the deformation characteristics and instability mechanism of tuff gully tunnels under heavy rainfall from two aspects: the “internal mechanism of rock mass softening” and the “external condition of topographic seepage control.” It can provide a theoretical basis and key technical pathway for disaster prevention and control as well as stability design of similar tunnels. Full article

This study uses a U-shaped aqueduct structure in a specific irrigation area as the research object to examine the damage patterns of large-span elevated U-shaped aqueduct structures under seismic action. A single-span aqueduct model that integrates fluid–structure interaction is created with the finite element program ANSYS. The incremental dynamic analysis approach is utilized to perform nonlinear dynamic time–history assessments for three types of bearings—plate rubber bearings, pot rubber bearings and lead-core rubber bearings—under conditions of an empty condition, a half-full condition and a design water level. Seismic fragility curves for the bearings and piers subjected to transverse seismic stress are developed using capacity–demand ratio models and specified damage limit states. The findings demonstrate that the likelihood of aqueduct components being damaged increases substantially as seismic intensity increases, with bearings failing before piers. Under the conditions of empty, half-full and design water levels, the structural mass increases as a result of higher water levels. This alters the dynamic response characteristics and increases the likelihood of failure in a variety of damage states. The probability of plate rubber bearings experiencing minor damage exceedance increases from 11.75% to 61.6% as the water level rises from vacant to design conditions. Lead-core rubber bearings provide better seismic isolation than plate rubber bearings and pot rubber bearings. This greatly lowers the aqueduct structure’s displacement response and damage likelihood. Under design water level circumstances, the chance of mild damage to lead rubber bearings is 8.64%, at a peak ground acceleration of 0.4 g. The damage probabilities for the pot rubber bearings and the plate rubber bearings are 80.68% and 97.45%, respectively. The research findings establish a theoretical foundation for the seismic design and damage evaluation of aqueduct structures in places with high seismic activity, ensuring the stable operation of water transfer projects and sustainable water resource utilization, presenting considerable technical applicability. Full article

The performance evaluation of aqueducts is crucial for the development of water conservancy and the protection of cultural relics. However, there are few effective methods for accurate evaluations of the mechanical performance of aqueducts. To investigate the changes in the concrete microstructure during the service life of aqueducts, this study conducted compressive tests on various parts of an aqueduct that has been in service for 56 years in Hunan Province, China. Additionally, scanning electron microscopy (SEM) scans and mercury intrusion porosimetry (MIP) tests were carried out on concrete samples taken from the side and bottom of the aqueduct tank. The compressive strength of the aqueduct concrete was 28.3–44.1 MPa, and the porosity of concrete was 10.98–17.57%. The pore structure of concrete is deteriorated by carbonation and water flow, which has a negative impact on the impermeability of the aqueduct. For concrete at the bottom of the tank, the internal pore structure was denser than the external one (with lower porosity and smaller average pore diameter). In contrast, the pore structure in other parts was the opposite. This difference was caused by the presence of flowing water. The types of internal pores in the concrete are basically gel pores and capillary pores. Finally, evaluation models considering the relationships between carbonation, compressive strength, porosity and permeation parameters of aqueduct concrete were proposed. The models can provide theoretical support for the performance evaluation and maintenance of aged aqueducts. Full article

This study presents a comprehensive analysis of hydration heat-induced temperature and stress fields in a U-shaped aqueduct during the casting phase, integrating field measurements and numerical simulations. The key findings are as follows: (1) Thermal Evolution Characteristics: Both experimental and numerical results demonstrated consistent thermal behavior, characterized by a rapid temperature rise, subsequent rapid cooling, and eventual stabilization near ambient conditions. The peak temperature is observed at the centroid of the bearing section’s base slab, reaching 83.8 °C in field tests and 87.0 °C in simulations. (2) Stress Field Analysis: Numerical modeling reveals critical stress conditions in the outer concrete layers within high-temperature zones. The maximum tensile stress reaches 6.37 MPa, exceeding the allowable value of the tensile strength of the current concrete (1.85 MPa) by 244%, indicating a significant risk of thermal cracking. (3) Temperature Gradient and Cooling Rate Anomalies: Both methodologies identify non-compliance with critical control criteria. Internal-to-surface temperature differentials exceed the 25 °C threshold. Daily cooling rates at monitored locations surpass 2.0 °C/d during the initial 5–6 days of the cooling phase, elevating cracking risks associated with excessive thermal gradients. (4) Mitigation Strategy Proposal: Implementation of a hydration heat control system is recommended; compared to single-layer systems, the proposed mid-depth double-layer steel pipe cooling system (1.2 m/s flow) reduced peak temperature by 23.8 °C and improved cooling efficiency by 28.7%. The optimized water circulation maintained thermal balance between concrete and cooling water, achieving water savings and cost reduction while ensuring structural quality. (5) The cooling system proposed in this paper has certain limitations in terms of applicable environment and construction difficulty. Future research can combine with a BIM system to dynamically control the tube cooling system in real time. Full article

At the beginning of human history, surface water, especially from rivers and springs, was the most frequent water supply source. Groundwater was used in arid and semi-arid regions, e.g., eastern Crete (Greece). As the population increased, periodic water shortages occurred, which led to the development of sophisticated hydraulic structures for water transfer and for the collection and storage of rainwater, as seen, for example, in Early Minoan times (ca 3200–2100 BC). Water supply and urban planning had always been essentially related: the urban water supply systems that existed in Greece since the Bronze Age (ca 3200–1100 BC) were notably advanced, well organized, and operable. Water supply systems evolved considerably during the Classical and Hellenistic periods (ca 480–31 BC) and during the Roman period (ca 31 BC–480 AD). Also, early Indian society was an amazing vanguard of technology, planning, and vision, which significantly impacted India’s architectural and cultural heritage, thus laying the foundation for sustainable urban living and water resource management. In ancient Egypt, the main source of freshwater was the Nile River; Nile water was conveyed by open and closed canals to supply water to cities, temples, and fields. Underground stone-built aqueducts supplied Nile water to so-called Nile chambers in temples. The evolution of water supply and urban planning approaches from ancient simple systems to complex modern networks demonstrates the ingenuity and resilience of human communities. Many lessons can be learned from studying traditional water supply systems, which could be re-considered for today’s urban sustainable development. By digging into history, measures for overcoming modern problems can be found. Rainwater harvesting, establishing settlements in proximity of water sources to facilitate access to water, planning, and adequate drainage facilities were the characteristics of ancient civilizations since the ancient Egyptian, Minoan, Mohenjo-Daro, Mesopotamian, and Roman eras, which can still be adopted for sustainability. This paper presents significant lessons on water supply around the world from ancient times to the present. This diachronic survey attempts to provide hydro-technology governance for the present and future. Full article

In recent years, the number of incidents involving aqueduct damage due to vehicle impact has steadily increased, significantly affecting the safe operation of water transfer projects. To investigate the dynamic response characteristics of aqueduct structures under vehicle impact, a numerical model of vehicle impact on an aqueduct was developed using ANSYS/LS-DYNA software. The influence of impact eccentricity and concrete strength on the dynamic response of the aqueduct structure was then analyzed. The results indicate that the aqueduct bent frame exhibits a pronounced torsional response under eccentric impact, exacerbating the damage and deformation of the aqueduct structure. The peak impact force is positively correlated with concrete strength, whereas the maximum lateral displacement and residual displacement at the top of the impacted bent frame show a negative correlation with concrete strength. Finally, three anti-collision measures are proposed: a rubber concrete outer box with a rubber filling layer, an ultra-high-performance concrete (UHPC) outer box with a foam aluminum filling layer, and a rubber concrete outer box with a foam aluminum filling layer. The energy dissipation, internal force response, displacement response, and aqueduct damage characteristics of these measures are compared and analyzed, and compared to the aqueduct structure without anti-collision measures, the peak impact force is reduced by at least 17%. The lateral residual displacements at the bottom, the impact area, and the top of the aqueduct bent frame are reduced by at least 88.3%, 97.8%, and 88.5%. The damage and severity of damage to the aqueduct are significantly reduced, providing valuable insights for the anti-collision design of aqueducts. Full article

We review the research on L. fortunei over the past 22 years, systematically elucidating its impacts on ecological environments and water engineering structures. We explored the effects of external factors on the invasion and spread of L. fortunei, as well as the internal factors that impact the ecological environment and water engineering structures. We also provide new perspectives and directions for L. fortunei control. The major research findings include the following: (1) L. fortunei negatively impacts hydraulic structures, being hard to remove and capable of damaging them, disrupting normal operations. (2) L. fortunei’s ecological impact is multifaceted: it reduces water cloudiness and organic matter by filtering suspended particles and depositing feces, but its decay after death consumes dissolved oxygen, increasing chemical oxygen demand and lowering water quality. (3) L. fortunei control techniques are effective for localized use in small bodies of water and aqueducts, but their control in large open reservoirs is difficult to achieve with one method. Existing control methodologies for L. fortunei were systematically evaluated across multiple dimensions, including engineering applicability and feasibility, technical advantages and limitations, and economic cost-effectiveness. This comprehensive analysis establishes a decision-support framework for optimizing control strategy selection in diverse engineering scenarios and application contexts. Full article

This study presents part of a pilot work for the structural health monitoring of a large tied-arch reinforced concrete aqueduct in eastern China. Based on field-monitored data for over a year, it mainly focuses on the effect of air temperature and water load variations on the static behavior of a typical span of the aqueduct through field monitoring and 3D FE model analysis. It is found that the longitudinal deformation of the composite tied-arch shows a good linear relationship with the air temperature during the non-operation period and also has a good bilinear correlation with the air temperature and water level during operation. However, isolation of the air temperature effect from the second bilinear correlation using the first linear relationship results in a poor correlation between the longitudinal deformation and water level due to the dominance of the temperature effect. Therefore, it is recommended to use the bilinear regression to predict the longitudinal deformation of the tied-arch during operation. The vertical deformation of the tied-arch is insignificantly affected by air temperature, whereas it shows a fair bilinear correlation with the air temperature and water level during operation, which can be used to provide a reasonable estimation of the vertical deformation of the tied-arch. The strain measurements of the tied-arch using vibrating-string gauges are more complicated due to the notable influence of the ambient temperature and solar radiation, but the relatively consistent bilinear regression of the strains versus the air temperature and water level can still give fair predictions for the strains of the bottom tension rods during operation. The 3D FE model can provide a fair estimation for the vertical deformation of the tied-arch under water load, but its predictions for longitudinal deformation and strains are less satisfactory when compared to monitored data excluding temperature effects. Full article

Water transport pipelines in the mining industry face significant corrosion challenges due to extreme environmental conditions, such as arid climates, temperature fluctuations, and abrasive soils. This study evaluates the effectiveness of three advanced inspection technologies—Guided Wave Ultrasonic Testing (GWUT), Metal Magnetic Memory (MMM), and In-Line Inspection (ILI)—in maintaining pipeline integrity under such conditions. A structured methodology combining diagnostic assessment, technology research, and comparative evaluation was applied, using key performance indicators like detection capability, operational impact, and feasibility. The results show that GWUT effectively identifies surface anomalies and wall thinning over long pipeline sections but faces depth and diameter limitations. MMM excels at detecting early-stage stress and corrosion in inaccessible locations, benefiting from minimal preparation and strong market availability. ILI provides comprehensive internal and external assessments but requires piggable pipelines and operational adjustments, limiting its use in certain systems. A case study of critical aqueducts of mining site water supply illustrates real-world technology selection challenges. The findings underscore the importance of an integrated inspection approach, leveraging the complementary strengths of these technologies to ensure reliable pipeline integrity management. Future research should focus on quantitative performance metrics and cost-effectiveness analyses to optimize inspection strategies for mining infrastructure. Full article

Workplace safety, particularly in the construction industry, is a moral and legal imperative, prioritizing the protection of workers’ health and well-being. In Italy, Legislative Decree 81/08 (and subsequent modifications) serves as a regulatory framework for workplace safety, defining the duties of employers and employees and promoting accident prevention measures. Building information modeling technology, which has revolutionized the global construction industry by offering an integrated approach to design, construction, and management through intelligent digital models, has only recently started gaining traction in Italy as part of Industry 4.0. This article examines the potential of integrating the current prevention strategies with BIM technology to optimize safety design on construction sites. A case study demonstrates the use of the BIM software REVIT to model a water reservoir for an aqueduct, including structural and plant components, the surrounding context, and proposed construction site organization. The research methodology involves creating a contextualized 3D model to support preliminary safety assessments, work process organization, and the drafting of a safety and coordination plan. Through detailed analysis and critical discussion, this work contributes to understanding how the interaction of regulations and BIM technology can improve construction site safety, offering insights that are applicable beyond the Italian context to the global construction industry. Full article

This study proposes a time-dependent reliability analysis method for aqueduct structures based on concrete carbonation and finite element analysis. The primary goal of this study is to improve the reliability assessment of reinforced concrete aqueducts by incorporating environmental factors such as carbonation over time. First, a three-dimensional finite element model of a reinforced concrete aqueduct is established using the Midas 2022 Civil software, incorporating a time-varying function derived from a predictive model of concrete carbonation depth. Point estimation is then integrated with structural finite element analysis to calculate the first four moments of random variables as functions of concrete carbonation. Additionally, the original performance function is transformed into a normal distribution using dual power transformation and the Jarque–Bera test. The high-order unscented transformation (HUT) is subsequently employed to estimate the first four moments of the transformed performance function, facilitating the calculation of time-varying reliability indices for the carbonated concrete aqueduct. Based on the time-varying reliability index data, a reliability function corresponding to different time points is fitted and applied to service life prediction. The results demonstrate that the proposed method effectively reduces large errors associated with the fourth-moment method in calculating large reliability indices. Furthermore, the comparison with Monte Carlo simulation (MCS) results validates the high efficiency and accuracy of the proposed method, offering a valuable tool for addressing the reliability challenges of aqueducts exposed to carbonation and other environmental factors over time. Full article

Objectives: Congenital hearing loss is a significant health concern, with diverse etiologies encompassing cochlear and cochleovestibular pathologies. Preoperative radiological evaluation in cochlear implant candidates is pivotal for treatment planning. We aim to elucidate the spectrum of radiological findings in patients with congenital hearing loss undergoing cochlear implant assessment. Methods: An analysis included 389 sensorineural hearing loss (SNHL) patients who underwent cochlear implantation at a tertiary university hospital, of which 177 were congenital SNHL. Computed tomography (CT) and magnetic resonance imaging (MRI) data were meticulously assessed for diverse congenital pathologies, focusing on congenital malformations. Results: In the congenital SNHL group, comprising 177 patients (80 females and 97 males), congenital cochleovestibular malformations were evident in 56 ears of 29 cases. Different congenital cochleovestibular malformations, ranging from labyrinthine aplasia to isolated large vestibular aqueducts, were detected. Among the various anomalies, incomplete partitions and cochlear hypoplasia emerged as more frequent patterns. Conclusions: This study offers a comprehensive radiological analysis of congenital SNHL patients undergoing cochlear implantation, revealing a spectrum of anomalies. It demonstrates the diverse nature of anomalies affecting the external auditory canal, middle ear structures, and cochleovestibular system. These insights provide a deeper understanding of congenital SNHL and contribute to developing informed treatment strategies. Full article

To address the issue of regional water resource scarcity, water diversion projects have been constructed worldwide. As an essential lifeline project, the prefabricated aqueduct is prevalently utilized in cross-regional water transfer and diversion projects. This paper was based on the prefabricated aqueduct project, which adopted fabricated technologies including the connection technology among the gravity pier, the prefabricated arch ribs, and the prefabricated bent frame columns. The PHC piles, bearing platforms, bent frame columns, arch ribs, and groove bodies were all prefabricated components that were transported to the site for installation. The connections of the prefabricated aqueduct employed to link different components were of such crucial significance that their safety and stability determined whether the overall structure would be compromised. Therefore, the main objective of this paper was to examine the stress and deformation of this prefabricated aqueduct to prevent the occurrence of security risks throughout the entire construction stage. The finite element model was established in Midas Civil, and the entire construction stage was simulated and analyzed. Coupled with on-site monitoring, the stress and deformation of the prefabricated aqueduct were evaluated. The results indicated that the tensile stress, the compressive stress, the vertical displacement, and the lateral displacement of each part of the prefabricated aqueduct met the requirements of the standard, suggesting that the overall structure with the applied connection technology was in a safe and stable state throughout the entire construction stage. Full article