Search Results (60)

Composite breakwater is a commonly employed structure for coastal and harbor protection. However, strong hydrodynamic impact can lead to failure and instability of these protective structures. In this study, a two-dimensional fluid-porous-solid coupling model is developed to investigate the stability of composite breakwaters. The fluid-porous model is based on the Volume-Averaged Reynolds-Averaged Navier-Stokes equations, in which the nonlinear Forchheimer equations are added to describe the porous layer. The solid model employs the Nodal-based Discontinuous Deformation Analysis (NDDA) method to analyze the displacement of the caisson. NDDA is a nodal-based method that couples FEM and DDA to improve non-linear processes. This proposed coupled model permits the examination of the influence of the thickness and porosity of the porous layer on maximum impacting wave height (${\mathrm{IWH}}_{\max }$) and the turbulent kinetic energy (TKE) generation. The results show that high porosity values lead to the dissipation of TKE and reduce the ${\mathrm{IWH}}_{\max }$. However, the reduction in the ${\mathrm{IWH}}_{\max }$ is not monotonic with increasing porous layer thickness. We observed that ${\mathrm{IWH}}_{\max }$ reaches an optimum value as the porous layer thickness continues to increase. These results can contribute to improve the design of composite breakwaters. Full article

This study develops a computational framework for the simultaneous quantification of seismic resilience and economic losses in corrosion-affected coastal continuous girder bridges. The proposed model integrates adjustment factors to reflect delays in post-earthquake repairs and cost increments caused by progressive material degradation. Finite element methods and nonlinear dynamic time-history simulations were conducted on an existing coastal continuous girder bridge to validate the proposed model. The key innovation lies in a probability-weighted resilience index incorporating damage state occurrence probabilities, which overcomes the computational inefficiency of traditional recovery function approaches. Key findings demonstrate that chloride exposure duration exhibits a statistically significant positive association with earthquake-induced structural failure probabilities. Sensitivity analysis reveals two critical patterns: (1) a 0.3 g PGA increase causes a 11.4–18.2% reduction in the resilience index (RI), and (2) every ten-year extension of corrosion exposure decreases RI by 2.7–6.2%, confirming seismic intensity’s predominant role compared to material deterioration. The refined assessment approach reduces computational deviation to ±2.4%, relative to conventional recovery function methods. Economic analysis indicates that chloride-induced aging generates incremental indirect losses ranging from $58,000 to $108,000 per decade, illustrating compounding post-disaster socioeconomic consequences. This work systematically bridges corrosion-dependent structural vulnerabilities with long-term fiscal implications, providing decision-support tools for coastal continuous girder bridges’ maintenance planning. Full article

Thousands of coastal reinforced concrete structures using HRB400 bars have served for over three decades in China. Their reinforcement simultaneously endures chloride corrosion and seismic action, yet studies on performance degradation remain limited. This paper investigates the low-cycle fatigue (LCF) behavior of HRB400 bars under various strain amplitudes, systematically analyzing corrosion morphology, cyclic stress–strain response, fatigue life, and underlying mechanisms. Corrosion is induced by an adjusted accelerated method that replicates field conditions. Observations reveal that corrosion pits act as primary crack initiation sites. Crack paths and fracture surfaces progressively follow the local pit geometry as strain and corrosion grow. The detrimental effect of corrosion on LCF life is more pronounced for smaller bars. At a γ of around 8%, 20 mm bars lose 60.7% of the half cycles to failure at ε = ±1.5%, but only 37.5% at ε = ±5.0%. Predictive corrosion-inclusive strain amplitude (ε_a)–fatigue life models are proposed, yielding R² = 0.952 (16 mm) and 0.928 (20 mm). A unified LCF predictive model, calibrated on a database of 310 corroded/uncorroded bar tests, is established. The final model comprehensively considers the characteristics of rebars, seismic action, and corrosion damage, improving the conventional relationship between LCF life and seismic loading. This work contributes to the understanding of the fatigue behavior of HRB400 bars and provides support for time-dependent seismic reliability analysis of aging reinforced concrete structures in corrosive environments. Full article

This study aims to develop a climate-resilient landscape design framework for coastal healthcare facilities by integrating Artificial Intelligence (AI)-generated design prompts with Computational Fluid Dynamics (CFD) simulations and on-site validation. Focusing on a coastal hospital in Penghu, Taiwan—a region vulnerable to strong winds, salt spray, and extreme weather—the research proposes a climate-adaptive, microclimate-responsive, and resilient design framework. Key findings demonstrate that the optimized design reduced average winter wind speed from 12 m/s to 4.5 m/s (a 62.5% reduction) and increased the three-year survival rate of salt-tolerant plant species (e.g., Pittosporum tobira, Casuarina) to 92%, significantly outperforming conventional planting strategies. The combination of water features and evapotranspiration planting reduced summer temperatures by 2.3 °C and increased humidity to 75%, with the PMV comfort index improving from +1.5 to +0.5. The program also resulted in a 15% increase in biodiversity, a 20% reduction in soil erosion, and a 40% improvement in users’ perceived aesthetic value of outdoor spaces. Furthermore, AI-based analyses to determine foundational depth led to a reduction in structural failure rates—from 40% to 5%—substantially elevating the safety and long-term durability of outdoor infrastructures. This study demonstrates that integrating AI with CFD is both feasible and highly effective for addressing complex coastal climate challenges in landscape architecture. The developed framework is parametric, evidence-based, and tailored to site-specific requirements, enabling the formulation of intelligent, climate-responsive landscape solutions for future healthcare environments in vulnerable coastal areas. Full article

A sheet pile wall is a widely used retaining structure in coastal and riverbank areas. In liquefiable soils, seismic activity can generate excess pore pressure, which not only increases the load on the sheet pile wall but also reduces the soil strength. Here, a modified stability analysis method is proposed to consider the effect of excess pore pressure on the stability of sheet pile walls. The excess pore pressure ratio was estimated through a pore pressure generation model and an equivalent number of loading cycles. In addition, two sets of dynamic centrifuge model tests were conducted on a liquefiable layer retained by a cantilevered sheet pile wall. The retained backfill experienced significant excess pore pressure, leading to the rotation failure of the sheet pile wall. The bending moments of the sheet pile wall were obtained using strain gauges, validating the effectiveness of the newly proposed stability analysis method. The dynamic water pressure in front of the wall can reduce the wall’s bending moment. When considering dynamic water pressure, the bending moment decreased by approximately 7.7%. For the same earthquake loading, varying the equivalent number of cycles did not affect the wall’s force response or the determination of instability. During the transition of the wall from static to unstable, the passive earth pressure in front of the wall extended deeper, causing a downward shift in the location of the maximum bending moment of the wall. Above all, this study provides a theoretical foundation for the design and construction of sheet pile walls in liquefiable regions. Full article

This paper presents a detailed analysis of the severe structural anomalies that led to the urgent rehabilitation of the Eduardo Caldeira Bridge in Machico, Madeira. Situated in a challenging coastal environment with complex volcanic geology, the bridge exhibited a critical failure of its bearing devices, which were assigned the highest defect severity rating (Grade 5). A multidisciplinary diagnostic methodology, combining visual inspection data, non-destructive testing, and geotechnical analysis, was employed to identify the root causes of this degradation. The investigation concluded that the bearing failure was not due to widespread material deterioration but was directly linked to significant lateral structural displacements, exacerbated by localized geotechnical instabilities. This paper details the data-driven rehabilitation strategy that was subsequently implemented, including the complete replacement of the bearings and substructure stabilization measures. The study provides a valuable case study of a complex, mechanics-driven failure mode and demonstrates that for such critical infrastructure, a proactive management model integrating advanced technologies like Structural Health Monitoring (SHM) and Building Information Modelling (BIM) is essential for ensuring long-term safety and resilience. Full article

Introduction: Congestive heart failure (CHF), a complex clinical syndrome characterized by the heart’s inability to pump blood effectively due to structural or functional impairments, is a growing public health concern, with profound implications for patients’ physical and emotional well-being. In India, the burden of CHF is rising due to aging demographics and increasing prevalence of lifestyle-related risk factors. Among the subtypes of CHF, heart failure with preserved ejection fraction (HFpEF), i.e., heart failure with left ventricular ejection fraction of ≥50% with evidence of spontaneous or provokable increased left ventricular filling pressure, and heart failure with reduced ejection fraction (HFrEF), i.e., heart failure with left ventricular ejection fraction of 40% or less and is accompanied by progressive left ventricular dilatation and adverse cardiac remodeling, may present differing impacts on health-related quality of life (HRQoL), i.e., an individual’s or a group’s perceived physical and mental health over time, yet comparative data remains limited. This study assesses HRQoL among CHF patients using the Minnesota Living with Heart Failure Questionnaire (MLHFQ), one of the most widely used health-related quality of life questionnaires for patients with heart failure based on physical and emotional dimensions and identifies sociodemographic and clinical variables influencing these outcomes. Methods: A cross-sectional analytical study was conducted among 233 CHF patients receiving inpatient and outpatient care at the Department of Cardiology at a quaternary care teaching hospital in coastal Karnataka in India. Participants were enrolled using convenience sampling. HRQoL was evaluated through the MLHFQ, while sociodemographic and clinical characteristics were recorded via a structured proforma. Statistical analyses included descriptive measures, independent t-test, Spearman’s correlation and stepwise multivariable linear regression to identify associations and predictors. Results: The mean HRQoL score was 56.5 ± 6.05, reflecting a moderate to high symptom burden. Patients with HFpEF reported significantly worse HRQoL (mean score: 61.4 ± 3.94) than those with HFrEF (52.9 ± 4.64; p < 0.001, Cohen’s d = 1.95). A significant positive correlation was observed between HRQoL scores and age (r = 0.428; p < 0.001), indicating that older individuals experienced a higher burden of symptoms. HRQoL also varied significantly across NYHA functional classes (χ² = 69.9, p < 0.001, ε² = 0.301) and employment groups (χ² = 17.0, p < 0.001), with further differences noted by education level, gender and marital status (p < 0.05). Multivariable linear regression identified age (B = 0.311, p < 0.001) and gender (B = –4.591, p < 0.001) as significant predictors of poorer HRQoL. Discussion: The findings indicate that patients with HFpEF experience significantly poorer HRQoL than those with HFrEF. Older adults and female patients reported greater symptom burden, underscoring the importance of demographic-sensitive care approaches. These results highlight the need for routine integration of HRQoL assessment into clinical practice and the development of comprehensive, personalized interventions addressing both physical and emotional health dimensions, especially for vulnerable subgroups. Conclusions: CHF patients, especially those with HFpEF, face reduced HRQoL. Key factors include age, gender, education, employment, marital status, and NYHA class, underscoring the need for patient-centered care. Full article

Roadway deformation failure is often related to the presence of weak structural planes (WSPs) in the surrounding rock mass. Especially in coastal mining environments, WSP-induced deformation can create pathways that connect faults with seawater, accelerating groundwater seepage and inrush hazards. This study employs an optimized Finite–Discrete Element Method (Y-Mat) to simulate WSP-driven fracture evolution, introducing an elastoplastic failure criterion and enhanced contact force calculations. The results show that the farther the WSP is from the roadway, the lower its influence; its existence alters the shape of the plastic zone by lengthening the failure zone along the fault direction, while its angle changes the shape and location of the failure zone and deflects fracture directions, with the surrounding rock between the roadway and WSP suffering the most severe failure. The deformation failure of roadway surrounding rock is influenced by WSPs. Excavation unloading reduces the normal stress and shear strength in the weak structural plane of surrounding rock, resulting in slip and deformation. Additionally, WSP-induced fractures act as groundwater influx conduits, especially in fault-proximal roadways or where crack angles align with hydraulic gradients, so mitigation in water-rich mining environments should prioritize sealing these pathways. The results provide a theoretical basis for roadway excavation and support engineering under the influence of WSPs. Full article

The proportion of granular ice in sea ice layers has markedly increased due to global warming. To investigate the uniaxial compressive behavior of granular sea ice, we conducted a series of experiments using natural piled and level ice samples collected from the Bohai Sea. A total of 311 specimens were tested under controlled temperature conditions ranging from −15 °C to −2 °C and strain rates varying from 10⁻⁵ to 10⁻² s⁻¹. The effects of porosity, strain rate, and failure modes were studied. The results show that both the uniaxial compressive strength and uniaxial compressive elastic modulus were dependent on strain rate and porosity. Granular sea ice exhibited a non-monotonic strength dependence on strain rate, with the strength increasing in the ductile regime and decreasing in the brittle regime. In contrast, the elastic modulus increased monotonically with the strain rate. Both the strength and elastic modulus decreased with increasing porosity. Level ice consistently demonstrated higher strength and an elastic modulus than piled ice at equivalent porosities. Unified parametric models were developed to describe both properties across a wide range of strain rates encompassing the ductile-to-brittle (DBT) regime. The experimental results show that, as porosity decreased, the transition strain rate of granular sea ice shifted from 2.34 × 10⁻³ s⁻¹ at high porosity (45%) to 1.42 × 10⁻⁴ s⁻¹ at low porosity (10%) for level ice and 1.87 × 10⁻³ s⁻¹ to 1.19 × 10⁻³ s⁻¹ for piled ice. These results were compared with classical columnar ice models. These findings are useful for informing the design of vessel and coastal structures intended for use in ice-covered waters. Full article

Coastal marine soft clays subjected to long-term storm wave loading often exhibit inclined initial principal stress orientation (α₀) and subsequent cyclic principal stress rotation (PSR). These stress states critically influence soil mechanical behavior and failure mechanisms, threatening offshore structural stability. This study employs hollow cylinder apparatus testing to investigate the undrained cyclic loading behavior of reconstituted soft clay under controlled α₀ and PSR conditions, simulating storm wave-induced stress paths. Results demonstrate that α₀ governs permanent pore pressure and vertical strain accumulation with distinct mechanisms, e.g., a tension-dominated response with gradual pore pressure rise at α₀ < 45° transitions to a compression-driven rapid strain accumulation at α₀ > 45°. Rotational loading with PSR significantly intensifies permanent strain accumulation and stiffness degradation rates, exacerbating soil’s anisotropic behavior. Furthermore, the stiffness degradation index tends to uniquely correlate with the permanent axial or shear strain, which can be quantified by an exponential relationship that is independent of α₀ and PSR, providing a unified framework for normalizing stiffness evolution across diverse loading paths. These findings advance the understanding of storm wave-induced degradation behavior of soft clay and establish predictive tools for optimizing marine foundation design under cyclic loading. Full article

The article presents an analysis of the complex mechanism of abrasion of shorelines built of non-lithified sediments as a result of rising water levels in the reservoir, along with its quantitative assessment. It allows forecasting the actual risks of coastal areas intendent for urbanization with similar morphology and geological structure. The task of the article is also to point out that for proper assessment of abrasion it is necessary to take into account the greater complexity of the mechanism in which abrasion is the result of co-occurring processes of erosion and landslides. During the analysis, the classic Kachugin method of abrasion assessment was combined with an analysis of the stability of the abraded slope, taking into account the circular slip surface (Bishop and Morgenster–Price methods) and the breaking slip surface (Sarma method). This approach required the assessment of the geotechnical properties of the soil using, among other things, advanced in situ methods such as static sounding. The results indicate that the cliff edge is in limit equilibrium or even in danger of immediate landslide. At the same time, it was possible to determine the horizontal extent of a single landslide at 1.2 to 5.8 m. In the specific cases of reservoir filling, the consideration of the simultaneous action of both failure mechanisms definitely worsens the prediction of shoreline sustainability and indicates the need to restrict construction development in the coastal zone. Full article

Transmission towers in coastal and industrial areas have experienced significant corrosion due to prolonged exposure to atmospheric pollutants and saline moisture, which poses a risk to structural safety. To evaluate the impact of corrosion depth on wind-induced collapse performance of an angle steel transmission tower, a survey of 18 angle steel towers in Ningbo, China, was conducted. Finite element models (FEMs) incorporating observed corrosion patterns were developed to analyze natural vibration characteristics and progressive collapse. The collapse modes of both corroded and uncorroded towers were identified, and high-risk failure member was determined. The results indicate that the corrosion depth below the lower cross-arm can be considered representative of the overall corrosion condition of the tower. Torsional natural frequency of the angle steel tower is particularly sensitive to corrosion due to the critical role of diagonal members. Collapse analysis further reveals that moderate corrosion levels can reduce the tower’s wind resistance to below the design threshold, potentially compromising safety under extreme weather conditions. The diagonal member below the lower cross-arm is identified as a high-risk failure component. Strengthening this member, by up-grading from L75×6 to L90×6, can significantly enhance the tower’s tolerance to corrosion. Full article

Calcareous sand, a critical construction material in reef engineering and building foundations, possesses unique internal microstructures and inherent mechanical properties. Given these characteristics, it is essential to thoroughly evaluate its strength under various loading conditions to ensure its reliability in building applications. This study examines the strength, deformation, and failure characteristics of calcareous sand through consolidated drained shear failure tests using a GDS stress path triaxial apparatus. The effects of shear rate, particle gradation, and compactness are systematically investigated to assess their impact on structural stability in building foundations and load-bearing applications. The results indicate that at low confining pressures, calcareous sand exhibits strain softening, whereas at higher confining pressures, strain hardening is observed. For samples with the same gradation, both peak deviatoric stress and failure strain increase linearly with confining pressure. The volume strain evolution during shear follows three stages: shear shrinkage, shear dilatancy, and stabilization. At low confining pressures, dilatancy is favored, while high confining pressures promote shrinkage. Additionally, under constant confining pressure, peak strength increases and failure strain decreases linearly with compactness. Increasing the loading rate from 0.01 to 0.1 mm/min results in a slight increase in the friction angle, with minimal impact on cohesion. Particle gradation plays a significant role in determining the shear strength of calcareous sand, as its effects vary depending on the combination of compactness and gradation. These findings provide valuable insights for the design and construction of stable building foundations, roadbeds, and other load-bearing structures in reef engineering and coastal developments, where calcareous sand is widely used. Full article

Concrete coating technology is a key measure that enhances the durability of concrete structures. This paper systematically studies the performance, applicability, and impact of different types of anti-corrosion coatings on concrete durability, focusing on their resistance to chloride ion penetration, freeze–thaw cycles, carbonation, and sulfate corrosion. The applicability of existing testing methods and standard systems is also evaluated. This study shows that surface-film-forming coatings can create a dense barrier, reducing chloride ion diffusion coefficients by more than 50%, making them suitable for humid and high-chloride environments. Pore-sealing coatings fill capillary pores, improving the concrete’s impermeability and making them ideal for highly corrosive environments. Penetrating hydrophobic coatings form a water-repellent layer, reducing water absorption by over 75%, which is particularly beneficial for coastal and underwater concrete structures. Additionally, composite coating technology is becoming a key approach to addressing multi-environment adaptability challenges. Experimental results have indicated that combining penetrating hydrophobic coatings with surface-film-forming coatings can enhance concrete’s resistance to chloride ion penetration while ensuring weather resistance and wear resistance. However, this study also reveals that there are several challenges in the standardization, engineering application, and long-term performance assessment of coating technology. The lack of globally unified testing standards leads to difficulties in comparing the results obtained from different test methods, affecting the practical application of these coatings in engineering. Moreover, construction quality control and long-term service performance monitoring remain weak points in their use in engineering applications. Some engineering case studies indicate that coating failures are often related to an insufficient coating thickness, improper interface treatment, or lack of maintenance. To further improve the effectiveness and long-term durability of coatings, future research should focus on the following aspects: (1) developing intelligent coating materials with self-healing, high-temperature resistance, and chemical corrosion resistance capabilities; (2) optimizing multilayer composite coating system designs to enhance the synergistic protective capabilities of different coatings; and (3) promoting the creation of global concrete coating testing standards and establishing adaptability testing methods for various environments. This study provides theoretical support for the optimization and standardization of concrete coating technology, contributing to the durability and long-term service safety of infrastructure. Full article

The service of reinforced concrete structures (RCSs) in harsh coastal environments is often threatened by chloride corrosion. The penetration of chloride ions through concrete pores into the steel/concrete interface will cause the depassivation and corrosion of steel rebars, which will lead to the deterioration and failure of RCSs durability. It is important to repair and protect the corrosion damage of existing concrete structures and ensure their high durability, and the high performance of repairing and protecting materials is crucial. In this paper, a novel cement-based protective coating material with low porosity, high impermeability and chloride-corrosion resistance was designed and prepared by introducing polypropylene fiber and high-performance cement into commercial cement-based protective materials through the double modification strategy of fiber-toughening and substrate-enhancing, in order to provide a reliable corrosion protection solution for the high durability and long life of RCSs under chloride erosion environment. Based on this, the microstructure and pore structure of the double-modified coating material was systematically analyzed by SEM, XRD, X-CT and other characterization methods. The impermeability and chloride corrosion resistance of this material were scientifically evaluated, and the protection mechanism was systematically discussed. The results show that the impermeability of the double-modified coating material is about 2.8 times higher than that of the untreated mortar. At the same time, the corrosion current density was significantly reduced to 8.60 × 10⁻⁷ A·cm⁻², which was about 86% lower than that of the untreated sample (6.11 × 10⁻⁶ A·cm⁻²). The new cement-based coating material optimized by double-modification effectively inhibits the formation and propagation of microcracks in the protective coating through the bridging effect of fibers. At the same time, the regulation of cement hydration products and the densification of pore structure are realized by adjusting the composition of cement matrix. Based on the above two aspects of microstructure improvement, the chloride-corrosion protection performance of the novel cement-based protective coating material has been greatly improved. Full article