为探究拉(缆)索护套破损尺寸对索内高强钢丝腐蚀扩散模式以及缆索承载性能的影响规律，本研究首先采用人工加速腐蚀试验模拟不同开口尺寸下拉索索内钢丝腐蚀扩散模式。之后，对锈蚀后的钢丝进行腐蚀等级评估，建立钢丝腐蚀扩散三维数学模型。最后，对锈蚀高强钢丝进行力学试验，探究非均匀锈蚀下高强钢丝的力学性能退化规律及其与截面损失率间的关系，结合腐蚀三维扩散模型建立拉索剩余承载力评估模型，评估拉索承载力。研究结果表明：腐蚀初期，护套开口尺寸对索内钢丝腐蚀扩散速度影响显著，随着腐蚀时间的延长，开口尺寸的影响逐渐减小；通过COMSOL有限元软件验证腐蚀扩散模型，结果显示本腐蚀扩散模型可较准确地表征索内钢丝的腐蚀扩展规律；根据拉索承载力模型计算得腐蚀4周后，20mm和30mm开口尺寸的拉索承载力退化明显，当腐蚀12周时，30mm开口尺寸拉索的外层钢丝锈蚀率大于12％，拉索剩余承载力低于规范限值。

Corrosion fatigue is a major factor leading to the high strength steel wire deterioration of bridge cables. In this study, accelerated corrosion and fatigue stress were simultaneously applied to high-strength galvanized steel wires using a combination of a fatigue testing machine and an electrochemical workstation. While accelerated corrosion was achieved by galvanostatic polarization, the dissolution progress of galvanized coating layer was monitored using potential-time curves. Metallographic analysis of the galvanized high-strength steel wires for cables was conducted using scanning electron microscopy. The zinc-iron alloy structure within the coating was characterized by energy-dispersive spectroscopy. The relationship between the potential-time curves and the corrosion progression of the coating was established by combining microscopic corrosion morphology. Tafel curves for different steps were derived, and the corrosion kinetic parameters of various zinc-iron alloy phases were analyzed. The fatigue effects on the corrosion of the galvanized coating layer on high-strength steel wires were investigated based on the potential-time curves, considering factors such as the maximum stress, stress range, and loading frequency. The results indicate that under corrosion fatigue, the consumption rate of galvanized coating layer may be more than three times faster than under general corrosion conditions. © 2025 Elsevier Ltd

This paper presents a coupled experimental-numerical study aimed at understanding the mechanical behavior of corroded high-strength steel wires. Accelerated corrosion tests were conducted on steel wires to achieve varying corrosion levels, and the mechanical properties of the corroded wires were characterized by tensile test. The surface morphology of the corroded wires was derived by 3D optical scanning and point cloud models was generated that precisely captured the surface pits. These models were then converted into solid models by surface reconstruction and finite element discretization. Numerical simulations, based on reconstructed surface morphology, effectively predict key mechanical characteristics and align closely with experimental data. The research establishes relationships between statistical pit parameters and macro-mechanical properties, providing valuable insights for predicting the mechanical performance of corroded wires and evaluating the integrity of structures compromised by corrosion. © 2024 Elsevier Ltd

The steel corrosion in Ultra-High Performance Concrete (UHPC) would cause degradation of structural performance or even structural failure. It is an urgent need to monitor and predict the steel corrosion in UHPC, however it is still a tough task. In this paper, Fiber Bragg Grating (FBG) sensors are applied for monitoring the steel corrosion process in UHPC, by combining with steel bar, which is equidistant winding with the sensors, and connected with power supply for accelerating corrosion. The UHPC specimens embedded with steel bars are surrounded by sodium chloride (NaCl) solution, and the steels are artificially corroded with different current densities for investigation. The steel corrosion in Original C60 and Marine Concrete 60 (Marine C60) are applied for comparison. The volume expansion coefficient for monitoring the steel corrosion process, is carried out by FBG sensors, and further comprehensively monitored by three grating sensors. The results suggest that the steel corrosion process in UHPC is slowly with current density lower than 100 μA/cm2, and largely increases with current density higher than 500 μA/cm2, the volume expansion coefficient of corroded steel in UHPC is in range of 2.02–2.62 in this test, which is much different from Original C60 and Marine C60. © 2024 Elsevier Ltd

The bridge of Shanghai Metro Line 10 over Metro Line 6 is a U-shaped concrete single-box double-cell concrete box beam continuous bridge. A novel method is applied to construct the asymmetric cantilever prefabricated and assembled continuous bridge due to the limited construction space and the complex environment. Four mechanical state control methods are applied during the T-shape structure construction process: tensioning pre-stressed steel strand, jacking by the axial force servo system, adjusting the leg reaction force, and setting the auxiliary leg. Auxiliary measures such as the compressive column, side-span counterweight, and temporary pre-stressing are also taken into consideration. The finite element method simulations are performed to measure effects of the four control methods during the construction process. The front leg force of the bridge erection machine and the deflection of the bridge are then monitored. It was deduced that the simulated and measured values of the cantilever T-shape structure are controlled within the limit range during the construction process.

Steel corrosion in concrete is harmful but invisible. Until now, it is still very hard to measure the steel corrosion condition by non-destructive method accurately. In this paper, Fiber Bragg Grating (FBG) sensors include single and three grating sensors, are proposed to bond with steel bar and embed in concrete for monitoring the steel corrosion condition. The steel corrosion condition is evaluated by the corrosion ratio and volume expansion coefficients of steel, which are derived from the wavelength shift of FBG. Bonding materials and bonding ways are investigated in detail for improving the accuracy of FBG sensors. The mechanism of bonding effects on FBG sensor for optimizing the accuracy, has been discussed. The results suggested that the steel corrosion condition is successfully monitored by calculating the corrosion ratio of 2.02–4.24%, and volume expansion coefficient of 2.18–2.65 in this test. The research work is more quantify than the traditional methods for monitoring the steel corrosion condition in concretes. It is helpful for ensuring the safety operation of infrastructures efficiently. © 2023 Elsevier Ltd

The corrosion morphology of artificially galvanized high-strength steel wires and its effect on mechanical behavior was presented. The corrosion morphology was obtained by 3D optical scanner. Four typical pit mor-phologies on corroded wires were identified, namely conical pit, hemispherical pit, combined pit and secondary pit. The probabilistic density function of cross-sectional parameters under different corrosion degree were modeled by normal distribution, and the evolution of model parameters was obtained. Based on the proposed evolution model, the maximum cross-sectional area loss was estimated by '3 sigma rule' of normal distribution function. Subsequently, the effect of corrosion pits on the mechanical behavior of corroded wires was discussed. It shows that the ductility degradation of corroded wires is much greater than that of strength, the ductility degradation is closely related to the ratio of pit depth to residual radius. Besides, it was found that the proba-bilistic density function of the ratio of pit depth to uniform corrosion depth tends to stabilize when the corrosion loss is more than 10%, which indicates that the surface of corroded wire with corrosion pits is uniformly thinning.

The time-varying characteristics of cable modal parameters and cable tensions under good weather and heavy rain are systematically analyzed based on the one-year acceleration and temperature monitoring data of five cables on a long-span cable-stayed bridge. The modal frequency and damping ratio are derived using the fast Fourier transform (FFT) and stochastic random identification (SSI) method. It is found that the cable vibrates greatly under wind and rain conditions. The low-order mode dominates the vibration, and the modal damping ratio has certain differences in the two circumstances. The tension force of each cable throughout the year, derived using the frequency method, is a non-stationary time series and has annual and daily periodic fluctuations. The correlation analysis of the cable tension and temperature shows that the correlation between the two of each cable is different, even differs on the same cable in different temperature ranges. The half-power bandwidth method is used to calculate the damping ratio of each cable for one year, the autocorrelation function and its self-power spectrum are obtained, and the edge probability density distribution function of the damping ratio is also obtained by fitting. The analysis shows that the damping ratio of each cable has the periodic components of 1 day, 12 hours, and 6 hours, and its edge probability density function can be described by Burr distribution. The damping ratio of the cable is less affected by the ambient temperature but more by the vehicle load. © 2022, Editorial Department of Journal of Hunan University. All right reserved.

基于某大跨斜拉桥5根拉索1年的加速度和温度监测数据,系统分析了在良好天气和暴雨天气下拉索模态参数和索力的变化特征.使用快速傅里叶变换和随机子空间法识别模态频率和阻尼比.对比发现,暴雨天气下拉索振幅大,低阶模态的振动明显,模态

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