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This study presents an experimental investigation on the combined effect of mechanical loads and corrosion using the designed polytetrafluoroethylene tube-packaged fiber Bragg grating (FBG) sensors, as to implement long-gauge FBG (LFBG) sensors in corrosion detection practices for structural health monitoring. A simplified LFBG-based sensing model was proposed for strain measurement in terms of the Bragg wavelength change. Correspondingly, a systematic corrosion assessment strategy was developed to estimate corrosion severity and average corrosion rate. Upon this, the experimental study was performed on epoxy-coated steel specimens embedded with LFBG sensors, where the loading, corrosion, and combined loading–corrosion tests were used to explore the effect of mechanical loads on corrosion behavior. Test results revealed that the specimens subjected to combined conditions exhibited more severe corrosion damage. The maximum mass loss was observed to be 1.82 and 2.43 in percentage under individual corrosion and combined loading–corrosion conditions, respectively. Also, the pit depth under combined conditions was found to develop rapidly in the early stage. The pit depth severity ratio was around 0.2–0.8 during the 67 days of exposure, indicating an evident impact of loading on corrosion severity. Furthermore, the maximum average corrosion rate under combined conditions was found to be 5.66 times that under individual corrosion conditions.

Each year, the global cost that is accounted to corrosion was estimated at $2.5 trillion. Corrosion not only imposes an economic burden, when corroded structures are under various loading conditions, it may also lead to structurally brittle failure, posing a potential threat to structural reliability and service safety. Although considerable studies investigated the combined effect of external loads and structural steel corrosion, many of the current findings on synergetic interaction between stress and corrosion are contrary. In this study, the combined effects of dynamic mechanical loads and corrosion on epoxy coated steel are investigated using the distributed fiber optic sensors based on optical frequency domain reflectometry. Experimental studies were performed using the serpentine-arranged distributed fiber optic strain sensors embedded inside the epoxy with three different scenarios including the impact loading-only, corrosion-only, and combined impact loading-corrosion tests. Test results demonstrated that the distributed fiber optic sensors can locate and detect the corrosion processing paths by measuring the induced strain changes. The combined impact loading-corrosion condition showed significantly accelerated corrosion progression caused by mechanical loads, indicating the significant interaction between dynamic mechanical loading and corrosion on epoxy coated steel.

The effects of uncertainty due to the variability of soil properties, pore pressure, and earthquake forces on the stability of a deposit slope in the hydropower reservoir are investigated. The spatial variability of soil properties is incorporated in the probabilistic slope stability analysis by a random field model, and a sensitivity analysis is conducted considering spatial variability of soil properties. Cutting the slope can reduce the risk of slope failure, which has been corroborated by the probabilistic slope stability analysis. The sensitivity analysis shows that additional measures such as drainage and toe protection can help stabilize the slope before reservoir filling.

Controlling construction speed is a key factor to ensure the stability of dam slope in soft groundsill. In this paper, for the construction of soft groundsill damming in Shuangwangcheng reservoir, a dynamic monitoring method of soft groundsill damming, considering the excess hydrostatic pore water pressure and anti-slide stability safety surplus degree of dam slope during the construction, was proposed. First, the real-time excess hydrostatic pore water pressure in soft soil layer during the construction was obtained by monitoring. Second, the real-time stability safety factors of dam slope during the construction was obtained by analyzing the stability of dam slope. Finally, according to the stress levels of excess hydrostatic pore water pressure and stability safety factors of dam slope during the construction, different monitoring and early-warning threshold values were set, then the construction safety level was evaluated and different monitoring control predetermined plan were employed to take different engineering measures to ensure the safety of dam. This method can ensure the stability of the dam foundation and improve construction efficiency, shorten the construction period and save the project cost.