Large waves pose a significant threat to the safety of low-laying coastal bridges. In 2004 and 2005, many coastal bridges were destroyed by the large waves generated by Hurricane Ivan and Katrina. A series of studies have been conducted to investigate the wave action on bridge decks. However, the effect of seabed topography on wave forces is seldom considered. In this study, a numerical model of wave impact on bridge decks located close to a sloping seabed was set up based on OpenFOAM-v1912. The reliability of the present numerical model was checked against published experimental results. The wave forces acting on the bridge decks located before and after the sloping seabed were compared with a bridge deck located above a flat bottom. With the validated numerical model, the effect of the wave properties, coefficient of submergence, and the inclination on wave forces were investigated. The results show that the wave forces on the bridge are affected by the interaction among the incident and reflected waves, the position of the bridge relative to the sloping seabed, and the inclination. These findings emphasize the complex dynamic effects of wave forces on bridges and the importance of considering seabed topography in bridge design and strengthening strategies. This research contributes to an improvement in the safety of coastal bridges, especially in the face of increasing threats from climate change and sea level rise, as well as promotes the development of more resilient infrastructures.

Chloride ion penetration frequently leads to steel corrosion and reduces the durability of reinforced concrete. Although previous studies have investigated the chloride ion permeability of some fiber concrete, the chloride ion permeability of the basalt fiber reinforced concrete (BFRC) has not been widely investigated. Considering that BFRC may be subjected to various exposure environments, this paper focused on exploring the chloride ion permeability of BFRC under the coupling effect of elevated temperatures and compression. Results demonstrated that the chloride ion content in concrete increased linearly with temperature. After exposure to different elevated temperatures, the chloride ion content in BFRC varied greatly with increasing stress. The compressive stress ratio threshold for the chloride ion penetration was measured. A calculation model of BFRC chloride ion diffusion coefficient under the coupling effect of elevated temperatures and mechanical damage (loading test) was proposed.

The durability of subsea tunnels under the coupled action of stress and chloride ions was analyzed to estimate the service life and provide a theoretical foundation for durability design. The influence coefficient of the stress on chloride ion transmission at lower stress levels was discussed according to the material mechanics, and was verified by experimental data. A stress calculation model of a subsea tunnel’s lining section is proposed based on the plane-section assumption. Considering the space-time effect of the convection velocity, a partial differential equation was constructed to calculate the chloride ion transfer condition under the coupled action of stress-convection-diffusion. The numerical solution of the partial differential equation was solved and the sensitivity of the parameters was analyzed. The subsea tunnel’s time-varying reliability index was calculated following the Monte Carlo method, and was used to predict the service life. The results show that the chloride ion concentration calculated by considering the coupled action is larger and the reliability index is lower than calculated only considering diffusion. Our findings contribute to the conclusion that durability designs of subsea tunnels should consider the coupled action of stress-convection-diffusion. An effective method to improve the service life of a subsea tunnel is to reduce the water–binder ratio or increase the thickness of protective cover.

Slopes suffer damage from waves in coastal environments. Precast blocks with well-designed geometrical characteristics can benefit the construction of revetments by mitigating the issue of wave overtopping and dissipating wave energy. In this study, we numerically studied the effect of the geometrical characteristics of precast blocks on wave overtopping by carrying out a numerical simulation of wave overtopping on a slope covered with precast blocks. A total of three different types of blocks were considered in this study to determine the optimal geometric shape using a validated numerical model. Our numerical investigation demonstrated that the roughness of the precast block plays an important role in lessening the height of the wave run-up. Concave and embedded regular hexagons could reduce the wave run-up height by 44.6% compared with smooth slopes within a 2 s wave period. Herein, we evaluate and discuss the influence of the geometrical characteristics of a given precast block, such as thickness, aperture, and wave dissipation notch, on wave run-up. We also present an empirical formula for predicting wave run-up on a slope covered by a concave and embedded regular hexagon-type prefabricated block. This study provides valuable insights into the design of prefabricated revetment blocks.