Investigation of random wave impact on highly pervious pipe breakwaters

• Reduction of wave impact force with highly pervious pipe breakwaters is investigated.
• Impact forces showed a strong relationship with the shielding rate and the porosity.
• Screen breakwaters could effectively mitigate the wave impact forces.
• Maximum percentage of impact force reductions was over 95%.
• Screen pipe breakwater could effectively reduce the impact wave pressure.

The main cause of damage to offshore structures is the wave impact force. Protective structures such as submerged breakwaters, screen breakwaters, and various piles are often designed to provide additional attenuation (reduction) of the impact force. In this study, reduction of the wave impact force and wave pressure on an embankment with highly pervious pipe breakwaters is investigated through physical experiment. The process of wave impact is rather complicated, involving strongly nonlinear and transient effects. Coastal structures are often partially damaged by the strong intensity of the wave impact force; therefore, the effect of the wave impact force is one of the important factors to be considered for the safety and/or destruction of coastal structures. This study addresses the use of highly pervious dense pipes with small apertures, which can be beneficial for convection and interchange of seawater within the harbor district and, furthermore, perform wave absorption effectively. This study investigated the performance of a pervious pipe screen breakwater installed in front of a seawall in terms of reducing the wave impact force and wave pressure. The physical experiments were performed by considering regular and irregular waves under various conditions. The experimental results indicated that pervious pipe obstacles placed vertically in front of an embankment can effectively mitigate and reduce the wave impact forces by over 70%.