DefinePK

Abstract

Man took a step to protect the seashore using seawall or revetment as one of the concerns towards the condition of the seashore, but many shore protectors like seawall and revetment had been found broken. Its erosion affects the feet of the construction. One of damages caused by that is the high run-up and run-down when the wave attacks at revetment wall. So it is necessary to find a method that can reduce the result of run-up and run-down at the building structure, create an enhancement of the structure that is safe from the wave attack with the height of the structure, and also increase the cost. Run-up and run-down can be reduced in so many ways, such as the increased height of the structure; the wall can be made from rough material or to reduce the wave energy that can be obtained by having the wall with perforated block. Perforated breakwater is an alternative to reduce the wave energy and the idea of making this seawall or revetment made from porous block will be a solution to handle run-up at the seashore to protect the building structure and the hole of the porous concrete block will reduce concrete use and could be a proliferating place for marine biota. The purpose of this research is to investigate the performance of a perforated breakwater which is made of concrete block in order to reduce the run-up and run-down. A research with 2D physical modeling is conducted in the Coastal Engineering Laboratory of Hasanuddin University. Three different types of perforated concrete block that have the different diameter and porosity which are simulated with the different height, period, and water depth (H, T, and d). The parameter dimension of the models is using a geometric scale of 1:20. The result of the research shows that the parameter of the armor model which is represented by the model length (B), porosity (ζ), Irribaren number (Ir) and the wave steepness (Hi/L) is quite influential towards the reduction of Ru and Rd. As the model gets longer and the porosity values of the block gets bigger, then the bigger the reduction of Ru is. The relationship between Ru and Rd with IrK is presented in the form of a relationship of dimensionless parameter, where K is a function from ζ, B/L, and Hi/L. Therefore, the empirical equation that has been derived could be used to plan a prototype system for the coastal protection with perforated concrete block.