Evaluating design formulas of berm breakwater by means of physical modeling and in situ surveying: case study of Shahid Beheshti breakwater

Shahid Beheshti Port is located at the inner side of the south eastern Headland of Chabahar Bay. Development is planned to be completed in two separated phases. As the first part of portdevelopment project, existing breakwater shall be further extended about 1650m. Although this length would be sufficient for the next development phase, based on the breakwater design criteria, allowable overtopping discharge, is different for these two phases. So crown wall shallbe applied in the second phase of breakwater development for limiting the overtopping discharge. Since the quarry material is available in the vicinity of project area, the rubble mound breakwater with armor stone has been designed for the extension parts. Considering the highdesign waves, the conventional breakwater needs large heavy rocks. However the extraction, transportation and handling of rock is limited to access to quarry with appropriate quality of rockin the vicinity of project location and also availability of equipments with enough capacity. Therefore, with considering these limitations, Berm Breakwater has been selected as the best alternative. This type of breakwater has been allowed to be reshaped statically or dynamically and its dimensions are a function of acceptable extends of recession area. Although differentformulas have been proposed for determining the profile of reshaping, implementing them for the understudy breakwater with specific materials and hydrodynamic conditions might deal tounreliable results. In this project for verifying the design formula, 2D physical modeling tests have been implemented to ensure the structure workability under environmental condition. Presently 3D modeling is going to be performed. In addition to evaluation the stability ofbreakwater and determining the recession profile, overtopping discharge has been also measured and it is compared with available design formulas. It shall be noted that the existing breakwater is also berm type breakwater and has been built with similar material. So it would be possible tomonitor the reshaped profiles under wave events that occurred the years after construction of breakwater. To sum up, three different sources are available to be compared and the best one can be judged here: Values by design formulas, surveying the recession of existing breakwater and performed physical modeling tests. In this paper, these methods and their results are presented.

Keywords:

Berm breakwater , Physical modeling , Recession , Armor Stability , Overtopping