Evaluation of Existing Coal Unloading Jetty Capacity Due to Increased Coal Vessel Size for Pacitan Coal Fired-Steam Power Plant

Abstract

In 2018, the breakwater at Sudimoro Coal Fired-Steam Power Plant (CFSPP) was severely damaged, allowing wave directly penetrate inside the harbor basin area. The harbor and coal unloading jetty structure of the CFSPP was designed to serve 27,000 Dead Weight Tonnage (DWT) dry bulk carriers, with maximum allowed wave height of 1.0 m. However, due to the breakwater damage, the wave height inside the harbor basin area, has increased to 1.5-2.0 m. It may risk the vessel and jetty structure during the berthing and unloading process as the vessel motions were larger than allowed in the initial design. To address this issue, increasing the vessel's capacity to 40,000 DWT was considered, with the expectation that the larger vessel would withstand higher waves. Vessel size increasement have to be evaluated against the existing harbor infrastructures, such as the capacity of existing coal unloading jetty structure, turning basin radius and depth. This study aims to evaluate the feasibility of the existing harbor jetty and harbor basin at the Sudimoro CFSPP to accomodate larger vessels. Bollards and fenders upgrades were required. However, the major key is in the existing pile capacity of the existing coal unloading jetty structure, as the results indicate that the current pile capacity of coal unloading jetty structure cannot support the 680,1484-ton axial load from a 40,000 DWT ship, as it exceeds the allowable bearing capacity.