Dolphin Mooring Structure Assessment PT. Smelting Gresik Due to Being Hit by a Mud Barge as a Basis for Repairing Structural Elements

Abstract

A wharf or harbor is a complex of buildings connecting land and sea which functions as a place for mooring or docking of ships that will carry out the loading and unloading of goods or the boarding and falling of people (passengers) to and from the ship. Because the structure of the wharf is in the sea, incidents can occur either due to natural or human error. One of the incidents occurred at the mooring dolphin owned by PT. Smelting which was hit by a Mud Barge resulting in some damage to the structure. The case study taken is the Assessment activity on the Dolphin Mooring Structure owned by PT. Smelting. The assessment started by conducting a visual survey and the results showed that the damage occurred in the form of spalling and cracks in the concrete elements and also the peeling of the coating layer on the SPP. Furthermore, conducting tests in the field in the form of a UPV test and the results obtained that the density classification of the concrete is in a fairly good condition and the depth of the cracks that occur is still less than the minimum cover thickness. After that, under water testing was also carried out in the form of Thickness test and PIT, each of which resulted in the condition of the SPP pole still being in Fairly Good condition. And the last is destructive testing which is then used as a compressive test sample and the result is that the quality of the existing concrete still meets the quality limits for fc' 30 MPa according to SNI 6880-2016 code 1.5.6.2. Based on the tests that have been carried out, the Mooring structure is still able to function as it should, with some repairs to the damaged structures. For structures that are damaged by cracks, the suggestion for improvement that needs to be done is to inject using epoxy and for structures that are damaged by cracking & spalling, the suggestion for repairs that needs to be done is to do injection using grouting. Whereas in the SPP pole structure, the suggestion for improvement that needs to be done is to restore the initial layer consisting of HDPE and FRP Wrap. The Catwalk structure did not suffer any damage, it's just that the placement part failed due to corrosion and needed to be renewed. Based on several suggestions for improvements that need to be made, it can be estimated that the time for carrying out the work is 2 months or 60 calendar days.