Design of a Spun Pile Vertical Wall Breakwater for the Improvement of Damaged Cellular-Cofferdam

Abstract

A new breakwater is on demand to replace the function of an existing steel sheet pile cellular-cofferdam at TPPI Tuban Port of East Java. The existing breakwater has been partially damaged due to severe corrosion and hard attack by monsoon waves. An open frame structure of spun pile vertical-wall breakwater is proposed as an alternative design. The spun pile is a pre-stressed concrete hollow cylinder pile with outer diameter 1800mm and thickness of 200mm. The spun pile lengths vary between minimum 28m to maximum 33m according to the position of hard soil against seabed. The new breakwater is designed to stand against 100yrs RP wave with Hs = 4.7m. Wave height variations around the structure are simulated using Boussinesq Wave module of MIKE21 software, while SAP2000 is used to calculate the strength of superstructure to withstand existing loads and certain load combinations. Plaxis software is used mainly to analyze substructure using existing soil data. This article describes the design process of spun pile vertical wall breakwater, started from loads calculation, then define load combinations, analyze structure in SAP2000, analyze structure in Plaxis, determination of specification and dimension, to design drawings creation.