ABSTRACT
During the construction phase of Berth 5, sea bed conditions were found to be significantly different from the initial geotechnical study. Re-analysis of the sheet piles showed that the underwater sheet pile wall had the potential to fail during the dredging operation. This in turn could have caused the deck to collapse into the sea. A restraining system was developed that allowed dredging to continue without the risk of the underwater sheet pile wall collapsing. The restraining system was innovative and allowed for the steelwork to be floated into position and then reused six times. Loading restrictions on the deck and the fact that the deck cantilevered over and beyond the underwater sheet pile wall prevented the use of mobile cranes. This paper describes the design philosophy, construction and setup of the restraining system. It furthermore provides some guidance for similar types of work, through lesson learnt on the project.
