Dover Berth 6, underwater wire concrete sawing, diving, jack-up barge, JUP, marine civil engineering,

DOVER ED6

OVERVIEW

OVERVIEW

Knights Brown approached Topbond to manage and deliver a controlled demolition project in the Eastern Docks of Port of Dover as part of a modification scheme to rejuvenate Eastern Dolphin 6 and allow the berthing of a larger ship. The works required the removal of a triangular section of concrete 13.7m tall x 2.4m long x 1.73m deep, approximately 80 tonnes of concrete.

THE CHALLENGE

This concrete was to be removed in a controlled manner so as not to damage the remaining concrete. Removing the 80 tonnes of concrete was achieved by diamond drilling and wire sawing the section into eight manageable sections of 9 tonnes. Each section had six threaded rods, in three pairs, drilled and chemically fixed into it which had lifting plates bolted to them, meaning that when each section was cut free, it could be craned out. The technical part of the scheme was the demolition works that were below the mean low water spring.

THE SOLUTION

To enable drilling and wire sawing at this depth, an aluminium guide frame was fabricated that the diamond drilling rig and wire sawing pulleys could be fixed to. Topbond employed a diving subcontractor to fasten the guide frame to the uneven and inconsistent wall below MLWS and operate the drilling rig to finish the works. Various underwater obstructions that were not previously identified in the pre-condition survey were discovered by the dive team, meaning a constant line of communication with Knights Brown was required in order to find the best solution and overcome these issues.