Discussion. The New Dry Dock at Belfast.

Abstract

There may be some people who think that there has been duplication of effort in providing two large docks at Belfast for the shipbuilding industry. While the new building dock provides for the float out of the near finished product, the dry dock is primarily designed for the ship repair side of the industry and for those ships still launched by conventional means at the Musgrave Shipyard.130. When the new workshops are in full production four tankers of the 300 000 ton class will be built in the dock each year as well as two bulk carriers of the 100 000 ton class at the Musgrave Shipyard.131. The throughput of the building dock will be such that it will not be possible to use the dock for ship repair work.132. The sill level is such that there is a restriction on deep draughted vessels from entering the dock. There is 8.38 m of water over the sill at MHWS at the building dock compared with 11.6 m at the dry dock. M r RennieSix contractors were invited to submit tenders and my firm was fortunate in being awarded the Contract-this expression of confidence by the Belfast Harbour Commissioners was particularly welcome to Charles Brand, who were building quays in Belfast Harbour for the Commissioners in the mid-1800s.134. It was a personal pleasure to me as I had been working closely with the General Manager and the Chief Engineer and his staff on numerous contracts in the Belfast Harbour for very many years, and I was also renewing an old association with the Consultants, Rendel Palmer and Tritton. M r J. A. Williams, Wilton and BellFigure 2 impresses me as being an extremely satisfactory design for a dry dock and one which takes full account of the practical construction problems and methods. With regard to the anchor piles, was the use of stressed anchors to be taken down into the rock considered in the design? I think this might have been more positive and cheaper.136. The job was designed in the early 1960s. If it were being repeated in 1972 would diaphragm walling be preferable to sheet piling, either technically and/or from the point of view of cost?137. In Fig. 2, there is a gap between the bottom of the bearing piles and the rock.Does this mean anything, or were the piles carried down to the rock? Was there any trouble with boulders among the other pile driving problems? 138. I have experience of Peine piles in countries outside the UK and think they are extremely useful from the design aspect. On one occasion in difficult ground half-inch jetting pipes were introduced into the leading interlocks to assist the driving.139. Referring to 5 18, is it wise to take adhesion into account in resisting uplift?In similar designs I have always ignored this adhesion in order to keep something in hand. If there is risk of flotation, there is a chance of lubrication between the clay and the piles, and the use of adhesion in design appears doubtful. What proportion of the overall factor of safety is contributed by the adhesion?140. Is there any positive anchorage between the concrete floor and the piling in the form of sh...