Strengthening an Existing Berth From 8900 DWT to 35 000 DWT

The 2nd Millennium ended with considerable publicity for major engineering works on TV and in the media. The Dome, the Wheel, earthquake effect on bridges, all received extensive coverage, and engineering topics for once provided widespread after-dinner discussion among non-engineers. Have members discerned a greater general interest as a result of this higher profile for engineering matters?

Dr J. G. M. Wood (F)(Structural Studies & Design Ltd) The complex build-up of the cable-stays with multiple strands in the PE pipes with cement grouting and then wrapping at Houston (Fig 15 in the paper) contrasts with the simple, spiral strand wire ropes traditionally used for cable-stayed bridges and suspension-bridge hangers in the UK. I was involved in the retensioning and replacement of cable-stays on the Wye and Erskine Bridges and the early replacement of hangers on the Severn Bridge. The problems experienced on these bridges included creep of the cables due to bedding-in of the spiral strands necessitating retensioning (e.g. Erskine Bridge sagged by about 750mm because of cable-stay creep). The fatigue problems at the lower socket ends of some of the hangers on the Severn Bridge were associated with high axial stress ranges and secondary bending effects, which can be avoided with more appropriate design and detailing. Similarly, the local socket neck strand corrosion problems experienced can be avoided by improved detailing without the elaboration of wedge anchors and grouting used in the VSL system. Because the socketed hangers were inspectable and replaceable, the problems were picked up early and remedied.

The in situ Concrete Building at Cardington is part of the European Concrete Building Project. This industry led initiative aims to improve the efficiency of production and the performance of concrete buildings to better meet clients' needs for reduced costs, better quality and higher speed'. Dr Paul Chana and Peter Campbell