Skidding and launch of a road bridge, UK
Emanuel School, Battersea, required a new access road and the only option was to launch a bridge from the nearby B234 road over the adjacent four rail lines and into the school grounds. ALE undertook launching of the road bridge using skidding techniques over the four track railway near Clapham junction in London, UK.
ALE carried out detailed design sequencing to ensure that the works could be conducted in the restricted space on site and that, once launched, the bridge would land on the newly formed embankment.
The initial phase was to supply support stools for the bridge build. Once the bridge was erected, additional ALE beams were attached to the launch nose and tail nose. These beams were utilised to jack-up the bridge and jack it down before and after completion of the launch phase.
The skidding equipment and climbing jacks were then mobilised to site, where the jacking equipment was positioned under the bridge and the bridge was jacked-up to a height which allowed the skidding equipment to be installed. A small push-along crane and pallet truck were utilised under the bridge to move the jacking and skidding equipment into place.
A second set of skidding equipment was set up on the far side of the embankment; this skidding equipment supported the launch nose as it landed. Once all of the skidding equipment had been set up under the bridge, the bridge was lowered down onto the skidshoes and a test slide was carried out as per Network Rail’s procedures.
The bridge was launched within a four hour window during a night-time possession. The launch nose was landed onto the skid equipment on the far side and pushed as far as the track would allow. A piece of the launch nose was removed and both sets of skidshoes repositioned ready for the next part of the slide. The skidshoes were repositioned several times as the bridge supports could not exceed a set distance due to the B234 carriageway remaining open for the majority of the works.
Once the bridge was over its final location, the climbing jacks were positioned under the beams on the launch nose and tail nose. The bridge was then lifted to allow the skidding equipment to be removed and, once clear, the bridge was set down into its final position.