Lifeboat station and slipway presents piling challenge
Substantial depths of unstable material meant the boathouse piles couldn’t be less than 30m long – far longer than those used on lifeboat facilities built in the past.
The brief for this award winning scheme called for a glulam framed superstructure supported off a concrete undercroft, to be built on tubular piles. The central area of the existing pier head deck had to be cut away to accommodate the footprint of the new facility, and the remaining dilapidated pier head deck refurbished.
Consultation on the Swansea Bay Regeneration plan favoured a visitor’s ‘point of arrival’ and weather shelter building on the listed cast iron pier head. Though this was a more expensive option than building a slipway lifeboat station alongside the existing pier – built in 1898 – the client chose to accommodate the visitor’s facility within the new RNLI station, as preferred by the Planning Authority and pier owner.
The boathouse was located within the pier head in view of the ground conditions for the slipway piles and the proximity of deep water for launching. It also maintained an uninterrupted view around the bay from the pierhead, which was preferred by the planning authority.
Geotechnical works included the piled foundation for the boathouse suspended over the pierhead and the piled foundation for the slipway seaward of the pierhead itself.
Below the large tidal range, the ground conditions consisted of 8metres of mud over 7metres of stiff clay, lying on a layer of mudstone bed rock.
The substantial depths of unstable material meant the 1200 diameter boathouse piles couldn’t be any less than 30metres long – far longer than those used on similar lifeboat facilities built in the past.
The scheme has won several industry awards, including:
- The Institution of Civil Engineers South East England Awards 2015 “Designed in the South East”
- GOLD award for Built Environment & Architectural Heritage at the Green Apple Awards 2015.