WALES ASSOCIATION Graduates & Students have heard how innovative engineering transformed the previously derelict Cardiff Bay oval basin into a major public space.
The basin, the entrance pool to Cardiff's first dock, was constructed in 1839. It is now the focus of the Cardiff Bay regeneration scheme, made famous by the Cardiff Bay Barrage (NCE 30 March 2000).
The £4.5M scheme stands as a reminder of Cardiff's great maritime heritage and, according to Arup's Francis Joseph, 'serves as a symbol of the role that civil engineering played in the industrialisation of Britain'.
Joseph told the meeting that stability problems with the original listed masonry dock walls were the major challenge for the Arup/Mowlem Management project team during construction. These were 11m high gravity structures, founded on a timber raft supported by a combination of timber sheet and driven piles.
However, Arup uncovered evidence of failure in the walls just two years after their construction. A report written at the time pointed to bad design and construction which led to almost immediate movement of the masonry wall and failure of the piles at the wall's toe.
Various ideas were considered to overcome the problem, but options such as underpinning or ground anchors were rejected on technical, land ownership and financial grounds, Joseph explained.
The adopted solution involved construction of a reinforced concrete slab to prop the walls. The slab is continuous through the neck of the basin out to the entrance and fans out to form the surface for a boardwalk.