The need for good knowledge of the construction of old waterfront walls and a coordinated approach between stakeholders has been highlighted by new guidance published by construction standards organisation Ciria.
The new C746 Old Waterfront Walls document in an update of a 1992 document which adds experience gained in recent years following high profile waterfront wall failures at Bridgwater and Dawlish.
“A significant amount of research into the different types of structures that exist in the UK went into the previous document and the new guidance builds on that with a focus on risk management and legislative changes,” said HR Wallingford technical director Stephen Cork, who was the lead author on C746.
“There was a need to update the guidance to cover roles and responsibilities of ownership, third party impacts and to add information about use of modern surveying and repair techniques.”
Speakers at the guidance launch event last week said highlighted that assessment of old waterfront wall structures is a “black art” as they are not designed to modern standards so it is difficult to assess capacity and stability using such standards.
The guidance uses the sea wall collapse in Dawlish in February 2014 as an example of the issues regarding responsibility. “This was one of the more complicated examples,” said Cork. “The guidance outlines the health and safety, transport, coastal protection and environmental laws that must be considered when looking at an old waterfront wall structure. The document also outlines maintenance issues and the need for emergency planning and procedures to be in place should a failure occur.”
Environment Agency area coastal engineer Nick Ely, who spoke about the challenges of structures without a defined owner in a failure situation, said that it was often “who blinks first” as to who takes the lead in managing an emergency situation.
Arup associate Steve Hold used examples of historic structures in Jersey to highlight the benefits of modern surveying techniques such as Lidar and drone footage in order to identify issues before failure occurs.