According to an official report, a sinkhole at the Victoria Fountain in Brighton appears to have been caused by a ride at the first Christmas market last year.
But the well – and the Victorian sewers beneath it – do not appear to be at further risk and steps can be taken to spread the burden in the future to prevent a repeat.
The weight of the vehicle, supported by a jack, appears to have damaged a thin surface area that had a gap or void underneath caused by fine soil being washed away by water.
The official report was prepared for Brighton and Hove City Council by civil and structural engineer Jon Orrell, a founding partner of the Hemsley Orrell Partnership (HOP).
Mr Orrell said: “Our observations seen at the surface show that a high load from a jack ‘punched’ through surface strata in an area where a void underneath likely already existed.
“The stress from this jack was far greater locally than any general use would have generated before.
“Provided future exceptional point loads, such as heavy truck wheels or jack stands, are adequately managed with appropriately sized spreaders – and the situation is properly monitored – we believe there is no immediate concern for additional Schwalbe holes to arise.”
The sinkhole at Old Steine Gardens emerged after the end of the Christmas market last December and is unrelated to problems with the Victoria Fountain, which is being temporarily shored up.
The well’s problems were due to corroding studs and “faulty overhead plumbing” — not subsurface voids or other geological problems, according to a full report to councillors.
HOP has been appointed to provide technical advice and management for a £250,000 project to repair and refurbish the Victoria Fountain.
A report to the Council’s Environment, Transport and Sustainability Committee said: “This work is now scheduled to start in 2023, following two unsuccessful attempts to tender for the contract with no tender responses received.
“It is part of HOP’s mandate to assess ground conditions to ensure safe working practices, including the use of a crane required for the well rehabilitation project.
“Against the backdrop of rising construction costs across the country and a lack of expertise and skills in construction, difficulties have arisen in bidding for this project.
“We had two unsuccessful tender attempts. Both were done through the Council’s existing framework agreements and a specific list of contractors recommended by the external structural consultant.
“A total of 12 contractors were invited to bid and no replies were received.
“A third bidding process has been completed and two bidding responses have been received which are currently being analyzed.
“It is intended to appoint the successful contractor at the end of November, with the aim of starting on site in mid-December and completing the rehabilitation project by the end of March.
“However, this is subject to confirmation of costs and funding, with the timeline dependent on weather conditions and the volume of ‘unknowns’ – because until we crane out the upper parts of the structure we won’t know the full extent of the condition and deterioration.” the cast iron construction and mechanical facilities.”
The report was produced in response to a motion by Conservative councilwoman Mary Mears at a full council meeting in February.
It was put up for debate in the Environment, Transport and Sustainability Committee at Hove Town Hall last night but – four hours into the session – was accepted without discussion.
https://www.theargus.co.uk/news/23127970.official-report-sinkhole-victoria-fountain-brighton/?ref=rss Official report of a sinkhole at the Victoria Fountain in Brighton