A 'MAJOR catastrophe' at one of the UK's 4,000 multistorey car parks is imminent unless urgent action is taken to review design codes covering edge barriers, a leading structural expert claimed this week.
The warning, from Southampton University senior lecturer Dr Colin Jolly, came the day after a car smashed through an edge barrier of a Kent car park - for the second time in two years.
Jolly condemned current codes as inadequate and said 'a major catastrophe' caused by edge barrier failure was long overdue.
He explained: 'I have tested current designs in my laboratory and many have failed the code criteria. There is no specified proof test for edge barriers, and many car parks use standard motorway crash barrier designs that were never intended for edge barrier applications. A statistical analysis shows we are having fewer accidents than can be expected - and the next one could involve multiple fatalities.'
Two people were slightly injured this week when their car fell 4m from the first floor of Rose Lane car park in Canterbury. The accident happened despite £250,000 being spent recently on barrier strengthening and replacement in the aftermath of the similar accident almost exactly two years ago.
A police spokesman said the car had been descending the exit ramp at around 1pm on Monday when it apparently failed to make a turn and went straight on through the barrier.
Operator Canterbury City Council immediately closed the car park and called in specialist consultant Brian Pyle Associates to carry out an investigation. A CCC spokesman said that both the strengthened and new barriers 'complied with the latest national standards'.
The spokesman said the car park would remain closed until the consultant had reported back. He added: 'The car appears to have been travelling at some speed, but until the police have completed their investigation we have no idea exactly at what speed it hit the barrier.'
The Standing Committee on Structural Safety has been warning of potential multistorey car park disasters since 1994. Its campaign for new design guides was boosted by the earlier incident at Rose Lane in 1996.
In the 1996 incident an elderly driver was seriously injured when his Volvo went through the edge barrier on the car parking area proper (NCE 18 January 1996). The barrier's base plates pulled away from the holding down bolts under the impact, allowing the car to topple from the slab and land upside down in the road below.
However, revision of the key IStructE design guide has still not begun, apparently because of a lack of government funding for the work.
Replacement barriers installed at Rose Lane were all designed to comply with BS 6999: Part 1: 1996, according to a spokesman for Berry Services, the supplier. This is the loading code for buildings, and it requires edge barriers for most multi-storey car parks to resist the impact of a 1,500kg vehicle travelling at 4.5m/sec (16.2km/h). At the end of straight downward ramps over 20m long this design load is doubled.
But SCOSS secretary Dr John Menzies said he was not convinced these criteria 'were appropriate', and he renewed his call for the Institutions of Civil and Structural Engineers to prepare new design guides for multi- storey car parks 'as a matter of urgency.'