BIRLING ROAD BRIDGE COLLAPSE
Birling Road is a country lane that crosses the M20 just west of Junction 4, the A228. It was one of the first single span overbridges in the country, with no central pier, and it was curved and cambered. It was scheduled as a 24 hour pour just before the new hours law came in restricting driving to 8 hours. There was much hurried re calculation, with the pour now scheduled for 18 hours supplied by ARC's 3 plants at Borough Green, Allington and Rochester.
On a bridge pour like this there is normally a scaffolding crew tightening the falsework the whole time, because of the vibrators working on the deck. Nobody thought that the faster pour needed more tightening. Add to that the gap in the falsework to allow motor-scrapers to keep working, and that this whole area was below the water table, and therefore a tad unstable.
The pour was 800 metres, and all went well until the last couple of loads, when the entire centre section collapsed, killing one lad and seriously injuring another.