Holdfast Training Services Trial Blog

I thought I would share a near miss that could have ended very badly on my site last week. It is still currently under investigation so this information is as accurate as I have it at the moment but is still a little sensitive.

The demolition of the car park is about 70% complete and we are working approximately only 10-15 metres above street level. At the time of the incident we were on floor 2 demolishing a beam and column on the leading edge of a cantilevered section.

The procedure had been always to break the cantilever from the top completely, clear the rubble and then move the plant backwards a structural bay and start on the main slab. As the slab is much thinner than the beam of the cantilever the machines normally leave the beams until last. A 13t excavator will break the concrete off the beam and then use its arm to bend the rebar downwards so it is not protruding. A worker with a gas cutter will then follow behind and trim this bar.

On this particular day the job was assigned to a new driver who in turn was using an 8t breaker which did not have the power to bend the rebar with its arm. The driver after breaking out the concrete could not bend the bar and instead of waiting for the bar to be bent by someone else just continued the job. He began breaking the top of the concrete column the beam was fixed to. This lead to the loosening of the protruding rebar and eventually it became dislodged and fell from its position, through the scaffolding onto the street below. This photo shows where the rebar fell from the staircase and the pod it hit below

This was 5m of 32mm bar weighing approximately 30kg. It landed on a bathroom pod that was being delivered at the time and skewered it straight through writing the pod off. It goes without saying that had the delivery not been taking place it is just as likely a person could have been stood in the exact position. This is the offending bit of rebar. My foot for scale (size 9)

Conclusion: The machine operative was sacked that day. The method statement has subsequently been re-written now that when attacking columns with cantilever rebar still attached it must be attacked from the bottom and once the concrete is removed the whole column may be bent down by a 13t only. This previously was not done because of the risk of the larger structure falling onto the floor and causing collapse of the slab with the machine still on top. To prevent this the machine must reverse a structural bay back before pulling the beam down. This photo is the new method of leaving some concrete above to keep the rebar secured and then break the bottom of the column.

I have tried my best to explain the procedure but I have attached photos that hopefully paint the picture.

I must say relationships before the incident were of mutual trust and SRM were happy to let the subbie a little slack, since the incident SRM have tightened the lead a little and it is leading to tension on site. The subbie maintain it was a “freak accident” but then why would they sack the operator? SRM monitor and grade their SC on a monthly basis and that goes into a central company tender database – something tells me this subbie may not be selected again.