Rebar Near Miss
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.
Holdfast Training Services Trial Blog 
I think I get your explanation, either way lucky to hear noone was hurt. It sounds like it was a accumulation of issues. What was the intended role of the 8T breaker i.e. why was it there if it isn’t man enough? Was specific plant not specified in the MS? I trust he’d signed saying he’d received an MS brief?
There is a range of plant on the roof. Mainly because the 13t machines can’t sit near each other due to the capacity of the slab. When the parapet is removed for example two machines need to sit adjacent (one to hold the parapet in suspension and the other to break the toe). This wouldn’t be possible for two 13t machines.
I’m always very suspicious when an operative is instantly dismissed. It necessarily prevents their side of events from being understood and therefore the true sequence of events and rationale from being established. Consider the scenario: “A new operative arrived on site and pointed but several high risk flaws in the companies method statements and suggested there was too much luck in things having gone OK so far. He was told to just get on with it or lose his job. He was then given a lighter piece of plant to operate as a churlish rebuke for being a pain and everyone knew the vibration and stress on the body meant he would have aa sh*tty day as a result. so, having pointed out the issues he got on with the job but when he reached the point he couldn’t bend bars and could see an evident risk becoming and issue he suggested he stop until it could be made safer. He was told to JFDI or get out and don’t expect pay for today. He got on with it and the risk became a issue and bar fell from height with only luck again saving greater disaster. The management knew they had created the whole situation and should be subject to HSE investigation and heavy penalties so immediately sacked the ‘renegade ‘ operator and conducted and internal investigation.” If only this sort of event was investigated with the same rigor that would be applied if the story had been “expectant mother skewered and killed by demolition contractor whilst standing on public footway” perhaps we would hear fewer of these tales.
I trust this has been reported to the HSE as a near miss with potential to have caused injury or death to a member of the general public outside the secured site boundary?
It has been reported to the HSE and the operator did have a statement taken from him. Up to now I don’t know the full intricacies of the investigation as it is still pretty fresh.
I don’t believe the hypothetical situation is fully likely however I take your point making the operator redundant does look awfully like sweeping something under the carpet. I think maybe at least one of those situations you described did happen and the S/C are protecting themselves.
I’ll comment back on this post at a later date if I’m still here when something comes back.