Top Errors of the week No2
So we have finished digging and have started to build back up. I have moved to the Contract Admin department to focus on getting a bit of commercial experience and prep for the removal of the temporary supports.
In the last week we have finished of Basement 6 and have poured three quarters of Basement 5. The productivity has really got to some people and we have had a number of safety incidents this week. I have had to adjust this as I have just heard of another classic.
In 5th place is the site supervisor who poured 100 MPa concrete into a 50 MPa column, failed to puddle poured a 20 MPa slab, and then continued to pour a 100 MPa column on top. We now have a 20 MPa weak spot in an otherwise overly stiff column.
In 4th place is the guy who electricuted himself while drilling in a puddle. He is ok but, the site was shut down for 2 hrs.
3rd place goes to the guy who brought his own cutter on site which had some of the wires exposed resulting him getting a shock. He too is ok but, another loss of 2 hrs.
2nd place goes to the guy cutting rebar next to a spray can and the sparks caused the spray can to explode – no injuries but site shut down for two hours.
This week’s top pick though has to be the idiot who cut holes in my ground anchor walers to get his falsework in. The designers are after welding steel plate back on but, this will delay our programme. So this is now an issue. When I was inspecting the damage one of the formworkers then told me it was shocking that they hadn’t cut off more! Looks like it is time to bust some calcs.
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![IMG_4595[1].JPG](https://pewpetblog.com/wp-content/uploads/2016/09/img_45951.jpg?w=595)
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Your top pick is all up gittish; Not only was there…”well it’s only a massive bit of steel – can’t be ding thing useful” BUT, from your photo at least, it looks like it would have been easier to birdsmouth the timber than to cut the steel…….All in all a worthy set of entrants for the Darwin award
I had a conversation with the formwork leading hand. He tore his guys a new one. It just wasn’t necessary. I’ve managed to sort it but it is now a risk that didn’t need to be there. The good news is I think this piece was over designed to deal with the neighbouring buildings piles s and we haven’t seen anything like the load. Fingers crossed until Tuesday.
One thing that really strikes me about your site is that it appears 10 or 15 years behind techniques used in the UK.
You do not appear to use much proprietary for work systems?
All looks a bit old school to me?
That is probably fair, the systems are available her but, there are some challenges to using them. We also have a tight budget and a PM with pour judgement. I think once we get above ground and hit PT you will see more modern techniques. At the moment we are using ordinary RC and the whalers are pretty restrictive.
Have you not recently cast a slab a metre or two below your whalers which will now be taking on a large part of the role of your ground anchors anyway? Don’t they all get removed at some point what the slabs go in? Just wondered.
I suspect the 20MPa slab will be significantly more than 20 MPa and, because it is fully constrained, there is an interesting design work around – think triaxial testing…
Hi Richard, the slab below is replacing the ground. You are correct they are all to be removed but the walers are designed to be built over. If this waler were to be removed it would have to span from the slab to the next waler about 6.5 m. Which is beyond the capacity of the embedded secant pile wall.
The slab will be more than 20 MPa (hitting 28 MPa at 3 days and 45 MPa at 28 days). I think the issue is the span in the wall though. Luckily we got the slab above in 2 days later. We are moving so fast now, well until we hit the props in 2 weeks time and I get massively found out.