When QC falls down
The final pour of the HQ’s Area F for slab on grade happened today…actually it was supposed to be tomorrow! The concrete subcontractors took it upon themselves to pour the slab – in my view so that they could rush off site finally and start another project down south. I’m yet to get to the bottom of what exactly happened, but as I was about to start to look over the rebar I found the concrete pump vehicle parking up next to me and the concrete crew moving to my area from their last slab pour. Having not seen anyone, I presumed all must have been in place with regards to checks and that maybe I had just missed a beat. Nevertheless, I continued to check over the steel as the pour started and started to find problem after problem. What then ensued was one of those awkward situtions where the USACE QA guy with the funny accent had to step in and stop 10 grizzly concretors and cause a back up of several concrete trucks. Clearly the commotion and grumbling resulted in the QC manager and various Walsh engineers rushing out to see what was going on. It then turned into a mess of fresh concrete being dug out, formwork being replaced, and concretors swearing at each other trying to rectify errors I kept raising – Joe, I can sympathise! Problems, to name but a few, were as simple as:
1. Top rebar not being tied down.
2. Top and bottom rebar having clearance from formwork as little as 1cm (should be 2” = 5cm)
3. Laps not being tied together.
4. Rebar seats having been crushed causing a spacing of, at worse, 2cm between top and bottom rebar (slab thickness – 25cm)
Thoughts….
– Only one external QC guy is employed to QC all concrete, cementitious material and rebar across the whole site. He believed the pour was happening tomorrow and intended to check the rebar this morning with me; this meant that when the concrete trucks turned up, he couldn’t check over the steel and was pulled away to do slump checks on the incoming concrete. To add to his confusion he was trying to QC the grout being used for masonry. It is clear to see that QC is starting to slip off the agenda as contractors rush to make up time, and QC is not a deciding factor when scheduling works that overlap – IT SHOULD BE! QC employment and scheduling needs to be thought through cleverly – many a day he has nothing to do, and is there purely because contractually he has to be. This is crazy and I feel his presence is starting to become a box ticking exercise!
– I read an interesting article about ‘QC and continuous education: providing tools for contractors to make ethical decisions’ – BLUF how HR depts need to employ QC workers by personality type, by using tests such as Myers-Briggs in the interview phase, to ensure that QC workers are capable of making ethical decisions. Today was case in point – Walsh’s QC manager told me he had walked the rebar this morning (he was clearly aware that the pour was happening); that was before I then showed him the errors. Hoping he would then rectify the problemsand relieve me by directing the concrete sub-contrators, he limply tried to stop the concretors pouring concrete but then just shrugged his shoulders when they couldn’t hear him…I then had to wade in again. In addition, the external QC checker should have had the balls to raise the issue straight away to the QC manager; if I hadn’t have turned up, the pour would have just carried on!
Never a dull day…
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Nice one. I’m not sure how the QC inspector can have been called to inspect concrete if there wasn’t any due to be arriving until the next day and then said he didn’t know it was to be poured. Sounds like an “I was going to just let it slip by because I didn’t have the balls to stop it and I know the only record you will check after the event are the concrete properties”. In UK you woul need an inspection sign off before pouring or you would be asked to justify/prove good or break out depending upon criticality. ROH/SC-J might have views?
Howard, I love the fact that sub-contractors appear exactly the same regardless of what side of the pond they work on!
Part of my wall got poured on Saturday (not my shift) so one of the other engineers covered it for me. Almost exactly the same incident happened. The concreting foreman was up on the silo roof pouring one of the roof slab sections and as they had finished slightly ahead of schedule he decided to divert the final lorry load to the wall at 1000hrs. The engineer running with the wall had booked a load for 1200hrs and happened to be walking down the site with the total station to check the vertical alignment at the top of the shuttering, steel configuration, heights, cover etc when he saw this diverted lorry trundling over to the wall. He immediately stopped the contractors pouring it into the skip for the wall and told them he had about an hours worth of checks to conduct prior to the pour. This was barring any alterations that needed be made, of which I might add there are generally not many now as this is the 7th 15m section of wall to be poured and we have been fairly meticulous with what we expect from the contractors. Needless to say this ended up with a stand up row between the engineer and the sub-contractor with loads of swearing and phonecalls to this foreman. After the sub-contractor had calmed down the engineer told them to go for lunch and he’d have it all done by the time they returned. The concrete standing concrete wagon was used elsewhere and the original 1200hrs load was slightly brought forward. It appears that the only reason this particular subcontractor was so upset was the fact he wanted to cut away earlier on the Saturday, understandable but no reason to risk the quality of the final wall particularly when we (as engineers) have to quality assure the final product for the client.
I also believe that one of the reasons for this lax attitude is the lack of client by-in on this site. I have written in AER 2 that part of my pre-pour paperwork is to notify the client and designer of our intent to pour for them to conduct their own pre-pour checks. Of the 11 previous bases I poured (550m3+ of concrete) only 1 was inspected prior to pouring the concrete. I believe this has led to a general malaise in the concrete quality procedures, vital in this a marine environment, across the site. My feeling is this is partly due to the inexperience of the clients representative charged with the inspections and it could be a problem if a non-compliance report was ever to be raised by them,