Holdfast Training Services Trial Blog

This week has seen yet another significant concrete pour, and actually a milestone we hit! Once again there were several issues though. Reliance upon the sub-contractor to do what he is meant to do is actually more of an issue than it would seem. I have organised pre-pour meetings with all the involved sub-contractors and managers in order to inform, discuss and resolve potential issues for the last 5 suspended slab pours (I even have an “Actions On” section in the minutes) but it appears that no matter what is decided the contractor tends to do what he wants to anyway. This recent pour of Zone 6 was no exception. It was a relatively large at 330m3 and incorporated a mix with the addition of Xypex for a small area of the slab. It was to be pumped from the semi-permanent concrete pump in the slip-lane through about 130m of 150mm diameter pipeline on the boom mast. The issue with this pour is that the 3^rd mast is not yet operational, and therefore the 2^nd was used which didn’t quite have the reach (this meant time consuming pipe connecting, and the inevitable blockages each time).

The pour was due to start at 0700 but due to rain during the night, the client declared that the falsework required an additional inspection before the State was happy to sign off on the pour card to let the work commence. This delayed the pour to 0800. The pour was then delayed to 0900 as the concrete sub-contractor had not moved the required tools across the night before (as agreed in the pre-pour meeting). As the concrete arrived there was a brief shower of light rain which resulted in the concreters retiring under cover stating that they don’t work in the rain. This added an extra 30mins to the start, whilst I had to call the sub-contractor to sort the situation. Once the inevitable blockage was cleared the pour started at approximately 1000. I was not considerably worried about this, as I know that once the pour has started it will continue until complete and it really will be a case of “You’re in your own time now.” So the incentive was on them to work efficiently. As the pour progressed I became increasingly aware just how lethargic the concreters were, there was just no sense of urgency. Concrete was continually at the pump throughout the day – I was actually pleased with the JHG performance during the day – yet it just wasn’t being placed as quickly as required. The pour finished at 2030, approximately 10.5hrs after starting. JHG laid on pizza for the late workers, but I decided that I was not going to wait around until they had finished the surface correctly. They eventually finished at 2330.

On inspection in the morning it was clear what an awful job had been done. Unfinished surfaces, badly floated surfaces, holes in the top, aggregate showing, undulations in the surface, and even footprints. I had a walk around with the camera to record the post pour inspection. The most striking issue was with the use of Rugasol. Rugasol is a chemical agent that prevents the cement past bonding with the aggregate to a depth of about 4mm in order that post pour the construction joints at column tops and upstand walls can be water blasted to a good scabbled finish instead of chipping them out. The rugasol application on zone 6 was pretty liberal, and not confined to the columns and walls. This coupled with the undulations meant that the fluid had spread around the CJ’s damaging large areas of the surface. I raised all these issues with the PM and Site Manager, supplied the evidence and then sat back as they went into battle. The remainder of the non-conformance points will be raised in the project pack for resolution.

Rugasol spillage around upstand wall

Zone 6 – the day after (note the puddling in the undulations)

During the recent concrete pours I have become aware that the management of the pour is dominated by JHG personnel, who take a lot of abuse for pretty much any issue. I was not overly happy with this as it is usually me that takes the brunt of it. Whilst I was delving into the sub-contractors contracts to build the cases for later arguments about the NCR’s I noted that the concrete sub-contractor was actually responsible for calculating concrete quantities, receiving concrete onto site, and managing the actual pour and that the concrete supplier should have a representative on site to manage the trucks. I proposed to my PM that the concrete pour is broken down into stages.

1. Preparation.  Managed by JHG. Engr continues to calculate concrete quantities and types. Site Manager orders and briefs sub-contractor of when it will occur. Pre-Pour meeting as normal.
2. Delivery.  The concrete supplier is responsible from batching to delivery onto site. He manages the trucks ensure that no more than 3 are waiting in the slip lane at any time (Maximum allowed in Safety plan). The concrete sub-contractor receives the trucks and marshals them in order to the pump. The JHG engineer tests to ensure quality.
3. Placement.  The concrete sub-contractor is responsible for the pouring of concrete and calling in the excess to finish the slab as necessary.

Risk-wise, I think JHG had put too much on the line by involving the Engr and Site Manager so heavily. The sub-contractor is being paid to take the risk, so he should take it. (By all accounts they are actually quite keen to do it). I have drafted a concrete management plan that I have thrown around the Engrs and Site Managers and will submit to the PM this week to get it signed off. Nothing official really, more of a Memorandum of understanding to ensure that the sub-contractors are aware of what their responsibilities are. There is even a task-org in it. I think the Sync Matrix was pushing it!

WA has its fair share of public holidays, so Nicky and I have made the most of this long weekend by driving down to Margaret River, 3hrs south of Perth to spend some time with mates in the wine and surf region. I finally managed to get in the water on Sunday. It wasn’t as big as I would have liked, but the reef that was only 4ft below the waterline was incentive enough not to wipeout too heavily – Success, you’ll be pleased to hear. We returned today with a heavily laden car full of wine and a very unheavy wallet. This week sees the British and Irish Lions visiting Perth. I don’t think productivity in the site office will be high on Wed afternoon. Nicky and I are catching up with Steve and Fay and a few other mates, so it should be a good night. Having attended Western Force’s fixture last Saturday, I do not predict any real issues for the Lions. Potentially a 3 figure score.