Holdfast Training Services Trial Blog

This week has seen more significant progress as we completed abutment B by thu and were able to strip the shutters on fri in time for the Queens Birthday long weekend which means no work on site until wed this week. The timings are now very tight to get the PSC beams in place over three days before we need to give the centre of the site over to the civil team to lay capping etc for rail to come through. Abutment A more than met the class 2 finish required and the as-built survey is all within tolerance except the position of the abutment dowels which I noticed when we were installing the dowels on abutment B. The stainless dowels are cast into the top of the abutment 210mm from the outer edge of the wall and 340mm from the centre of the wall, unfortunately the formworker placed the dowels with these measurements the other way around so that they are out of alignment by 130mm to far to the centre. As yet we haven’t raised an NCR as no one but myself has picked up on it but as it was my fault for not noticing when I did the pre-pour checks (a classic case of not seeing the wood through the trees) I informed the Project Engineer who’s repsonse at the moment is – we’ll have to cross that bridge when we come to it (I don’t think the pun was intentional!). The dowels connect the abutment to the diaphragm allowing lomgitudinal movement and then a further set of dowels are cast into the top of the diaphragm to the approach slab. I suspect we will place an NCR and RFI following the PSC beam installation as at the moment we don’t want anything to interfere with thoses dates. We have had minor surface concrete cracking of around 0.2mm on both abutments which we have had to submit NCR’s for but which are straight forward to rectify with a product called Megapoxy H. Although this is standard practice throughout the project for cracks that are out of the accepted tolerance (0.5mm post curing period and 0.1mm after 28 days) for us it still eats into time we don’t have waiting for repsonses to RFI’s and NCR’s in order to be ready to install the beams on wed morning.

As part of the AMS I have had to recce the route for the delivery of the beams and produce a Vehicle Management Plan for the drivers to aid the coordination of the trucks approaching and entering site. Eack beam is 18m in length and weighs 16T and will be delivered on extendable trucks. The access to site is not the best after the civil team have dug up various parts and placed piles of earth in odd places which means we have had to wider the route in places by ordering a few hundred tonnes of recycled balast to lay down. This has not been welcomed by the civil team who have told us we will have to make sure we get rid of it all ourselves as it is not the required spec for fill that they can use. This has been somewhat annoying as it is their job to provide the required access for everyone working in the area but as we can only really relay onourselves when we have a tight timeline we have eaten into our budget to make it happen. I have also been badgering the geotech to certify the crane pad where our 220T crane will sit. The outriggers sit on a  9m square area which is causing a few problems as although the ground in the centre is more than adequte towards the sides it becomes somewhat sloppy. I spent fri laying some more recycled balast down to all-weather the area in case we had rain over the weekend to the slight horror of the geotech engineer who would have rathered we left it as is. The ground is solid and there has been structural fill laid by the civil team but as we couldn’t get hold of a heavy roller we did the proof roll with a bogey (single truck) which comes in at 11T. We had the 55T crane still in the middle at the time so when they left and rolled over the crane pad the noticeable ruts it left didn’t fill me with agreat deal of confidence of a pass. Sure enough we have a re-show to do on wed morning by which time we have borrowed a heavy roller to properly compact the top layer.

We also managed to pour the outer bas slab of the final deflection wall and the wall part of the adjacent outer deflection wall which just leaves the wall of the recent slab pour and then all the inner wall segments that will be flush to the abutment walls. In order to proceed with those we need to alter the scaffolding once the beams are in place so that we can backfill the area up to the abutments. We comtemplated changing the programme again so that we moved straight onto the deck and diaphragms as the sub-contractor is now struggling for work. As this is the last structure to start and finish all the other strauctures are close to finishing with only FRP work required at Edmonson Park station. This has meant we have had a surge of manpower from them but the time needed to install the beams will mean they may go off onto other jobs leaving us short staffed for the reminder of the work as their priorities change. Construction work around Sydney is apparently not looking good (for them) so they have staretd to lay off alot of their personnel. In fact there only seems to be about 4 people left after the last cull which may mean I might have to get some concreteing qualifications pretty sharpish!