Holdfast Training Services Trial Blog

The last two weeks since returning from Tasmania have been rather hectic. It was nice of my site engineers to leave everything untouched so that it took the first week just to catch back up.

The Form, Reo, Pour process is now in full swing for the pilecap and column section of the substructure. There have been a few teething issues with the formwork, particularly where the pilecaps interact with the columns. This is now resolved and we’re pouring about 2 pilecaps and 2 sets of columns every week, with 2 headstocks soon to be added to that weekly tally. The 280t crane has also arrived on site and been commissioned, ready to lift the girders…if we ever get any.

The changes to the reinforcement in the headstock were finally approved after a meeting with the us (main contractor) the steelfixers (our subby), the clients rep (on site inspectors) and the designers (AECOM). We came to a workable option that satisfied our need for prefabrication and the designers need for torsional reinforcement. Though I still can’t understand their concern when we only needed to change a small section of bars. I did quiz them but got nothing back. I’ve also seen the cage successfully lowered into the bathtub (formwork) and the pour is planned for tomorrow.

There have been issues up at the precast yard recently that I will probably cover in another blog, as the safety investigations are on going. As a bit of background john Holland have built their own precast yard for this project to make the 700 or so girders for the 2 bridges. These are 35m long prestressed pretentioned girders with a lot of strands in them (I’ll get more info in the following blog). The first incident was a prefabricated section of reinforcement for the girders toppling over. While no one was injured, due to the size of the cage and potential to harm this is being classed as a 1P incident (notifiable to the Aussie equivalent of the HSE). The second was during a girder pour 4 strand couplers failed while in tension. With 200KN on each strand this was really dangerous. I will get some of the photos of them smashing through some wooden boards and into the stressing trench wall. Again no one was injured as the controls were in place to stop this. I’ll get more details when I can. Without wanting to second guess the investigation the control appear to have been in place, and as they have let us continue work they must be pretty happy with the process and controls.

The piling crew has now kicked things up a gear and one rig managed to install 8 piles on its own yesterday, when they are only planned for installing 4. This might have a major impact on the supply of piles to keep the rigs busy. At this rate they will catch the casting program in 4 weeks time. To mitigate this the plan is to split the rigs and send one over to start bridge 2 early. All the piles on bridge 2 are spliced and this will slow the rig down considerably. It will also buy more time for me to prepare everything for the cofferdams that are needed for pier 1 and 2 in scrubby creek.

There have been a number of minor dramas and modifications to the headstock formwork to get it to the stage shown in the photos. The first drama was the project manager not approving the purchase order for the stressing jacks in time to get them on site! I’ve now had to go to VSL at short notice and get them here to fill the gap till I could get some kit here (as it happens I got a bargain on some kit from another JHG job that is coming to a close). Trying to rush through a short term subcontract has been a nightmare, mainly due to the terms and conditions that VSL work under. They only want to be liable for 5% of the contract value, but as the contract may only be a few thousand dollars this just isn’t acceptable – if their stressing fails the damage could be in the tens or hundreds of thousands of dollars. However, I’ve managed to get someone onto site though a bit of a loophole (but with the commercial managers blessing).

In other news I would thoroughly recommend Tasmania for a holiday – it was great, and they have even named a lake after me. Went and did the Gold Coast Half marathon with Ben and Sharna (though Ben managed to pick up an ITB injury that meant he had to withdraw, so he consoled himself with a few drinks).