Muckleford Creek Bridge is certainly on the way to needing a new deck, which as I’m sure anyone can imagine is an enormous amount of timber at an enormous cost! Given the last decking has really only lasted 30 years (and the other bridges are hinting at a similar rate of decay), it’s time to seriously consider alternatives.
One such alternative that we’ve decided to trial is Recycled Plastic, and today was the day we took that trial from paper and put it into practice.
So we began by removing a short section of the old deck at the very down end of the Bridge, which is nice and low, straight and good easy access, important things when trial fitting the new deck.
The panels that we made up last week were then lifted onto the bridge, slewed under the rails from the side, only a small amount of rail jacking was required to achieve this.
We then simply continued that process two and half more times to get the rest of the deck in, which actually did end up being very easy, with very little to no manual input required. We’re looking for a solution that means we can do these sorts of works without having to do the work at heights, hence this method has proven to be very effective, with the construction taking place on the ground.
We expect it would look very noticeably different to the timber, however it’s not as different as we expected, it slightly narrower, due to the available length of plastic, however otherwise pretty much identical dimensions to the timber decking, so it’s not really a massive change.
The final appearance is probably a little too neat for a typical timber bridge, a bit too uniform.
We were extremely pleased with the ease and speed with which it was installed, it was a learning curve and no doubt we could speed up the process significantly if we need to.
We gave up when it looked like the rain was about to hit, however tomorrow is a day of finishing fastening up the sleepers (plastic also, as we do want to get a option which is essentially maintenance free going forward), ballasting, tamping and running a testing and commissioning train to verify the design as suitable.
There won’t be any issues structurally, as the rails are directly over the beams, so the decking serves no more purpose than just to contain ballast, and transfer the load straight down to the beams, any issues will be more if the modified design with no tie rods and through bolts is sufficient to prevent movement of the kerbs, which is really a thing that’ll take a few years to evaluate, but it’s an extremely easy fix if we find an issue – just add them.
Tomorrow’s crew will be meeting at Maldon at 8am, where we will need a few truck drivers (Mick.. if we get this), then at the Bridge from 8.30am.
VGR Civil Blog 