Friday, 12 February 2016

Concrete is poured

Thursday saw the footings fully dug out during a beautiful, sunny day:

... and today was the day for the big concrete pour. The  logistics of building at Hayles are not easy, and some headscratching preceded the solution adopted for the job, where the far end of the pour was about 80m from the delivery lorry. The solution was to hire in a concrete pump with a 60m range, and then to use the dumper for the last 20m.

Here you can see the truck with the pump, and the first of initially two delivery trucks with 6 cubic meters of concrete each. The path down to the former waiting room was cleared, and the pipe elements laid along it. It was quite a job, as the outside temperature was only 2.5 degrees, and the constituent parts proved very stiff and rather unwilling to fit together easily. But we got there.

Here the pipe emerges form the pump truck, and goes down the newly refreshed path towards what was +/- the centre of the platform.

The pump is a based on a  piston, which was duly set to work, and all eyes were fixed on the end of the pipe to observe 6cu m of concrete pouring out, about a wheelbarrow load with each push.

Alas, it was not to be. Although more fluid, pumpable concrete had been ordered, standard type with larger ballast in it was delivered, and it wouldn't pass down the pipe. A second lorry with the same mix had also arrived in the meantime. Now what?

After an inspection of the site to see what alternatives it offered, it was decided to cut a track up to the other side of the cutting, and to run the dumper up along the edge and to the mixer lorry, repositioned on the road on the Malvern side of the bridge.

This worked really well. Here you can see Steve in the 6 ton dumper 'drinking' liquid concrete straight from the mothership. Notice how he has tipped the bucket a bit to keep it level.

When Steve reversed back down, we all eagerly expected to see a wave of liquid concrete gush over him, but we were sadly disappointed. He handled it beautifully, running back down to the track where he poured it into the trench. Graham's brand new Hi Viz jacket remained pristine.

The first two mixer loads were dispatched in this way. After a number of calls to the plant to remind them of what exactly we had ordered, the next 4 lorries arrived with the correct mix, which the pump lorry was able to handle as planned.

In the photograph you can see how the end of the pipe was lifted into the dumper, and the full load was then run up to the far end of the trench, as per original Plan A.

Good progress is visible in this picture, where the furthest section has already been tamped level, and fresh concrete is arriving, per pump as planned, into the central piece.  Here Steve is raking it in around the catch pit, which will be incorporated into the platform wall and accessible via a hatch.

This employee is testing a pair of Mafia type boots... don't stand in there too long, Steve!

Due to the initial delays, the pump had to leave before we had handled the last of the 6 deliveries. Once the mixer has stopped emptying concrete into the hopper on the pump lorry, there remained quite a bit of concrete left in the pipe. This is forced out with a sponge, which erupted from the end like a little cannon ball.

The solution to the problem of the pump leaving early was to resume the loading of the dumper by the bridge. Here you can see one of the last loads going in; also the end of the path top right (it is not quite fully dug out yet) ending near the depression which marked the location of the corrugated iron waiting room.

At the end of the day the concrete pour was completed. We will now wait for it to go off. Once materials have been delivered to the site, we will start laying the concrete blocks in two rows, perhaps in a week, 10 days.

This last picture shows what faces those who get off at Hayles Abbey Halt - the beautiful Cotswolds. The ruins of the abbey are 900m away down a small road on the right. The Cotswolds way runs across this photograph from right to left. Anyone for Hayles Abbey Halt?

BTW, for those interested in Broadway, here is a video of the second footbridge tower being erected:

1 comment:

  1. Excellent work in such awfully cold weather. Certainly wetter down here in St Blazey. My heart goes out to all working these temperatures.