Monday 28 December 2015

The Committee Visit to the orchard

The Committee undertook its annual inspection visit to the Turnditch Orchard Project this morning to assess the work done by the Management and Volunteer Team. They expressed satisfaction with the progress of the work. The visitors retired to a local pub shortly afterwards to celebrate the success.

Monday 21 December 2015

More trees in the orchard

We were able to plant some more trees in the orchard at the weekend. We planted a Medlar tree (Nottingham), an American Red Oak and a Ginko tree. We also covered the concrete beam by the gate with soil, so other than the fence post no trace remains of the civil engineering work.

Ginko Leaves

Medlar fruit and leaves
Red Oak

Friday 18 December 2015

Why are things never simple in the orchard?

Finally on Thursday we were able to pour concrete to form a beam to support the new gate post and fence posts on the top of the river bank at the Turnditch orchard. The beam is about two metres long and approximately sixty cm square in profile. It took roughly 2/3 of a cubic metre, about 1.5 tonnes, of ST4 grade concrete with added polyester fibre to reduce cracking to complete the beam.  The actual pour process only took about 30 minutes from the time the mixer lorry arrived. We now have to leave the beam for a couple of weeks to harden somewhat before setting up the posts. 

Concrete beam supporting gate post

In the picture you can see the fence post cast  in place. It looks a bit tilted, but that is just caused by the camera angle. According to the  builder's level it is well squared and vertical. At the base of the post you can make out a couple of layers of plastic bubble wrap. This was added to increase the diameter of the post socket hole in the concrete. We'll lift the post, remove the bubble wrap, and then reinstall the post with dry sand packing. This will allow subsequent removal of the post for maintenance without damage to the concrete beam. 

You can also see a dummy post embedded in the concrete. This also has bubble wrap and acts as a form for the socket hole in the concrete for the gate post. When we are ready to install a gate post we'll pull out the dummy post leaving a clean hole for the new post. 

There is a matrix of steel reinforcing bars hidden and embedded in the concrete to strengthen the beam. The steel is carefully designed to resist the potential stresses from the posts. During the next few days we'll cover up the concrete beam with aggregate/soil from the original hole so people will be unaware of the minor civil engineering buried beneath. As mentioned in an earlier post this work will help to prevent river bank collapse so close to the road bridge. 
It was a lot of work, when all we were expecting was to drive a post in for a short fence on the river side bank.

Wednesday 2 December 2015

Civil engineering in the orchard?

As we work through the plans for the gates to the orchard site it is beginning to sound like a civil engineering project. We've worked out we'll need about half a cubic metre of medium strength concrete to cast the beam required to support the riverside gate/fence posts. We've phoned around various suppliers to discuss the options and it seems a mix-to-order truck which mixes the concrete on site is the best option. A local company J C Balls provides a suitable service at a reasonable price. 

Fortunately where we are working is close to the roadside so delivery is not a problem. We'll just need a robust wheel barrow to move the concrete to the place we need to pour. The truck is charged in half-hour timeslots.

We're going for a concrete ST4 mix with polyester reinforcing fibres. We've now received the re-bar for the steel reinforcement of the beam for Twiggs, so all that remains for us to do is to dig out the trench for the beam and install some 18mm plywood shuttering to create a form for the concrete. We'll then position the re-bar and wire tie it in place before pouring the concrete. We need a 7 day period to allow the concrete to cure and gain strength, prior to installing the gate/fence posts.

The rebar awaiting installation, and wire tie equipment.

All this effort is necessary so we can set the gate post and the fence post in such a way that it will provide sufficient strength of support without creating risk of damage to the slope down from the road. The gate post will be exposed to frequent use by the public as they open/close the gate for their dogs as they make use of the public footpath. A gate post just driven or dug into the limestone chippings of the slope will inevitably fail within a few years. We mentioned in an earlier blog posting that we'll leave the historic stone gate posts and stile in place.

Once we have the gateposts installed we'll build a pair of wooden gates to match the distance between the posts. It will not be a standard gate size and we have to allow for footpath access, so using "off the shelf" gates is not an option..