Saturday 31 March 2012

EWB Imperial - building a log bridge in the woods

Last weekend members of EWB UK from Imperial College London came down for what's become an annual camping trip to our woodland. As always, there was a project to get involved with - this time building a bridge over a stream that can support a vehicle! During previous visits they built a firewood shelter and a foot bridge, so this year was a step up in scale.

I made a timelapse video of most of the bridge building, it's about 7 mins long (it's in 1080p HD, so put it full-screen). Take a look, and then read the rest of the post to see the pictures and description.

Here's the full team that came down this year:
DSC_3710 EWB Imperial members

The bridge is needed to allow access to a new ride that I cut last winter. I saved some of the stems I'd cut to make parts of the bridge, and we felled a few others as required to complete it. The first steps were digging some foundations, which took quite a while:
DSC_3704 Building a log bridge

and peeling the long logs that were going to be used as the main supports:
DSC_3708 Building a log bridge

We put some chunky logs into ditches that had been dug on each side of the stream:
DSC_3718 Building a log bridge

and then got the main supports in place, bolting them down later on:
DSC_3723 Building a log bridge

In the centre of the stream we also drove in some stakes (see the timelapse video above), and I used the chainsaw to cut a notch in the top of them for the main supports to rest in:
DSC_3726 Building a log bridge

On top of the main supports went some crossbeams (all of this was Sweet Chestnut, by the way), and again I cut some notches for them to sit in:
DSC_3731 Building a log bridge

Then there was a lot of drilling and nailing...
DSC_3737 Building a log bridge

Some of it by hand:
DSC_3738 Building a log bridge

though we did have a solar panel and inverter on hand to recharge the electric drill:
DSC_3727 solar panel

DSC_3729 inverter and battery charger

Once that was finished, it was time to start making the ramps to lead on and off the bridge and also lay down some planks (the only bit of wood that was bought in for this):
DSC_3739 Building a log bridge

DSC_3744 Building a log bridge

The planks were also nailed down, and it was starting to look like it might be OK to drive on...
DSC_3746 Building a log bridge

Of course, there's a signature on the side of the bridge:
DSC_3747 EWB signature

We posed for a photo or two:
DSC_3754 EWB Imperial members

DSC_3753 EWB Imperial members

and then it was time to put it to the test...
DSC_3758 Car approaching log bridge

There were some creaking noises, but it was rock solid!
DSC_3760 Car on log bridge

A job well done - thanks to everyone who came from EWB Imperial to help with this!


1 comment:

Anonymous said...

Good to see some student labour being put to practical use!!

Is the wood used a hardwood?