Saturday, March 23, 2013

Bridge stages

The original arch of this unfinished bridge had temporary stones fitted into it and unfortunately the project had to be abandoned by the builders before it was completed. Several of the single full length voussoirs which extended beyond the width of the bridge had slipped down since then. The design was an ambitious one that would likely have worked had they been able to finish it, but after considering all our options, including looking at what material there was to work with, we felt it was better to take down most of the arch and rebuild it.

The first stage of our work involved building a wooden crib of pallets under the arch to 'catch' most of the big stones which would fall when we removed the huge keystone and the heavy middle voissoirs.

 We strapped the stones and lifted them with a Gradal forklift. 

The next stage involved making a sturdy platform to support the centering which we had to design/construct to support the stones in the new dry stone arch. 

This 'centering' (also called 'falsework' or a 'former' ) wasn't going to be the usual type of arch form that I've employed on other bridges. This one was not going to be made of wood. Stay tuned to see what it looked like.