... 3137_290125_120000000.jpg 3137_290125_120000001.jpg The shiny discs were home designed pressure cells to measure the contact pressure between the fill and the arch ring. I also watched the demolition of an arch at Cargill on the old Caly main line from Perth to Aberdeen that was just up the road from where we lived at the time. A lot of time and money was wasted installing explosives into the arch when all that's needed is to simply lift the crown. Anyway the photo below shows the digger sitting on the solid masonry backing above and behind the abutment. 3137_290125_120000002.jpg It looks like I will be on site assisting with the monitoring of a railway viaduct later in the year when these current restrictions are lifted. As I said, arches are interesting. Cheers Fraser posted: 29 Apr 2020 23:25 from: Andrew Duncan Martin Wynne wrote: Andrew Duncan wrote: It prompted me to check the photo I have of the real bridge and compare it with my model. Here are a couple of shots. The first is the model that has a white card infill (not yet properly ...