
You could always get sheets of HIPS, scribe stonework on then block out the existing supports with some more wood and make a proper viaduct. Wood would be well protected against the weather above ground. But a lot of scribing and work! Not sure about your site but you may be able to get away with only doing one side.Yes, thanks Paul. The old brain was ticking in that direction - slowly!
Trying to find a simple but long lived way of making them taper outwards as well.
JonD