This seems to happen most often when play speed is higher, it might just be a 'placebo' effect, but you could try hitting 'space' to pause the game while the terrain tables are rebuilt, and then resuming.
Not seen it in the stock scenarios for a few builds, but I did have one on 'bridge construction' this morning in a large custom scenario.
Otherwise, to minimise disruption/lost play, either run with 'save every 20' on, or manually save (before) when you expect bridges to complete or be destroyed.
If you find that one of these saves won't play normally and CTDs, then send it to Arjuna for him to test.
Bridge events are sparse, so it takes a few runs to get even one error...
< Message edited by Lieste -- 5/9/2012 1:16:00 PM >