Cutting shape out of surface

Apologies because I’ve only just started using rhino, but how should I cut shapes out of a surface that I made after lofting two curves? I’ve tried to make an array and then use flowalongsrf, but when I cut the shapes, the original surface still remains. I’ve attached what I have so far, and the bridge in the background of this image is what I’m trying to make. Any help would be very much appreciated alishon model.3dm (470.1 KB)

Hello - it’s not clear what surfaces you are asking about but the ones on the side need to be re-made - if you are looking for something between the two curves, that is not the way to do it… I guess I’d suggest going trough some basic surface construction tools in Rhino first so you can start with a little more in your arsenal to make these shapes.