Thats Peace of cake! But donīt use PVC Tubings. Its a mess to cut lenghtwise and you have to use a Rotoknife like a Proxxon Multicutter for that Job. If You really want to build something like this I would make 5 masters with nice finished textures inside and would build a Tubemould to cast the Stuff in Polymerplaster. Count on the whole table its nearby the same Money, but overall much less work and a solid quality till the end of the project when its begin to become ugly and you just want to end it up.
hum, i'd go with cardboard tubes (the one for the fabric, for example) and casting thin layer of resin for bricks or concrete. Something like this, casted by myself (and now sold by Fenris Games)
that's definitely the cheaper solution, and cutting the cardboards tubes will give you more freedom... of course, when you need curved sections you can easily use pvc or other cheaper tubes too!