Concrete piles in Blackpool

 The random selection of vertical concrete columns in the middle distance are called concrete piles. The issue here is that the solid rock will be under a layer of weaker soil, possibly quite sandy being near the beach. All you need to know about piles is here http://www.understandconstruction.com/pile-foundations.html It looks like these were probably pre-cast and then driven in with a pile driver.

Then it looks as though the foundations of the buildings are laid across the piles. The concrete is poured around the steel frame to make reinforced concrete. This is because concrete is strong when loads are compressing it but is weak and cracks easily when stretched. The steel provides the resistance to stretching. The combination of concrete and steel is lighter and cheaper.