What are the different types of piles and their applications?

Piles are classified by material (concrete, steel, timber), installation (driven, bored/drilled), and load transfer (friction, end-bearing, combined). Driven piles displace soil and are suitable for sandy soils. Bored piles remove soil and work in all conditions including rock. End-bearing piles transfer load to strong stratum at tip. Friction piles develop resistance along shaft in uniform soils. Selection considers soil conditions, load requirements, site constraints, noise/vibration restrictions, and cost.