Pile load transfer: end-bearing vs friction

One-line orientation

A deep pile transfers load in one of two ways — end-bearing (load at the tip on rock) or friction (load along the shaft) — and the exam tests which mechanism matches which soil profile.

Key points

• End-bearing pile:
  • Transfers load directly to firm soil or rock at the tip.
  • Used where a firm stratum/rock is within reach — the pile acts like a column down to that layer.
• Friction (floating) pile:
  • Carries load by friction between the pile surface and the surrounding soil along the shaft.
  • Used in deep soft soils where no firm bearing layer is economically reachable; the pile relies on its embedded length rather than a hard tip.
• Material note: timber piles are commonly used as friction piles.
• Real piles often combine both effects; the classification names the dominant mechanism.

Confusions / comparison

	End-bearing pile	Friction (floating) pile
Load transferred at	Tip	Along the shaft
Mechanism	Point bearing on firm layer	Skin friction with soil
Soil condition	Firm stratum/rock within reach	Deep soft soil, no firm layer reachable
Acts like	A column to bedrock	A member gripped by surrounding soil

Related

→ Deep foundations: piles vs caissons (this topic): driven vs drilled, pile cap, materials · Caisson types (in the piles-vs-caissons card): rock/socket/hardpan vs friction caisson mirror this same bearing-vs-friction split · Settlement (this topic).