Pile Foundations – Name of a pile that carries load by both shaft friction and end bearing In foundation engineering, what is the correct term for a pile that derives part of its capacity from skin (shaft) friction along the pile–soil interface and the remaining part from end bearing on a firm stratum?

Introduction / Context:
Pile capacity is mobilized through two primary mechanisms: shaft (skin) friction and end (toe) bearing. In many practical sites, neither mechanism alone dominates completely; instead, a pile behaves as a composite element where both contributions matter. Identifying the correct terminology helps in interpreting calculation methods and test results.

Given Data / Assumptions:

• Pile embedded through layered soils with a competent stratum at depth.
• Axial loading considered under service and ultimate states.
• Both shaft friction and toe resistance are mobilized under load.

Concept / Approach:

A purely friction pile develops capacity mainly through skin friction along its embedded length, typically in soft or medium soils without a firm bearing stratum. A purely end-bearing pile transfers most load to a hard stratum at the toe. When both mechanisms are significant, the correct description is a friction–bearing pile (also written friction-cum-end-bearing pile). Design sums the two components, often with reduction factors for compatibility and settlement criteria.

Step-by-Step Solution:

Verification / Alternative check:

Pile load tests (maintained load) show settlement–load curves where both shaft and base contributions are mobilized progressively. Static formulae integrate unit skin resistance and base resistance; dynamic correlations recognize both mechanisms as well.

Why Other Options Are Wrong:

“Friction pile” implies negligible end bearing; “bearing pile” implies dominant toe resistance; “rough pile” is not a standard term; “floating pile” usually indicates no firm toe stratum.

Common Pitfalls:

Assuming linear addition without considering settlement compatibility; overlooking negative skin friction; ignoring partial mobilization under service loads.

Final Answer:

Friction bearing pile (combined action)