---
title: "Define and classify pile foundations"
subject: "Foundation Engineering"
chapter: 8
key: "semester_5/foundation_engineering:pile-classification-define"
source: https://www.bctengineer.com/q/semester_5/foundation_engineering/pile-classification-define
site: BCT Engineering
---

# Define and classify pile foundations

Foundation Engineering · Chapter 8: Pile Foundations

- Asked in: 2081 Baisakh, 1+3 marks
- Video: [Classification of Pile Foundations based on Different Criterias | Geotechnical Engineering](https://www.youtube.com/watch?v=lk6ywtdUulI) — Geotechnical Engineering Consultancy
- Answer checked by Claude Sonnet 5.5 on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_5/foundation_engineering/pile-classification-define
- Whole chapter: https://www.bctengineer.com/md/semester_5/foundation_engineering/chapter-8

## Question

Define pile foundation. How do you classify pile foundation based on (i) materials (ii) methods of installation and (iii) load transfer?

## Short answer

A pile foundation is a group of piles connected by a cap, transferring loads to deeper, stronger strata. Classified by material into timber, concrete, steel, or composite; by installation as driven, bored, driven cast-in-situ, or jacked; and by load transfer as end-bearing, friction, or combined.

## Answer

**Pile foundation:** a pile is a long, slender structural member of timber, concrete or steel, driven into or formed in the ground to transfer the structure's load to a deeper, stronger stratum or to the surrounding soil by end bearing and/or shaft friction. A pile foundation is a group of piles connected by a pile cap.

#### (i) Based on material
- **Timber piles:** economical and light, used for light loads and temporary works; need protection from rot and borers above the water table.
- **Concrete piles:** precast (reinforced or prestressed) or cast-in-situ.
- **Steel piles:** H-piles, pipe piles (open or closed end); high load capacity and easy to splice; prone to corrosion.
- **Composite piles:** two materials, e.g. timber below the water table with concrete above.

#### (ii) Based on method of installation
- **Driven piles:** installed by hammering or vibration (precast concrete, steel, timber); displace soil.
- **Bored (drilled) piles:** a hole is bored, then filled with concrete (bored cast-in-situ).
- **Driven cast-in-situ piles:** a casing or shell driven, and then filled with concrete (e.g. Franki, Raymond).
- **Jacked and screw piles:** pressed or screwed into ground where vibration must be avoided.

#### (iii) Based on load transfer
- **End-bearing (point-bearing) piles:** pass through weak soil and rest on rock or dense soil; load is carried mainly by the tip.
- **Friction (floating) piles:** carry load by skin friction along the shaft in deep soft soil.
- **Combined (friction and end bearing):** most piles in practice.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. A pile is:
   A. A short wide footing
   B. A long slender member transferring load to deeper strata or surrounding soil
   C. A retaining wall
   D. A raft
   Answer: B. Piles transfer load via end bearing and/or shaft friction. (Key point: Definition)

2. A composite pile is:
   A. Of two materials, e.g. timber below water and concrete above
   B. Only steel
   C. A group of piles
   D. A bored pile
   Answer: A. It combines two materials. (Key point: Composite pile)

3. Franki and Raymond piles are:
   A. Driven cast-in-situ piles
   B. Timber piles
   C. Bored piles
   D. Screw piles
   Answer: A. A casing or shell is driven and then filled with concrete. (Key point: Installation)

4. Piles that pass through weak soil to rock are:
   A. Friction piles
   B. End-bearing piles
   C. Tension piles
   D. Fender piles
   Answer: B. Load is carried mainly by the tip. (Key point: Load transfer)

## Related in Foundation Engineering

- [Classification of pile foundations](https://www.bctengineer.com/question.md?key=semester_5%2Ffoundation_engineering%3Apile-classification-material-load) — Foundation Engineering, chapter 8
- [Classify shallow and deep foundations](https://www.bctengineer.com/question.md?key=semester_5%2Ffoundation_engineering%3Aclassify-foundations-soil) — Foundation Engineering, chapter 1, asked 4×
- [Why foundations; types of foundation](https://www.bctengineer.com/question.md?key=semester_5%2Ffoundation_engineering%3Awhy-foundations-types) — Foundation Engineering, chapter 1
- [Pile capacity in sand, group effect, load test](https://www.bctengineer.com/question.md?key=semester_5%2Ffoundation_engineering%3Apile-capacity-sand-group-load-test) — Foundation Engineering, chapter 8
- [Allowable load of 4×4 pile group, layered sand](https://www.bctengineer.com/question.md?key=semester_5%2Ffoundation_engineering%3Apile-group-4x4-figure-dcr) — Foundation Engineering, chapter 8
- [Allowable load of 400 mm pile, layered soil](https://www.bctengineer.com/question.md?key=semester_5%2Ffoundation_engineering%3Apile-400mm-layered-soil-chart) — Foundation Engineering, chapter 8

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- [Deep foundation types and use of shallow foundations](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Adeep-shallow-types-079a) — Building Technology, chapter 2
- [When pile and mat foundations are chosen](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Apile-mat-scenarios) — Building Technology, chapter 2
- [Situations demanding pile foundation](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Apile-situations) — Building Technology, chapter 2, asked 2×
- [Foundations on black cotton soil](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Ablack-cotton-foundation) — Building Technology, chapter 2