Piling is a crucial part of civil engineering works, providing deep foundations where surface soils lack bearing capacity. Class P defines how piles and associated works must be measured, itemized, and described in the Bill of Quantities (BOQ).
1. Scope
Class P covers:
- Supply, installation, and testing of piles.
- All types of piles used in foundations: cast in-situ, precast driven, bored, screwed, micro-piles, continuous flight auger (CFA), diaphragm walls (if used as piles), etc.
- Associated operations like driving, boring, concreting, reinforcement, and pile testing.
2. Subdivision of Items
Work under this class is divided into:
- P.1: Cast in-situ piles – bored piles, driven cast in-situ piles, CFA piles.
- P.2: Precast piles – driven concrete piles, steel piles, timber piles.
- P.3: Pile reinforcement – measured separately in tonnes (kg).
- P.4: Pile caps, cut-offs, and trimming.
- P.5: Pile testing – load tests, integrity tests.
- P.6: Ancillary works – temporary casings, drilling mud, bentonite, disposal of arisings.
3. Method of Measurement
- Unit of measurement:
- Length (m) for piles.
- Mass (tonnes/kg) for reinforcement.
- Number (No.) for pile tests.
- Length of pile is measured from cut-off level to toe.
- Extra over items are included for:
- Working in water, temporary casings, bentonite supply/removal.
- Pile splicing or extensions.
- Rock socketing or hard stratum boring.
- Pile testing is always measured separately.
4. Item Coverage
Unless otherwise stated, each pile item shall cover:
- Setting out, positioning, and alignment.
- Supply of pile material (concrete/steel/timber).
- Driving or boring including equipment, handling, placing, and disposal of arisings.
- Temporary casing or liners up to cut-off level.
- Grouting and flushing where applicable.
- Trimming pile heads to cut-off level.
- Site testing of materials.
5. Pile Testing
- Preliminary load tests – separate BOQ items, measured in number.
- Routine load tests – separate items, measured in number.
- Integrity tests (sonic logging, low-strain impact, cross-hole tests).
- Testing costs are not included in pile rate unless specified.
6. Notes for BOQ Preparation
- Clearly state pile type, size, and material.
- Indicate whether temporary casing or bentonite is required.
- Differentiate piles by diameter, length, and ground conditions.
- Specify whether pile toe levels are fixed or variable.
- State whether splicing is anticipated.
- Ensure all testing requirements are itemized.
7. Example BOQ Items
- P.1.1: 600 mm dia bored cast in-situ concrete piles through all strata, up to 20 m depth. Measured per m.
- P.2.1: Precast RCC driven piles, 350 mm sq., including handling and pitching, measured per m.
- P.3.1: Reinforcement for piles, Fe500, measured per tonne.
- P.4.1: Cutting and trimming of pile heads to cut-off level, measured per pile.
- P.5.1: Preliminary pile load test to 2 times working load, measured per test.
- P.5.2: Routine pile load test to 1.5 times working load, measured per test.
