bore pile design bs 8004

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17

Description


Spreadsheet to calculate pile bearing capacity of drilled shaft foundation - bore pile according to BS 8004. For preliminary design purposes, BS 8004 gives presumed bearing values which are the pressures which would normally result in an adequate factor of safety against shear failure for particular soil types, but without consideration of settlement.
Category Types of rocks and soils Presumed bearing value
Non-cohesive soils Dense gravel or dense sand and gravel >600 kN/m²
Medium dense gravel, 
or medium dense sand and gravel
200 to 600 kN/m² 
Loose gravel, or loose sand and gravel  200 kN/m²
Compact sand >300 kN/m²
Medium dense sand 100 to 300 kN/m²
Loose sand 100 kN/m² depends on 
degree of looseness
Cohesive soils Very stiff bolder clays & hard clays 300 to 600 kN/m²
Stiff clays 150 to 300 kN/m² 
Firm clay  75 to 150 kN/m² 
Soft clays and silts  75 kN/m² 
Very soft clay  Not applicable
Peat Not applicable
Made ground Not applicable

Calculation Reference
Reinforced Concrete Design
Design of Footings
ACI 318-08

The calculation of pile bearing capacity for drilled shaft foundation or bore pile, following BS 8004, involves the following steps:

  1. Determine the soil properties, such as the soil type, unit weight, angle of internal friction, and cohesion.
  2. Determine the diameter and length of the pile.
  3. Determine the ultimate bearing capacity of the pile using one of the following methods: a. The static load test, which involves applying a static load to the pile and measuring the deflection and load. b. The dynamic load test, which involves measuring the acceleration of the pile and calculating the ultimate capacity using an empirical formula. c. Analytical methods based on the soil properties and the pile geometry, such as the Schmertmann method or the Broms method.
  4. Calculate the allowable bearing capacity of the pile by applying a factor of safety to the ultimate bearing capacity, typically ranging from 2.0 to 3.0.
  5. Determine the required size and length of the pile based on the allowable bearing capacity and the design loads.

The analysis of pile bearing capacity can be further refined by considering other factors, such as the presence of groundwater, the effect of soil stratification, and the effect of soil consolidation. The analysis can also be performed using computer software or spreadsheet programs, which can provide more accurate and efficient results.

Overall, the calculation of pile bearing capacity for drilled shaft foundation or bore pile, following BS 8004, provides a systematic and reliable approach to design and construct foundations that can support the required loads and ensure the stability and safety of the structures.

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Uploaded
27 Sep 2011
Last Modified
27 Apr 2023
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File Version:
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Rating:
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Comments: 2
hades3 10 years ago
Thanks
JohnDoyle[Admin] 12 years ago
A useful calculation. I have awarded a you a free three month XLC Pro subscription by way of thanks. [Admin]