Unit Overview
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P2
P3
P4
P5
P6
P7
P8
M1
M2
M3
D1
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Traditional Cavity Wall and Strip Foundation
Raft Foundations and Timber Frame Construction

P4 - Methods of Digging Foundations

Criteria

explain the methods used to construct different types of foundation

 

Task

Produce method statements for the three types of foundation listed in P3.

 

 

A method statement is a document that the construction company normally supply the client with, it details how the various parts of the construction will be carried out.

 

Click for an example of a method statement

 

You need only produce a bullet point list for each of the foundation types and much of the work will be similar for each type of foundation. These are some of the things you will need to consider.

 

  1. How will the area to be dug be marked out?
  2. What will you use to dig out the soil?
  3. What will happen to the soil you are digging out?
  4. How will you stop people falling in the trench?
  5. How will you stop the trench collapsing?
  6. How will you remove water from the trench or hole?
  7. What is materials being put in the trench or hole to form the foundations?
  8. How will concrete be moved around?
  9. Who will supervise or make sure everything is going to plan?

 

pilingsstrip foundations

 

 

Piled Foundations

Piled Foundations

 

 

 

 

 

  1. Site made secure – HASAWA – Fencing
  2. Location of underground services established – existing records, trial pits, CAT scan
  3. Pile locations marked out – need for accuracy, theodolite, surveying pegs
  4. Pile driver on site – control of work around plant, banksman, warning signs
  5. Dig surface with auger to small depth – check location by measuring to edge of auger.
  6. Lift auger out of hole while not turning, deposit subsoil appropriately. Helical coil means soil can be lifted out of hole. Flight cleaning wheel helps clear soil.
  7. Repeat till at required depth – more sections added to shaft of auger if required – dpeth is that of firm load bearing soil.
  8. Steel casement inserted by crane and vibration hammer if required - sidewall support.
  9. Concrete inserted, modern pile rigs use a hollow auger to pump concrete to base of hole, reduces the risk of side wall collapse.
  10. Steel casement removed.
  11. Steel cage lowered into wet concrete, pushed down by vibration hammer or excavator.
  12. Steel rebar to link to pile cap inserted while concrete is wet.
  13. Concrete left to cure 5 days min.

Pile Foundation Class Notes