Submission of Amendment and Record Piling Plans
Introduction
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This guideline outlines what constitute material and immaterial changes in piling works. Immaterial changes are to be incorporated in the record plans whereas material changes require submission of amendment piling plans for approval before construction.
Amendment Plans
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The Building Control Regulations require that where it is desired that any building works deviate from the approved plans of the building works, and if the deviations involve material changes, the Qualified Person (QP) shall submit amendment plans of the building works to BCA for approval before construction.
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"material changes", in relation to building works, is defined in the Regulations as any changes that affect the key structural elements of the structure to such an extent as to require a re-design of the key structural elements.
Record Plans
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Where the deviations involve immaterial changes, there is no need to obtain prior approval from BCA before construction. The QP shall only be required to prepare and submitto BCA, on completion of the building works, record plans showing all the immaterial changes, together with the appropriate certificates.
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"immaterial changes", in relation to building works, is defined as any changes that either do not affect any key structural elements or that affect the key structural elements but the effects are localised in nature and do not require a re-design of the key structural elements.
What constitute material changes in piling works
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Any material change in piling works will require amendment piling plans to be submitted before construction works on the piling works that have deviated from the approved plan are carried out.
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Deviations from the approved plans for piling works which are considered as material changes will include the following instances:
- Table 1 summarises the instances which are deemed as involving material changes to the piling works.
Table 1 - Material changes to the piling works
| Type of piling system |
Adopted Design Criteria |
What constitutes Material Changes |
| All types |
Allowable pile capacity
Load on piles |
Any change in the load on piles resulting from major changes in the design of structure that are to be supported by the piles. |
Cast In-situ Bored Piles
Barrette Piles
Diaphragm Walls or Contiguous Bored Pile Walls which act as load bearing structures |
Unit Skin Friction
Unit End Bearing |
Any change in the adopted design criteria |
Unit Skin Friction
Unit End Bearing
Pile Embedment Length into Competent Rock |
Any change in any of the adopted design criteria;
or
Any reduction in embedment length into competent rock |
| Percussion Piles |
Pile Length
Pile Set Criteria |
A lower pile set criterion on site (e.g. larger final pile penetration per blow or larger temporary elastic compression);
or
A lower driving energy used;
or
A reduction of more than 20% in pile length or any other reduction in length which is assessed by QP to be critical to affect the allowable pile capacity. |
| Jack-in Piles |
Pile Length
Pile Termination Criteria |
A lower pile termination criterion on site (e.g. lower jack-in load or shorter duration for the application of jack-in load);
or
A reduction of more than 20% in pile length or any other reduction in length which is assessed by QP to be critical to affect the allowable pile capacity. |
What constitute immaterial changes in piling works
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Departure or deviations involving immaterial changes to the approved piling plans should be compiled and shown in the record piling plans which are to be submitted on completion of the piling works
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Examples of immaterial changes captured in the Record Piling Plans include–
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The details to be incorporated in the Record Piling Plans include the following–
The qualified person must ensure that the relevant construction tests in connection with the building works as described in section 7 of the Building Control Act are carried out. The following documents are to be submitted:
Forms
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Form BCA-BE-QPCTPW (BEV/C1) [Certificate of Supervision of Piling Works and Notice of Completion By the Qualified Person for Structural] and BCA-BE-CTASST (BEV/C3) [Submission Certificate of Record Structural Plans/Calculations] are to be submitted together with the record piling plans, showing the pile penetration length, pile set (for driven piles), the location and type of pile load tests, within 28 days of completion of piling works.
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Form BCA-BE-QPCTPW (BEV/C1) [Certificate of Supervision of Piling Works and Notice of Completion By the Qualified Person for Structural] is to be endorsed by the QP appointed under section 8(1)(b) or 11(1)(d)(ii) of the Building Control Act.
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Form BCA-BE-CTASST (BEV/C3) is to be endorsed by the QP appointed under section 8(1)(a) or 11(1)(d)(i) of the Building Control Act. Either paragraph (a) or (b) in Form BCA-BE-CTASST (BEV/C3) is to be deleted.
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Records of piles eccentricities and calculations (if necessary) are to be submitted before commencement of basement floor or 1st storey floor, whichever is earlier.
Record Piling Plans
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All plans are to be clear and legible.
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All plans are to be endorsed by both the QP appointed under section 8(1)(a) or 11(1)(d)(i) of the Building Control Act and AC (if applicable), and bear the standard endorsement and Regulations 18(3)(b) and 18(3)(c) (if applicable) of the Building Control Regulations on the first and last sheet of the plans. [refer to section on Endorsement by QP and AC]
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The total number of plans, sheet no. and project reference no. are to be indicated on all plans.
Calculations (if necessary)
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All calculations are to be endorsed by the QP appointed under section 8(1)(a) or 11(1)(d)(i) of the Building Control Act and AC (if applicable), and bear the standard endorsement and Regulations 18(3)(b) and 18(3)(c) (if applicable) of the Building Control Regulations on the first and last sheet of calculations. [refer to section on Endorsement by QP and AC]