Pile Integrity Testing

Temeltek Engineering LLC. provides pile integrity testing for the clients who need engineering support for their installed piles no matter what the nature of issue and the type of the piles. Furthermore, Temeltek Engineering LLC. is an authorized commissioning company when a third party commission of the installed entities is required. There are several reasons why you may need Temeltek’s integrity testing. majority of cast-in-situ pile fails for various reasons as ;

• • • Defective pile shaft necking,
    • Intrusion of foreign matters
    • Improper toe formation due to contamination of concrete at base with soil particles,
    • Discontinuity of concrete,
    • Leaching of concrete due to high water current,
    • Improper construction method,
    • Poor quality control of concreting etc.

    The quality of the testing and acquiring a true report for the piles is so significant. Cracks are developed during handling operation of precast concrete piles, this may also lead to failure of precast concrete piles. So, in order  to ensure the proper placement of piles, its strength and durability, Temeltek’s will be next to you for  pile integration test which  is conducted before completion of pile caps. The integration test of piles assures proper functioning of pile foundations without failure.

    So what is Pile Integrity Testing (PIT)? Pile Integrity Testing (PIT)  is a low-strain and non-destructive integrity test method which is applied with the impact from a small hand-held hammer. This low-strain test can be applied to any concrete piles as the following;

    • Pre-stressed concrete piles
    • Drilled Shafts
    • Auger Cast Piles,
    • Concrete Filled Pipe Piles

    The impact of the small hand held hammer generates acceleration and stress waves and this is the input of the Pile Integrity Testing. (PIT). A stress wave (compression / tension)  in a uniform rod is reflected if the wave encounters an impedance change based on stress wave propagation and reflection theory. Structurally sound shafts made with concrete should have reflection wave from shaft toe with only minor variations of the record amplitudes between impact and toe reflection.  Sound shafts may also be indicated by negative velocity reflections which are often caused by bulges (softer soils), auger-wobble or excess grout pressure allow for an enlargement of the bored hole.

    Pile Integrity Testing Assessment Categories

    It will generally indicate that the shaft integrity is acceptable, if the toe reflection is observed, However, it is difficult to draw conclusions regarding the length of shaft or the integrity of the entire shaft when shaft material has a high resistance; or the shaft is relatively long compare to its diameter; or the shaft has numerous cross-sectional changes, Test shafts can be categorized into one of the following categories:

    AA: Sound shaft integrity indicated; a clear toe reflection can be identified corresponding to the reported length and wave speed within an acceptable range.

    BB: No major defect indicated; the records indicate neither reflections from unexpected significant reduction of pile size or material quality nor a clear toe response. In this case, there is no indication of major deficiency.

    ABx: No major defect indicated to a depth of x (m); due to the limitation of PIT, interpretation of the full length is not possible. A large bulge or high soil resistance may cause the shafts fall into this category.

    PFx: Indication of a probable flaw at approximate depth of x (m); at least one reflection corresponding to an unplanned reduction of size or material quality and toe relection is apparent.

    PDx: Indication of a probable defect at an approximate depth of x (m); a major reduction of size or material cause a strong reflection in the PIT records and toe reflection can not be located.

    IR: Inconclusive record; PIT data is unable to be interpreted caused by the following reasons:

    < poor pile or shaft top quality (concrete curing period too short)

    < Joints or planned caisson diameter changes which prevent toe signal identification

    Pile Integrity Testing Limitations

    PIT testing method is limited to shaft integrity assessment of major shaft defects or material quality changes. The location of the defect is only as accurate as our knowledge of applicable wave speeds. PIT test results should not be the only means for checking the quality of foundations. Field installation observations including grout or concrete volume and analysis of standard geotechnical borings,should be included in the foundation evaluation process.

    Advantages

    • Defects can be discovered at an early stage and remedial work undertaken.
    • Testing can be carried out on any accessible pile.
    • The method is quick and economical.
    • A large number of piles can be tested in a single day (up to 200 piles dependant upon pile head access and adequate pile head preparation).