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Concrete NDT · Deep Foundations

Pile Integrity
Testing

Sonic Echo / Impulse Response PIT for bridges, piers, jetties, towers and building foundations — depth, geometry and structural condition from the surface.

ASTM D5882
Standard
AS 2159
Standard
Non-Invasive
Surface Access Only

Sonic Echo &
Impulse Response

Pile Integrity Testing (PIT) is conducted in accordance with ASTM D5882-16 and AS 2159-2009, covering testing procedures, data acquisition, processing and reporting. It is applicable to the investigation of deep foundation structures including bridges, piers, jetties, towers and buildings.

A compression or tension wave is introduced at the pile head by a hand-held hammer. The wave travels through the shaft and is reflected when it encounters a change in acoustic impedance — caused by a change in cross-section, material quality, or the pile toe. A sensor at the pile head records the return signal.

This method effectively and accurately determines pile depth, geometry and structural condition — making it a reliable tool for both assessing unknown existing foundations and for quality verification of ongoing piling works.

Wave Propagation Principle
Pile head — impact & sensor
↓ Wave propagates downward
Impedance change — defect / neck
↑ Reflection returns to sensor
Pile toe — terminal reflection
Sound piles produce a distinct toe reflection with minor amplitude variation between impact and return
Defects produce early reflections before the toe — amplitude and polarity indicate severity and type
Negative velocity reflections indicate bulging — caused by auger wobble or excess grout pressure increasing shaft diameter

What PIT
Resolves

From a single hammer impact at the pile head, the reflected waveform yields a complete structural picture of the shaft — geometry, depth and any discontinuities along its length.

Geometry
Necking & Bulbing

Reductions (necking) and increases (bulbing) in shaft cross-section detected from reflection polarity and amplitude. Depth estimated from wave travel time and assumed velocity.

Integrity
Cracks & Discontinuities

Horizontal cracks, cold joints and material defects generate strong reflections. Discontinuities in concrete quality — soft inclusions, soil intrusion, segregation — are also detectable as impedance anomalies.

Depth
Depth to Defect & Toe

Travel time of the reflection and the known or assumed wave velocity in concrete give depth to any anomaly and to the pile toe — enabling comparison with design drawings and as-built records.

Variation
Size & Material Changes

Changes in pile diameter or material properties (e.g. transition from concrete to rock socket) are mapped with depth — particularly valuable for unknown or undocumented legacy foundations.

Dynamic Response
Pile Head Stiffness

Impulse response analysis yields pile head stiffness (kN/mm) — a dynamic foundation parameter used in structure–soil interaction modelling and for comparing piles within a group.

Frequency Domain
Shaft Mobility

Frequency-domain analysis of the shaft mobility curve identifies resonance peaks corresponding to pile length and detects major cross-section changes that are subtle in the time-domain trace.

Bridges · Jetties
Piers · Buildings

PIT is equally applicable to new construction QA/QC and to condition assessment of unknown or aging deep foundations — delivering actionable intelligence without excavation or coring.

Request PIT Survey Structural Integrity

Five-Grade
Integrity Rating System

The reliability of defect identification and depth estimation depends on the accuracy of wave velocity determination and the overall quality of the pile. All piles are classified using a standardised five-grade system, ensuring defensible and consistent reporting across a foundation program.

Each classification carries defined reporting language, enabling clear communication between testing, engineering and project management teams — and straightforward integration with remediation planning.

Classification is conducted in accordance with ASTM D5882-16 and AS 2159-2009 — covering testing procedures, data acquisition, signal processing, interpretation and formal reporting.

AA
Sound Integrity

Clear toe reflection observed, indicating sound shaft integrity within the accuracy limits of the design length and assumed wave velocity. No remedial action required.

BB
No Significant Anomaly

No indication of major defects. No reflections associated with pile geometry changes, material defects, or a clear toe response are observed. Minor signal features within acceptable limits.

ABx
Limited Interpretation Depth

No major defects indicated to depth x (m). Full-length interpretation is not possible due to PIT limitations — caused by factors such as a large shaft bulge, high surrounding soil resistance, or excessive pile length. Supplementary testing may be warranted.

PFx
Probable Flaw

A reflection indicating a probable flaw at approximate depth x (m), typically associated with an unplanned reduction in pile size or material quality. A toe reflection is still apparent below the anomaly. Engineering review recommended.

PDx
Probable Defect

A strong reflection indicating a probable defect at approximate depth x (m), caused by a significant reduction in pile cross-section or a major material defect. Immediate engineering investigation and possible pile replacement or remediation.

New Works &
Existing Foundations

PIT delivers value at two distinct project phases — quality assurance during piling works, and condition assessment for aging or undocumented foundations.

New Construction
  • QA/QC verification of driven and bored piles
  • Detection of construction defects before concrete curing
  • Sampling-based testing across large pile groups
  • Verification of design pile length achieved
Existing Structures
  • Condition assessment of bridges, jetties and wharves
  • Unknown pile length determination
  • Pre-purchase and insurance evaluations
  • Post-event assessment (flood, earthquake, overload)

Clear, Standardised
Reporting

Each pile tested is reported with its waveform trace, interpreted classification, and depth estimates — in a format suitable for direct submission to structural engineers and regulatory bodies.

PIT Report Contents
ItemDetail
Pile registerID, location, design dimensions and test date for every pile tested
Velocity tracesTime-domain waveform for each pile — impact, reflections and toe response annotated
Frequency plotsMobility spectrum where Impulse Response analysis is applied
Depth estimatesCalculated depth to anomaly and pile toe, based on calibrated wave velocity
Classification tableAA / BB / ABx / PFx / PDx rating per pile with supporting commentary
Plan layoutClassification colour-mapped onto foundation plan for rapid visual review
RecommendationsEngineering action items for each PFx and PDx classified pile
Structural Integrity Corrosion Testing Visual Inspection Request PIT Survey

Areas We
Serve in Tasmania

Spaulding Geophysics provides pile integrity testing across Tasmania, from Hobart and Launceston to regional centres, coastal towns, and remote communities statewide.

South & Greater Hobart
  • Hobart
  • Kingston
  • Margate
  • Kettering
  • Bruny Island
  • New Norfolk
  • Sorell
  • Dodges Ferry
North & Launceston
  • Launceston
  • George Town
  • Longford
  • Perth
  • Hadspen
  • Westbury
  • Deloraine
  • Bridport
Northwest Coast
  • Devonport
  • Burnie
  • Ulverstone
  • Wynyard
  • Penguin
  • Smithton
  • Latrobe
  • Port Sorell
East Coast & Midlands
  • Bicheno
  • St Helens
  • Scottsdale
  • Swansea
  • Campbell Town
  • Ross
  • Queenstown
  • Huonville

Spaulding Geophysics delivers pile integrity testing across all of Tasmania — including Hobart, Launceston, Devonport, Burnie, Ulverstone, George Town, Longford, Deloraine, Smithton, Wynyard, Bicheno, St Helens, Scottsdale, Queenstown, Huonville, Kingston, Kettering, Bruny Island and surrounding communities. Remote and regional sites welcomed.