Discover unwanted anomalies with Specialised Pile Integrity Testing

Good workmanship may not always be sufficient. We precisely detect anomalies buried within your pile, in all conditions.

frequency response and pulse echo tests (pile tapping)

Figure 1: Pile Integrity Figure 1
The tests can be implemented on all types of individual cast insitu piles of 250mm diameter and upwards and is a non-intrusive test. The tests are based on locating impedance along the pile shaft by using vibration waves at the top of the pile formed by striking the pile top with an impulse hammer (refer to Figure 1) whilst simultaneously measuring its vibratory response.

When the signal is processed in the time domain the test is called the Sonic Echo Test, and the Frequency Response Test in the frequency domain. The frequency response graph provides the most comprehensive integrity information whilst the sonic echo tests are only used to complement the information obtained from the frequency response tests on selected piles.

These tests have a depth limitation, typically 30 to 35 times pile diameter that are usually dependant on soil conditions. The results are then downloaded and computed in the office, and changes in impedance are related to physical features of the pile, taking into account piling methods, material properties and subsoil conditions.

Prior to carrying out pile tapping the piles will require the following minimum preparation:

  • Piles to be trimmed to sound concrete or grout, with a relatively flat surface perpendicular to the pile axis. Tests can be carried out when piles are being trimmed to final trim level.
  • All loose debris and surface water to be cleaned off.
  • Pile head to be accessible, tests may not be possible with steel in place.
Once an anomaly is identified in the interpretation of the results, further appropriate testing may be carried out. Where practical the pile is exposed at the approximate depth of the anomaly to confirm the findings of the integrity test.

Recently Geosure using the DIAGNOSTIC PILE ANALYSER identified acoustic anomalies in several piles. On an upmarket development in Durban, Geosure were appointed to carry out integrity tests on all piles cast. 25% of the piles tested showed severe necking in the pile’s shaft. These piles were exposed to the depths where acoustic anomalies were identified. The adjacent plates show the severity of some of the anomalies identified.

Pile integrity testing is carried out by Geosure (Pty) Ltd using the Diagnostic Pile Analyser supplied by NDT Technology and, which provides a rapid and relatively inexpensive means of screening groups of piles for anomalies, which might affect pile performance. These tests can be usefully implemented on all types of individual cast in-situ piles. Only limited information may be obtained for secant type piling because of binding between adjacent piles. Precast piles may be checked for mechanical damaged cracks. A pile integrity assessment can only be as good as the quality of the test data. The DIAGNOSTIC PILE ANALYSER is a purpose built system which makes extensive use of the latest digital signal acquisition and data processing techniques to ensure the integrity and quality of the test data. The Analyser has provision to carry out both Frequency and Sonic Echo test methods on each pile. The combination of these methods aids the interpretation of complex results and enables difficult assessments to be made with greater confidence and reliability.


Pile Echo Tester (PET) is a user friendly, highly flexible solution for the testing a large number of deep foundations quickly and accurately. As seen below are the PET equipment. PET is a modular, computer independent system that attaches itself to the USB of regular notebook, tablet PC or Pocket PC via Bluetooth protocol.

Some of the larger projects on which Geosure have carried out pile Integrity testing are:
  • Mhlatuze, Mtunzini and Empangeni Bridges, N2 Upgrade, Durban
  • Oceans Development, Umhlanga, Durban
  • The Arch, Umhlanga, Durban
  • Wilge Bridge, Harrismith
  • New Solar Park, Kathu, Northern Cape
  • Berg River Boulevard Bridge, Paarl, Cape Town
  • N7 Upgrade, Malmesbury, Cape Town
  • Northern Aqueduct Bridge over the Umgeni River, Durban
  • International Convention Centre, Mbabane, Swaziland
  • Zimbali Forest Lodge, Zimbali
  • Maphobeni Bridge, Swaziland
  • Sasol, Secunda
  • Mozel, Mozimbique
  • Western Freeway, Cape Town
  • Port Louis Water Front, Mauritius
  • Dry Dock, Port Louis, Mautitius
  • Thembisa Access Bridge, Gauteng
  • Neptune Interchange, Coega, Port Elizabeth
  • New Institute of Business, Gaborone, Botswana
  • Casino, Bloemfontein
  • Gautrain Rapid Rail Link
  • Port Elizabeth Soccer Stadium
  • Bombela Soccer Stadium
The structural defects in the piles shown in the accompanying photographs were confirmed when exposed by excavation around the pile shafts after anomalies were identified in the integrity test results.

Testing is carried out regularly for the following contractors:
  • Aveng Grinaker
  • China Harbour Engineering Company
  • China Road and Bridge Corporation
  • Dura Soletanche Bachy
  • Frankipile – Keller Group
  • JC Geotechnical Services
  • Megapile Coastal
  • Megapile Inland
  • Pilecon
  • Siyabora Piling
  • Stefanutti Stocks Geotechnical Piling
  • Stefanutti Stocks Geotechnical Piling
  • Wepex Geotechnical
Over the past 20 years Geosure have invested substantial time and effort in developing pile integrity testing skills in South Africa. With the support of NDT Technology in the UK, local personnel have been trained abroad to operate the equipment and evaluate test results. The stature of testing together with the level of skill and experience achieved has established Geosure firmly as the leaders in this field in Southern Africa.

At present it is acknowledged that in South Africa, Geosure has developed and pioneered integrity testing to the point where most piling contractors and many consultants accept the test results with confidence.

The integrity testing service offered by Geosure is considered by many contractors and clients in the marketplace to add significant value to piling contracts, particularly as such testing provides a rapid and relatively inexpensive means of screening the structural integrity of all piles on a site, as opposed to testing a select few piles using pile load tests.
Where acoustic anomalies are identified in test results, further investigation of the piles in question may be required.


Sonic Logging provides a method of assessing the homogeneity of concrete in piles or other mass foundation, such as diaphragm walls. Sonic logging has no inherent limitations on penetration depth of the size or shape of structure, which can be tested. No direct access is required to the concrete surface and the method can be used to test structures with low cut off levels at an early stage. Access tubes have to be cast into the structures to facilitate the tests and pre-selection of units to be tested is therefore necessary.

The tests are directed towards anomalies identified within a group of results, which may warrant further investigation.
For the ultrasonic test at least two tubes, either plastic or steel of minimum diameter 50mm, are cast in the pile (steel tubes are preferable as these are more durable, are less likely to be damaged and less prone to debonding with the concrete). The tubes must be completely filled with water to act as an acoustic coupling agent between the probes and the tube wall. A transmitter of ultrasonic pulses is lowered in one of those tubes and a receiver in another until they reach the base of the pile. Both the transmitter and receiver probes are connected to the CHUM software (a ruggedized pen computer), which records the first arrival time (FAT) and the energy attenuation as the probes are simultaneously raised to the top. As long as the FAT and the energy attenuation are relatively constant, one may deduce that the concrete quality is also uniform and the pile is therefore acceptable.

On the other hand, if at some level there is a noticeable increase in the FAT and / or in the energy attenuation, it means that the concrete at this level is inferior or defective. In such a case, the test may be repeated with the transmitter and receiver at different levels, a technique that enables the determination of both location and extent of the defect (tomography). Consistent transmission characteristics indicate anomalous zones within the sonic transmission profile are immediately obvious and are noted. 

Installing an increased number of tubes on the perimeter gives an almost complete coverage of the pile cross-section. This method of testing is especially suitable for testing large diameter piles. The piles can be tested after the concrete has gained some strength, usually at an age of seven days or more from casting.

Geosure has successfully carried out sonic coring tests on the following projects:

  • A1-M1 Decongestion Project, Mauritius
  • Okavango River Bridge, Shakawe, Maun, Botswana
  • Maputo to Catembe Suspension Bridge, Maputo, Mozambique
  • Dry Bulk Jetty, Richards Bay
  • Mondi Paper Mill, Richards Bay
  • Sonangol Headquarters – Luanda, Angola
  • Dwambazi River Bridge, Malawi
  • Nelson Mandela Bridge in Gauteng
  • Mozal Phase 2 in Mozambique
  • Arabela Sheraton Hotel in Cape Town
  • Bank of Tanzania, Tanzania
  • Mauritius Commercial Bank, Mauritius
  • Berg River Bridge, Franschoek, Cape Town
  • Platinum Toll Highway, Rustenburg
  • Saldahna Bay, Cape Town
  • Langeni Viaduct, Umtata, Eastern Cape
  • Rapid Rail Link Gautrain
  • Sasol Secunda
  • N1 Upgrade, Gauteng
  • Rapid Bus Transit System, City of Cape Town
  • Berth 602 Extension, Port of Cape Town
  • Sicom Building, Port Louis, Mauritius
  • Mt Edgecombe Interchange
  • Grayston Bridge Upgrade



Founded in 1992



throughout South Africa



worked in throughout Africa

SANAS Accredited

Founded in 1992

Responsible engineering for the safety and advancement of our society…

As specialists with industry-leading capabilities and hands-on client service, we work with our clients to create a solid foundation that ensures the integrity and ongoing success of their development.

Founded to ensure the integrity of engineering developments worldwide, Geosure is owned and operated by a team of specialists who as custodians of the environment investigate the earth and problem-solve to provide solutions that create a positive impact for all.

  • Level 1 BEE Rating
  • 2 x SAICE Branch Award Winner for Technical Excellence in Durban
  • 2 permanent laboratories & several on-site satellite laboratories
  • 16 Key Staff

Our Clients

  • AECI
    Durban Chamber of Commerce and Industry
    Ethekwini Municipality
  • Gautrain
    Old Mutual

Our Clients

  • AECI
    Durban Chamber of Commerce and Industry
  • Franki
    Ethekwini Municipality
  • Gautrain
    Old Mutual
  • Tuboseal

Our Services

For almost 30 years we have provided reliable and practical solutions for geotechnical engineering, groundwater supply, hydrogeological modelling and testing of civil engineering materials for both local and international projects.


Geotechnical Investigations


Geotechnical Design


Geohydrological / Groundwater Investigations


Pile Integrity Testing


SANAS Accredited Specialised Geotechnical Testing


On-Site Laboratories

Get In  Touch

    Durban Office

    • 122 Intersite Avenue
      Umgeni Business Park

    Johannesburg Office

    • 44 Andries Street