www.roger-bullivant.co.uk

DYNAMIC LOAD

STATIC LOAD

SONIC INTEGRITY

PILE TESTING

A P P L I C AT I O NDynamic load testing is suitable for all types of pile, but ismost frequently employed on RB pre-cast concrete or tubularsteel driven piles. This method is also ideally suited to smallcontracts, e.g. mini-piles or underpinning, which cannot justifythe relatively large investment of static load testing. Thetechnique determines the load bearing characteristics of thepile including skin friction and end bearing. There arenumerous other parameters which can be determinedincluding pile hammer energy transfer, pile integrity, pilestresses, driving and load displacement behaviour.

D E S C R I P T I O NIn order to dynamically test a pile, the pile must be restruckusing a pile hammer.

Two strain transducers and accelerometers are firmly attachedto the face of the pile near to the head. As the pile is restruckthe equipment measures the force and the acceleration of thepile. This information is relayed to the pile driving analyser,which gives information on the CASE method pile capacity toan experienced test operator. As the test only takes a matterof minutes per pile, a large number can be tested in one sitevisit. Once a series of blows have been struck on the test pile,the data is digitally stored and relayed back to our offices forfurther analysis.

A stress wave analysis is conducted on the data in the RB testdepartment. This includes computer generation of a theoreticalpile and soil model, which is compared with the recorded data.The aim of the method is to produce a model that resemblesas closely as possible that which would be required toreplicate the recorded data. To this end, the model iscontinually updated and altered until the measured data ismatched. Once this has been achieved, the model gives shaftfriction distribution, bearing capacity and load settlementbehaviour, together with additional information as required.

E Q U I P M E N TIn order to carry out this technique, pile driving analyserhardware from Pile Dynamics Incorporated and the modellingprogramme CAPWAP provided by GRL Inc are used. Bothorganisations are responsible for the theories behind thistechnique and are acknowledged as market standard, reliableand accurate procedures.

DYNAMIC LOAD

Pilepreparedfortestingonsite

Piledrivinganalyserforcollectionandanalysisoftest

data

SONIC INTEGRITY DYNAMIC LOAD STATIC LOAD

A P P L I C AT I O NStatic load testing is the method by which the loaddisplacement characteristics of a pile can be determined. Allpiles are suited to testing in this way.

The RB in-house designed and purpose-built static loadtesting frames can accommodate loads of up to 4000 kN.

Additionally, specialist equipment for low headroom orrestricted access locations is available.

D E S C R I P T I O NIn order to apply a known load to the test pile some form ofreaction is necessary. The most commonly used methods arekentledge or tension pile reaction, dependent upon groundconditions. Other methodologies can be adopted according tosite requirements e.g. in areas of restricted access orheadroom.

Once adequate reaction has been provided, the testing iscarried out using a hydraulic jack and calibrated digital loadcell to a previously agreed procedure. Time, load, temperatureand displacement data are usually recorded.

The data is stored electronically for transmission via mobilephone, to RB’s test department for processing. Theinformation is then presented in conventional graphical andtabular format.

E Q U I P M E N TReaction loading frames and kentledge assemblies allow testsof up to 4000kN to be carried out. Measurement of pileresponse to load is measured by digital load cells andelectronic linear variable displacement transducers.

Larger capacity tests can be accommodated on request.

STATIC LOAD

Pilehead measurement at Abingdon, Oxford

Kentledge test-frame on site at Belvedere, South London

SONIC INTEGRITY DYNAMIC LOAD STATIC LOAD

Regional Offices

HEAD OFFICERoger Bullivant LimitedWalton RoadDrakelowBurton-on-TrentStaffs DE15 9UAT 01283 511115F 01283 512233

SCOTLANDT 01259 272050F 01259 272051

NORTH EASTT 0191 5372542F 0191 5193097

YORKSHIRET 01924 224300F 01924 898165

NORTH WESTT 01772 323385F 01772 626814

MIDLANDST 01283 511115F 01283 512233

SOUTH WALEST 01639 895641F 01639 899035

SOUTH WESTT 01373 865012F 01373 865559

SOUTH EASTT 01322 286565F 01322 286566

Roger Bullivant LimitedE: testing@ roger-bullivant.co.uk W: www.roger-bullivant.co.uk

Other Products & Services• Piling

• House Foundations

• Ground Improvement

• Mini-piling

• Underpinning

• Concrete Products

• Conservatory & Extension Bases

APPLICATIONIntegrity testing is primarily used on continuous flight auger (CFA) or RB continuous helicaldisplacement (CHD) and other wet bored piling techniques.

The method is fast and reliable, allowing a large number of piles to be tested in a singlesite visit. The technique is used to determine the reliability, morphology and quality ofconstruction of the piling method.

D E S C R I P T I O NThe pile to be tested must be sufficiently cured, free of latence and trimmed to soundconcrete, preferably to final cut-off level. Using a small hand-held hammer, a series of lowstrain acoustic shock waves are passed down the pile. As it does so, the wave reboundswhere changes in impedance occur. This rebound or echo is then recorded by a smallaccelerometer, held against the pile head. The response is stored digitally and a graphicalrepresentation displayed and plotted, usually against time, for immediate inspection.

E Q U I P M E N TThe sonic testing equipment is supplied by both Pile Dynamics (USA) and TNO-Profound(Holland). They are battery powered and can be operated by one engineer to give anindication of integrity on site.

SONIC INTEGRITY

Sonic

Integrity

testingequipment

ISO 14001 Certificate Number EMS 74925ISO 9001 Certificate Numbers FS 62321& FM 13004