Conformance is the measure of quality, hence quality requirements should be clear and verifiable so that they are easily understood by all parties. Dutch Foundation puts into practice an effective quality control system implemented by qualified engineers to observe, monitor, verify and inspect all definable features of work on a project in order to assure conformance.
Quality and Inspection and Testing Plans are developed specifically for each project to encompass all project quality assurance requirements. Experienced test technicians are directly involved in all testing operations, while an alert team of quality control engineers observe and ensure that all test setups, piling operations and activities comply with project requirements. Comprehensive piling records are punctually completed, reviewed for accuracy and filed by the quality assurance department.
According to project requirements, various tests, measurements and inspections are conducted to ensure the integrity and reliability of the constructed piles. Material tests are performed on concrete, its constituents and on steel to be used for the fabrication of the reinforcement cages. All finished piles are inspected for verticality and location and tested for integrity. A percentage of all other piles are subjected to other types of testing as required.
Dutch Foundation performs all static load tests and inspections in witness of the consultant representative and the expert assistance of a third party when and if required. A qualified, certified and approved third party performs all other material and pile tests.
The sampling frequencies for these tests are determined by the project specifications or by referenced standards. All required testing is clearly identified and listed in the project Inspection and Testing Plan for ease of reference and control.
Concrete constituents are tested to ensure conformance to project specifications.
A trial mix is routinely made for testing purposes to ensure that proposed mix designs meet requirements.
In addition to supplying mill certificates for all deformed steel rebar to be used for the fabrication of reinforcement cage, batches are also tested.
STATIC LOAD TESTING
Static load test (SLT) is the most reliable method of determining pile load capacity. It is the most fundamental form of pile load test and is considered as the bench-mark of pile performance. It involves the direct measurement of pile head displacement in response to a physically applied test load. Testing a pile to failure provides valuable information to the design engineer and is recommended for load tests performed prior to the foundation design or working piles construction. This method is applicable to all types of piles regardless of their method of installation.
PILE INTEGRITY TESTING
PULSE ECHO TEST
The Pulse Echo Test, also known as Pile Integrity Test, Sonic Echo Test and Low Strain Impact Integrity Test, is a rapid, inexpensive, non-destructive method to check for pile defects such as voids, cracks, necking, inclusions, etc. It determines the pile integrity, dimensions, continuity and pile material consistency.
TRANSIENT DYNAMIC RESPONSE
Transient Dynamic Response (TDR) method is a low strain dynamic test which provides a rapid and accurate way of assessing the continuity and integrity of concrete pile foundations.
HIGH STRAIN DYNAMIC TEST
The basic purpose of this test is to evaluate pile static capacity, its structural integrity as well as hammer performance, pile stresses and soil characteristics, such as soil damping coefficients. On-site evaluation of the test results by a trained and experienced professional would determine if the pile is to be accepted or rejected.
Caliper logging of boreholes is commonly conducted to measure variations in borehole diameter over the length of the excavation. Information of borehole diameter, shape and roughness can be used to calculate borehole volume.
CROSS-HOLE SONIC LOGGING
Cross-Hole Sonic Logging (CSL) allows for the detection of concrete defects such as poor quality concrete, soil inclusions, voids, honeycombing and slurry inclusions. This method is applicable to piles of any dimensions and can be used on diaphragm wall or any similar concrete structures. It gives indications of the concrete quality down the entire pile shaft; it does not however provide information about the concrete outside the reinforcement cage and does not clearly identify the type of detected defect.