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The goal of integrity testing is to find such defects before they cause any harm. Direct approaches were used in the past to investigate pile integrity. External approaches like excavating around the pile and interior or intrusive procedures like core-drilling were among them. Pile testing is done on a regular basis to ensure that the design and construction of the piles meet expectations, or to aid in the design of piles prior to the major piling construction works.
There are two types of pile testing:
Integrity tests indicate the soundness of concrete, but they should only be performed by those who are familiar with the process and who are capable of interpreting the results with relation to piling. A small metal / hard rubber hammer is used to lightly tap the top of the pile during a pile integrity test.
Static load testing involves gradually loading the pile using reaction piles, surface footings or kentledge via a load cell. This type of testing is widely regarded as the most reliable for testing heaps since it most nearly reflects the piles' operational loading circumstances.
The force required to induce a pile to pierce the ground at a steady rate is monitored in the CRP test until either the maximum specified test load is reached or the pile fails. The test takes less than 24 hours to complete, discounting the time spent assembling and removing the test equipment.
The deflection of the pile butt under the test load is usually the most fundamental information to be derived from a pile load test. Reading a target rod (or scale fixed to the pile) with an engineer's transit referenced to a set benchmark is perhaps the most basic technique of measuring pile butt movement. In most circumstances, the level of precision produced with this apparatus is adequate. Measurements with the level and rod (or scale) are frequently used as a supplementary or backup system to verify the accuracy of other measuring techniques.
The mirror, scale, and wire approach can be used to get direct readings of the pile butt movement (vertically or horizontally). A measuring scale is mounted to a mirror, which is then attached to the pile or test plate directly. Direct readings of pile movement are possible thanks to a taut wire passing in front of the scale. By matching the wire and its image in the mirror, consistent scale readings can be produced. A weight and pulley system or springs can keep the wire taut.
Dial extensometers installed on an independent support system with gauge stems bearing on the top of the test plate or on angle irons affixed to the pile's sides are the most frequent way for measuring pile movement (Fig. 3). To compensate for possible tilting or lateral movement of the pile under load, at least two dial gauges located on opposite sides of the pile should be employed.
Gages with a sensitivity of 0.001 in. are sometimes specified, but most gauges with a reading of 0.01 in. provide enough precision to meet the conventional settlement conditions. Some of the standard requirements, such as until settlement stops, are typically impossible to meet with ultra-sensitive dial gauges.
It is common practice to attach dial gauges to monitor lateral movements of the pile under test when the apparatus for a compression test is set up. This movement could be caused by eccentric loading and contribute to the pile butte's apparent vertical movement.
The instrumentation system must be supported separately from the loading system, with supports protected against extreme temperature changes, test load effects, and test staff disturbance. It is advisable to have a secondary or backup instrumentation system in case the primary system is accidentally disrupted or if dial gauges need to be reset in order to ensure data continuity.
Installing strain rods or gauges causes a physical change in the cross-section of the pile, which affects its elastic properties. Although data at numerous intervals along the pile shaft is preferable, for the sake of practicality, it is occasionally necessary to sacrifice some data. A single strain rod to the pile tip can often provide all of the necessary information on the pile's elastic behaviour and basic load distribution.
“Concrete piles are subjected to sonic integrity testing (SIT). It means a low strain integrity test is frequently performed immediately after pile driving or within days of the installation of cast-in-situ piles to assess pile quality. Sonic Integrity Assessing is a common method for non-destructively testing the value of concrete piles before they are integrated into the definitive foundation plan.
The Profound SIT series answers the requirement for specialized Sonic Integrity Testing of concrete piles in the construction industry. After installation, the Profound SIT series can verify pile length and assess the soundness of foundation piles for flaws. Testing can reveal which heaps need to be investigated further
The SIT series are constructed for field use as well as innovative explanation and data management in the office. The SIT models are built to last, are conveniently transportable, and are simple to use on the job site. A single individual can test a large number of stacks in an hour. Request more information from Profound by clicking here. Characteristics.
In-field user-friendliness: each SIT includes a hammer, an acceleration sensor, cables, and a reliable data gathering and signal processing unit with a full-colour display. The SIT and its accessories can be readily transported thanks to the sturdy, weather-resistant case.
The SIT system displays the measurement signal directly on the full-colour screen, allowing users to double-check that tests were completed successfully on the spot. The number of signals stored per pile is entirely up to the user.
In a typical static axial deep foundation load test, a force is applied slowly against an independent reaction to simulate structural loading. It's the most dependable way to figure out how well a pile will perform under ordinary service conditions. The main drawbacks of this testing are
(1) the high costs of set-up, testing, interpretation, and construction delays, and
(2) the inability to gather information regarding the pile-soil interaction along with the pile without additional testing.
When high-capacity foundations are involved, these limits become even more evident.
I hope the blog provides you with a sound understanding of Pile Load Testing and its purpose.
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