IS 2911 PART (IV)
AXIAL COMPRESSION TEST WITH KENTLEDGE BLOCKS
Load Test shall be performed when concrete has reached its required strength i.e. 28 days strength. The axial compressive loads test should be done as per IS code 2911 part IV (latest revision). Pile Loading Test shall be performed by applying compression load to the pile top by means of a hydraulic jack against rolled steel joist (RSJ) or suitable frame capable of providing reaction and the settlement shall be recorded by suitably positioned dial gauges. The Kentledge consisting of RSJ or frame capable of providing reaction shall be used. The dead weight to be applied shall be 25% more than the maximum jacking force required. The C.G. of kentledge should be on the axis of the pile and the load applied by the jack should be co-axial with the pile.
VERTICAL LOAD TEST USING SAND PACKS
The test can be initial or routine test .The load is applied in increments of 20% of the estimated safe load. Hence the failure load is reached in 8-10 increments. Settlement is recorded for each 45 Settlement is recorded for each increment until the rate of settlement is less than 0.1 mm/hr. The ultimate load is said to have reached when the final settlement is more than 10% of the diameter of pile or the settlement keeps on increasing at constant load. After reaching ultimate load, the load is released in decrements of 1/6th of the total load and recovery is measured until full rebound is established and next unload is done. 46 After final unload the settlement is measured for 24 hrs to estimate full elastic recovery. Load settlement curve depends on the type of pile.
LATERAL LOAD TEST
When performing lateral load tests on deep foundations, it is desirable to obtain horizontal displacement versus depth profiles. These profiles can be used in conjunction with lateral load versus displacement curves to calibrate lateral pile analysis programs. In addition, the displacement versus depth curves can be used to determine bending moment versus depth profiles. Horizontal displacement versus depth profiles have typically been determined using inclinometer probes or strings of downhole inclinometers. Inclinometer probes require the user to measure slope at 0.6 m intervals within a special grooved pipe which is typically concreted into place within the pile. The displacement of the pile must be held constant over a 15 to 20 minute period while the inclinometer measurements are made.
PULL OUT TEST
This test method covers determination of the pullout strength of hardened concrete by measuring the force required to pull an embedded metal insert and the attached concrete fragment from a concrete test specimen or structure. The insert is either cast into fresh concrete or installed in hardened concrete. This test method does not provide statistical procedures to estimate other strength properties.
A jack is a device that uses force to lift heavy loads. The primary mechanism with which force is applied varies, depending on the specific type of jack, but is typically a screw thread or a hydraulic cylinder. Jacks can be categorized based on the type of force they employ: mechanical or hydraulic. Mechanical jacks, such as car jacks and house jacks, lift heavy equipment and are rated based on lifting capacity (for example, the number of tons they can lift). Hydraulic jacks tend to be stronger and can lift heavier loads higher, and include bottle jacks and floor jacks.
Dial indicators are one of the primary measuring tools used in precision engine building. They are typically used to measure deck clearances, crankshaft thrust and straightness, lifter travel and other measurements that involve the distance between two surfaces or small amounts of component travel. Dial indicators typically measure ranges from 0.25mm to 300mm (0.015in to 12.0in), with graduations of 0.001mm to 0.01mm (metric) or 0.00005in to 0.001in (imperial/customary).
Many techniques have been developed for the measurement of pressure and vacuum. Instruments used to measure pressure are called pressure gauges or vacuum gauges. A pressure gauge is used to measure the pressure in a vacuum—which is further divided into two subcategories: high and low vacuum (and sometimes ultra-high vacuum). The applicable pressure ranges of many of the techniques used to measure vacuums have an overlap. Hence, by combining several different types of gauge, it is possible to measure system pressure continuously from 10 mbar down to 10-11 mbar.
The Pile Integrity Tester gives peace of mind that a pile or shaft is free of major cracks and voids, prior to construction of the superstructure. It may be used on most concrete or wood foundations. The PIT may also be used to test pile integral in the structure, such as those supporting existing bridges or towers, and may assess their length. The PIT performs wave equation-based non-destructive foundation investigation known as low strain impact integrity tests or low strain dynamic tests. These tests may be performed by the pulse echo or transient response methods.