Pile tests

This articles is about types of pile tests. It is recommended to read following articles before read this.

· Classification of piles

· Pile machines

Examination and monitoring of the pile construction process should be considered to be of primary importance in any project. Careful observations and accurate records of each pile installation are essential to understand the behavior of completed piles. These records are considered as very important in the test procedures.

Before the start the construction of the project, selected several piles are tested to ensure that it is match with design conditions. By knowing those piles are suitable with particular project and it maintains a better strength, it reduces the risk and wastages.

When our group members visit to site, the pile testing is undertaken within the site. According to their information, there three tests available to do regarding pile testing. They are as follows;

PIT

With this test, can aware whether the pile is bulk or neck pile and about the actual depth of the pile. This test is not done at all the time in pile testing, the decision is up to designer whether test is launched or not.

Dynamic Load testing

Dynamic load testing is the method of predicting the load earning capacity and load deformation characteristic of a pile by measuring its response to the impact of the heavy weight, such as iron driving hammer, striking the head of the pile.

Static Load testing

Static load testing is the direct application of a load to a pile or, more rarely, a pile group, while the deflection of the pile head under the imposed load is measured.

The test load is usually taken to at least the specified working load and often to one and half times or even twice the working load. These are termed proof-loading tests. Trial piles may be loaded to failure (define by a suitable criterion). The load may often be applied in a cyclic manner to investigate the loading and unloading characteristics of pile.

In this test, 1m × 1m × 1m concrete cubes which has 2 Tons weight has been used to make static load on top of the pile. Those concrete cubes have been placed on steel girders, and a hydraulic jack was there in between one of steel girder and surface of top of the pile. When uplifting the cube load by using the jack a load will be apply on the top of the pile. With the applying load pile will sink or go down into the earth.

There three dial gauges to measure the depth of pile would be sink in the earth. Therefore they get three measurements for each trial and get average of those three readings. As well as they examine whether ground level is changed or not with applying load.

First applied 25% of the working designed load of the pile and remain the load as it is within one hour and in every fifteen minutes to fifteen minutes, the readings are taken as above described.

After that 50%, 75% and 100% of the working load apply and continue the same procedure. Thereafter the load is released as applied and keep in and taken readings and also after the reading entire load and took readings as final settlement reading and continue the procedure up to 185% load as shown in the table. We went to the site while they doing this test and the working designed load was 1500 kN/ mm² according to them, with applying the load the 12 mm cube uplift 6 mm. if the readings are beyond the above said, that pile is considered as a failed pile. As the remedy for the failed pile they placed another two more piles by side of that failed pile and put a pile cap as covered all the top of those piles.

Related Articles

· Pile Construction