The initial lateral load test for piles shall be conducted after 28 days of lateral load test pile casting by obtaining a reaction from the concrete blocks or adjacent piles. Sufficient working space should be provided for safety and other arrangements for testing. A horizontal support beam or truss should be fabricated to receive its lateral test load through a horizontal loading platform firmly placed over the compacted ground or adjacent pile, as shown in the picture.
Test Arrangement for Lateral Load Test Pile:
- The reaction load capacity from the loading platform in case of lateral lateral load test pile will be 25% higher considering the factor of safety than the test load.
- For the initial lateral load test for piles, the test load should be 2.5 times of design load, and for the routine lateral load test for piles, the test load equals the working load.
- This reaction load can be achieved through the required number of concrete blocks of size (1.0×1.0x1.0m) with a 2.4 Mt/ block weight or as per the availability.
- All blocks will be placed in such a way so that the stability of the block can be maintained. All elements of providing the reaction shall be designed for 25% of the additional load then the final test load of the pile.
Pile Head Preparation for Lateral Load Test Pile:
- The pile head should be chipped off and removed loose concrete and foreign particle until sound concrete is obtained.
- The projecting reinforcement bar should be cut or bent suitably before Pile head casting.
- Pile head to be cast up to the required level with the same grade of concrete to maintain the natural horizontal plane.
- Steel plate of required radius shall be placed on the curved surface of the finished pile shaft at the Cut-off level.
- Datum bars are to be fixed for lateral load test for piles rigidly to support the dial gauge.
- The support for the datum bar is to be at 0.5m from the face of the lateral lateral load test pile.
- The datum bar shall rest on immovable supports at a distance of 3D from the edge of the test pile, where D is the diameter of the pile.
Dial gauge /LVDT:
- Dial Gauges or LVDTs are used for measuring the lateral lateral load test pile displacement after the application of load.
- The least count of dial gauge shall be at least 0.01mm and resting on the diametrically opposite end of the test pile face.
- For unapproachable pile cut-off levels, displacements shall be recorded with the help of two dial gauges or LVDTs kept vertically 30cm apart from each other of 0.01 mm sensitivity.
- By similar triangles method after interpolating both the reading of dial gauges or LVDTs at pile cut-off level, actual displacement shall be obtained.
- These dial gauge must be set up in such a way that any tilting of the test pile will not cause any error in measurements.
- When the hydraulic jack is placed in between the test pile and reaction pile, one extra dial gauge or LVDT shall be placed on the reaction pile to record the reaction pile displacement.
Lateral Load Test for Piles Procedure:
- Lateral load test for piles shall be done as per IS: 2911, (Part IV) – 2013.
- Arrangement of concrete block can be made as per test arrangement drawing.
- After chipping uneven concrete on the side of the pile, fix a glass piece of size 20 to 30 mm in a square shape to rest the dial gauges tips on the central portion of the glass plate.
- The reaction of load can be taken from the concrete blocks or nearest pile.
- Lateral load test for piles may be carried out by introducing a hydraulic jack with a power pack between the pile and the horizontal support beam or truss.
- The load increment for lateral load test pile should be 20% of the estimated safe lateral load.
- Further increment should be applied after the rate of displacement is less than or equal to 0.1mm per 30 minutes, subjected to a minimum of 30 minutes.
- The required number of incremental loads will be applied as per the test requirement.
- Hydraulic jack of required capacity will be used along with calibrated pressure gauge having least count 20kg/cm2. However, we have to keep an additional pressure gauge of the same least count for standby.
- After reaching full load condition, we have to maintain the load for 24 hours, and observation will be recorded every hour.
- After 24 hrs of observation, we have to unload the applied load gradually in reverse order of applied load.
- There must be some rebound, and the final reading will be recorded.
Interpretation of Result:
Safe Lateral Load:
As per IS 2911 (Part 4): 2013, For both free head and fixed head, the safe lateral load on the pile for the initial test shall be taken as the least of the following:
- 50% of the final load at which the total displacement increases to 12 millimetres.
- Final load at which the total displacement corresponds to 5 millimetres.
- As per performance or design requirements, load corresponding to any other specified displacement.
Test and Records:
- The pile test data shall be suitably presented by the curve drawn between; Load Vs Settlement and Time Vs settlement for each loading.
Considering proper safety care shall be taken to ensure the correct implication of the working procedures described in this method statement.