The Plate Load test is a field test used to determine the deformation characteristics, bearing capacity and Modulus of Subgrade Reaction of the ground. Quick and easy to apply, the plate loading test checks the bearing capacity and settlement of foundation soil and substrate. It is used to ensure safe design and quality control.
This information can be used to design shallow foundations such as rafts and footings. The test is carried out by imposing a load on to the surface or near-surface of ground at a specified location and measuring the induced settlement.
Technician will setup high precision instruments for the purposes of accurately measuring the imposed loading as well as resultant ground settlement. The results are thereafter processed and presented in report form for use by engineers.
The test applies a vertical load to a variety of specialist, steel bearing plates, measuring the penetration to determine the degree of compaction of back-fill, under-foundation or foundation soil, sand or stone.
Because it can be applied to thin soil layers, the test is mainly used in the construction of roads, airstrips and embankments or in the calculation of floor slabs.
The vertical load on the plate is applied using a hydraulic jack and counterweight. The resulting surface deflection or penetration of the plate is read after stabilization at three points spread over 120 degrees from a fixed frame. The average deflection is calculated and this allows the determination of the compression modulus or the modulus of subgrade reaction and spring constant.
The plate loading test can be used in conjunction with other geotechnical tests to gain an accurate picture of soil properties.
The plate load test is a field test, which is performed to determine the ultimate bearing capacity of the soil and the probable settlement under a given load. This test is very popular for the selection and design of the shallow foundation.
For performing this test, the plate is placed at the desired depth, then the load is applied gradually and the settlement for each increment of the load is recorded. At one point a settlement occurs at a rapid rate, the total load up to that point is calculated and divided by the area of the plate to determine the ultimate bearing capacity of soil at that depth. The ultimate bearing capacity is then divided by a safety factor (typically 2.5~3) to determine the safe bearing capacity.