What is the difference between plate bearing test and CBR test?
CBR tests are carried out on fine materials and plate load tests are done when the underlying materials are coarse. The result of the plate load test gives a CBR equivalent value. We then provide the results to the client to enable them to design any roads and pavements accordingly.
Does CBR relate to bearing capacity?
CBR is a value, not a percentage. It does not correlate well to a bearing capacity other than in a gross classification sense.
What does a CBR test test for?
The California Bearing Ratio or CBR test is performed in construction materials laboratories to evaluate the strength of soil subgrades and base course materials.
What does a plate bearing test tell you?
The Plate Bearing Test (or Plate Loading Test) is an insitu load bearing test of soil used for determining the ultimate bearing capacity of the ground and the likely settlement under a given load. A factor of safety is applied to give the safe bearing capacity of soil.
Why plate load test is required?
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.
What is CBR value of soil?
CBR is the ratio expressed in percentage of force per unit area required to penetrate a soil mass with a standard circular plunger of 50 mm diameter at the rate of 1.25 mm/min to that required for corresponding penetration in a standard material. The ratio is usually determined for penetration of 2.5 and 5 mm .
How do you test a CBR?
How is a CBR Test performed? The CBR test is performed by measuring the pressure required to penetrate a soil sample with a plunger of standard area. The measured pressure is then divided by the pressure required to achieve an equal penetration on a standard crushed rock material.
What is a good California bearing ratio?
California bearing ratio typical values
| General Soil Type | USC Soil Type | CBR Range |
|---|---|---|
| Coarse-grained soils | GW | 40 – 80 |
| GP | 30 – 60 | |
| GM | 20 – 60 | |
| GC | 20 – 40 |
What is CBR test PDF?
The laboratory CBR test consists essentially of preparing a sample of soil in a cylindrical steel mould and then forcing a cylindrical steel plunger, of nominal diameter 50 mm, into the sample at a controlled rate, whilst measuring the force required to penetrate the sample.
What is the procedure of CBR test?
The CBR test is performed by measuring the pressure required to penetrate a soil sample with a plunger of standard area. The measured pressure is then divided by the pressure required to achieve an equal penetration on a standard crushed rock material. The harder the surface, the higher the CBR value.
How do you do a plate bearing test?
The test is usually carried out at foundation level. A load is applied in five increments with readings taken every minute until detectable movement of the plate has stopped. During the test the pressure exerted is added at a consistent rate.
How is CBR test done?
How is California Bearing Ratio ( CBR ) test used?
Also, a fairly accurate California Bearing Ratio (CBR) value can be derived from the sub grade reaction in this test. The Plate Load Test method of CBR testing allows testing over a greater surface area than that of a traditional CBR plunger test, which therefore enables testing of both cohesive and granular material.
Why do you need a plate bearing ratio test?
In some parts, the plate bearing test results may determine the depths of the groundwork that is going to be required. Contrary, CBR method aims at testing the thickness factor that is going to be needed for all materials to be used for construction.
Which is better plate load or CBR test?
The Plate Load Test method of CBR testing allows testing over a greater surface area than that of a traditional CBR plunger test, which therefore enables testing of both cohesive and granular material. Download the infographic explaining the process to determine which test is most suitable.
How are the results of a CBR test derived?
Approximate equivalent CBR values can be derived from the Modulus of sub grade reaction by use of mathematical relationship. Results from the test shall consist of raw data, load-settlement curve, yield pressure, recommended allowable pressure for foundation design, and modulus of subgrade reaction (K) for road design.