Hixtra Ltd 
Construction & Geotechnical Testing 
We carry these out all over the UK. Whether it's for CBR values, Crane or Pile Mat testing or for geotechnical analysis we have it covered. 
Here at Hixtra we are UKAS accredited, trained and equipped to carry out a range of plate bearing tests to suit a variety of materials and site conditions for whatever reason you need them for. Plate size, loading cycles, unloading cycles, mass of reaction load, accuracy of measurement, site restrictions, height restrictions, number of tests - we can advise on it all to make sure you get value for money, and the exact test method you need to simply and quickly evaluate your material. 
We offer four plate sizes; 300mm, 450mm, 600mm and 760mm diameter, one of which should be a match for your testing needs. 
 
In the geotechnical world, an agreed rule of thumb is that during the test a depth of material approximately twice the plate diameter will be stressed, so it’s important to know what depth you want this zone of influence to be for your testing. 

Plate size: An important choice 

A question that is often discussed with users of plate bearing tests is what plate size do I need for my testing? As usual for soils and geotechnical testing the answer is never straightforward as it is often material dependent! 
For the selection of plate size - common sizes are 300mm, 450mm and 600mm diameter - a few things need to be considered such as: 
Will the mass of the construction plant I provide as a reaction load for the test be sufficient to provide the stress on the plate that I need? 
 
How thick is the material that I want tested? 
 
What kind of depth do I want the zone of influence of the test to extend to? 
 
What is the approximate maximum particle size of the material I want tested? 
 
Is my testing to obtain a CBR value, or to measure settlement under a specific load, such as for testing the ground underneath crane pads or pile mats? 
 
Don’t worry though, as experts in this type of testing we can sort all of this out for you quickly, efficiently and prior to testing to make sure you get exactly what you need. It’s all part of our service. 

Reaction Load 

It is usually the case that a reaction load, normally in the form of some construction plant, would be provided to carry out the site based testing. 
Obviously there are many different types of plant, so at Hixtra we have designed our equipment to be used with the largest variety possible including: 
Excavators 
Dumpers 
Forklifts 
Rollers 
 
The main consideration is always that there is enough weight acting on the test equipment underneath the plant to provide the loads and stresses you need. 

Excavator 

Heavy plant for high loads 

Dumper 

Lighter plant for smaller loads 

JCB 

Versatile and goes anywhere 

Roller 

Almost any plant will work! 

CBR Testing 

In general, if you are looking at measuring subgrade strength for road design or construction then CBR values would be the norm. 
 
The complicating factor here though is the material being tested. If there are particles in the subgrade that exceed 20mm then the traditional CBR test may not be valid and it would probably be best to go for an equivalent CBR test, which is the plate bearing test with an added calculation! 
 
If you are not sure what testing regime would suit you best, then at Hixtra we are just a phone call or email away to help.