Plate Bearing Tests
As part of our extensive suite of in-situ field tests, Southern Testing offer Plate Bearing tests.
Plate Bearing tests, as prescribed in the Eurocode and British Standards for site investigation, are conducted in near surface materials in order to establish the load bearing capacity of the ground. The test is crucial to the safe design of temporary working structures such as piling platforms / mats and when planning crane lifts as it is used to ensure that the ground can safely support the required loading.
The test is conducted by using a hydraulic ram to transfer a heavy reaction load onto a steel plate of known dimensions and recording the vertical displacement (settlement) over time for stepped load increments. The total load value divided by plate area gives the ultimate bearing capacity of the soil, expressed as a pressure. By modifying the test, this value can also be expressed as a CBR value, dependent on the designer’s preference.
Plate bearing tests are usually specified as part of compliance with industry guidance on temporary working platform design and the use of mobile cranes and are required before the lift or piling works can commence.
Lately, we have seen a significant increase in the number of Plate Bearing tests we have been asked to conduct. When planning a plate bearing test, there are a number of key factors, which it is helpful to bear in mind:
- Target Loading – The crane or piling rig operator should supply the loading characteristics of the machine in order to specify the test loads. Ideally these will state the bearing pressure or the mass and footprint of the plant.
- Suitable Safety Factor – When specifying the target load a plate bearing test, the designer should apply a suitable safety factor to the load provided by the plant operator.
- Heavy Plant Access and Availability – Because of the relatively high loads involved, a tracked excavator or other suitable plant is required for us to use as a reaction (kentledge) load. Typically this will be an 14 tonne machine. Where a large crane is required on site, it is possible that up to a 30 tonne excavator may be required. Obviously, site access needs to accommodate such a machine if one is not already present. It may also be necessary to consider whether a tracked 360º or wheeled “Rubber Duck” type excavator is the more suitable plant for the job.
If you require a crane or piling rig on your site, it’s highly likely you will need to conduct Plate Bearing Testing in advance of the planned work. For further information on testing arrangements, lead times or a quotation, contact our Field Operations Team