Before conducting any construction, it is relevant to have plate bearing tests on the ground to be involved. The tests are necessary because they establish the vital bearing capacity of the soil on that land. The test requires specific hardware such as crane outriggers. The task is essential when building to determine the depths of foundation to create.
The plate bearing test process is conducted following the part 9: 1990 of the BS 1337 standard. The test requires some significant steps that involve various apparatus. The new testing method continues to grow day by day. The process includes load tests to the soil, coming up with settlements and determination of the bearing capacities.
The process requires the use of the following apparatus:
A hydraulic jack is used to spread on the heap and a platform to be used as a strong weight counterweight. A gauging instrument is required for the heaps created, a force to be accurately measured. Then you will need a 30cm radius bearing plate and reference beams. A plate has to be placed under the soil to operate. Packing and diversion version is done to the plates.
The hydraulic jack is the loading equipment in this process. Loads have to be placed on the usable plate and measured with a dial gauge that’s attached to the loading equipment’s output end. The bearing plates are steel made with a 75 cm diameter and thickness of not more than 3cm.
Settlement measurements are recorded as loading is done. The purpose of dial gauge comes in here, whereby they measure and give the settlement values. They have to be attached to the edge of the bearing plate from a well-supported datum frame.
The placement of the plate connected to the ground is done. It’s connected to the reaction load by a load cell. The plate bearing test location requires 75cm diameter sized plate with full placement on soil subgrade horizontally proceeding further with the process. Then the plate is subjected to a pressure of 0.07 kg/cm2, which is approximately a weight of 320kg on it.
The load is later released, and dial analysis settlement is recorded when the load removal happens. Loading for a settlement of 0.25mm follows. This amount is increased every minute while continuing to make records of dial reading of the settlement. The four recording has to be done. An average has to be calculated to come up with the approximate on the plate that offers consistency with the load applied.
The procedure involves an increase of pressure with the same rate of 0.25 mm with records keeping continuation until it reaches the value of more than or equal to 1.75 mm. The results are likely to remain the same if tests are continued further. After final testing is conducted, discharging of the loads in water pump has to be done to allow plates to improve. The remainder settlement can be recorded.
After recording and checking the outcomes, a graph plotting has to be done to represent the loads used against the settlement values recorded. Where two straight lines meet represents the point of failure. The ultimate load will be where corresponding settlement equals the one-fifth of plate width. To find the point needed, check where the curve breaks the load matching.
The figure obtained can be used as the bearing capacity figure that’s the best soil bearing capacity for the intended foundation required to be built at that location. It's recommendable to use soil at different conditions such as wet and dry to come up with more better conclusions.
The ultimate bearing is merely the soil’s safe bearing. The plate bearing test is a vital step in obtaining the knowledge of the specific ground, which enables easy determination of the kind of foundation to be laid for a construction.