Plate bearing test procedure

Plate Bearing

What is plate bearing?

Plate bearing tests are done to locate the most astounding bearing limit of the ground, and it is normally taken out at the establishment level. The tests require an abnormal state and a high cost of hardware, for example, working stages, crane outriggers and pilling rigs. Certain wellbeing measures must be set up, obviously, to guard the labourers against wounds.

 

The Procedure

The procedure for plate bearing tests have to be according to BS 1337 Part 9: 1990 Standard, this is an advanced procedure which gives the plate bearing of the soil. The test is a long process, and it comes with a large amount of apparatus.

 

Apparatus

  • Hydraulic jack for applying the heap
  • Platform as a counter weight made out of a strong material. This should be over 10% more than the predicted test load
  • Measuring instrument – proving ring for measuring the force created by the load
  • Bearing plate of a small size up to 600mm diameter
  • Reference beams, called dial gauges

The procedure starts firstly, by placing the bearing plate on a thin layer of dry and clean sand, which is on a level surface.

Then, set up the stacking and diversion, measuring frameworks so the heap is connected to the plate without flightiness and the avoidance framework is outside the zone of the impact of the attachments.ziplate. Amid these operations, a little warming burden might be connected to the plate to empower changes in accordance with being influenced: this seating to stack should be under 5kN/m2.

After that, the heap should be connected in five additions. Settlement perusing will be taken at half-minute interims for the initial 2 minutes, and 1 minutes interims from that point, until the point when the discernible development of the plate has ceased, i.e. until the point that the normal settlement rate is less than0.02mm per 5-minute interval.At every augmentation, the weight should be kept up as close as conceivable consistent.

Finally, after the last test increase has been finished, the weight in the water powered pump should then be discharged and the settlement of the plate permitted to recover.When the recuperation is basically entire, the remaining settlement esteem might be recorded.

 

Calculations/Graphs

There are four main calculations and graphs needed to be done inside of the test. The first of these is a line graph showing four curved lines for different types of soil. The line showing ultimate bearing capacity is too much in that type of soil to be used. Line A would be a line representing loose cohesion soil, this will show no point of failure. Line B is drawn when the soil is cohesive. Line C is partially cohesive soil and line D is dense cohesionless soil.

The second calculation is ultimate bearing capacity, which has two different straight lines and where they meet is called the point of failure. For example, if curve A and D were very curvy, you could make a line showing the tangent parts and the failure point.

Thirdly, with a specific end goal to ascertain the protected bearing limit of the dirt, separate a definitive bearing limit of soil by an appropriate factor of wellbeing. Safe bearing limit of soil = Ultimate bearing limit/Factor of wellbeing The estimations of a factor of well-being typically utilized are 2, 2.5 or 3 relying on the site condition and significance of the structure.

Lastly, the step which requires calculating settlement of proposed footing. These are four things you need to know before I carry on:

Sp = Settlement of plate (mm)

Sf = Settlement of footing (mm)

Bp = Width or dia of plate (m)

B = Width of footing (m)

This is the calculation, discovered by Terzaghi and Peck, that needs to be used to calculate the proposed footing, Sf = Sp {[B*(Bp+0.3)] / [Bp*(B+0.3)]}2.

 

Video on Plate load testing Calculations

Advantages

One advantage is that you will get a greater knowledge of the behaviour of the ground/foundation, which will help trigger an evaluation.

Another advantage is that it is a quick process, and is easy to perform after the equipment is set up.

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