Plate loading tests

The plate load test is well known and, like the standard penetration test, has been in use for a long time period, but neither of these two tests is used very often when the water depth is greater than about 30 m. A limited niunber of plate bearing tests (plate loading test [PLT]) have been carried out at three locations in the North Sea typically, a seabed jacking system has been used to load the plates. The main limitation of the PLT is that it only tests the upper 0.5-1.0 m, luiless it is of the screw-plate type (Kummeneje, 1955 Schmertmann, 1970). 

Results of two plate load tests in a dense North Sea sand. (After Andresen, A. et al., Marine Geotech., 3,201-266, 1979. Reprinted with permission of Taylor Francis Group.)... 

The use of this equation is not recommended unless the ( foundationV piate is not much less than about 3. When the ratio is about 6 to 15 or more, the extrapolation from a plate load test is little more than a guess that could be obtained at least as reliably as using an SPT or CPT correlation. 

Limited plate load tests have been carried out within the base of an excavated caisson (Amp 1996 to 2001). The end bearing mobilized was relatively high (fi = 501V). The modulus E was found to be 70,000 kPa. 

Review in situ test results e.g. by carrying out rock drilling tests (check rate of penetration) or localized plate load tests. 

ASTM D 1195/D 1195M. 2009. Standard test method for repetitive static plate load tests for soils and flexible pavement components for use in evaluation and design of airport and highway pavements. West Conshohocken, PA ASTM International. 

The screw plate is a variant of the plate load test in which a helical screw is rotated into the ground to the depths at which the test is to be conducted. The test has the advantage that no excavation or drilling are needed, and it can be performed beneath the water table. Unfortunately, however, screwing the plate Into the soil may cause disturbance around the plate. 

Variations of the plate-load test include the freyssinet jack test. This is placed in a narrow slit in a rock mass and then grouted into position so that each face is in uniform contact with the rock. Pressure then is applied to the jack. Unless careful excavation, particularly if blasting, takes place in... 

Plate 15. Standard plate load testing apparatus for determination of insitu modulus of deformation. 

A direct method to verify the bearing capacity in the field is the execution of a Zone Load Test (ZLT) (ICE, 1987) which, in fact, is a large Plate Load Test (PLT). 

Stiffness is normally not a parameter that is defined as a project requirement. Only for specific tests a stiffness requirement can be defined, such as for the Plate Load Test. 

However, specifying a stiffness without referring to a detailed description of the test method, can lead to a misunderstanding of the project specifications. Reference is for instance made to the stiffness used in the field of road construction which is often empirically derived from a CBR value and relates to a dynamic stiffness which is much higher than the stiffness under static loading conditions (e.g. the Plate Load Test see section 11.3.3.1). 

After a preloading period of 3 to 5 months, the fill mass was finally consolidated from a soft (fluid) mud to a clayey soil capable to withstand a pressure of 50 kPa during an in-situ Plate Load Test. Based on the tests results the required specification for acceptance was realized. The results of the field tests are listed in Table 9.5. For comparison, the initial status of the mud just after filling is listed as well. 

Occasionally it may be preferable to directly measure the required fill mass properties. Zone Load Tests and, to a lesser extent, Plate Loading Tests give reliable information about the stiffness and the strength of the fill mass. 

It is not realistic to specify a standard format for a Quality Control Program prescribing a fixed number of monitoring devices such as Settlement Markers, Cone Penetration Tests, Plate Load Tests, Zone Load Tests, etc. for land reclamation projects. Lor the definition of such a program it should be realised what has to be monitored and, in particular, why it is to be monitored. The main goal of quality control is to verify whether the specified dimensions of the reclamation and the quality as well as the performance requirements of the fill mass are satisfied. Examples of aspects that need monitoring in land reclamation projects using hydraulic fill material are presented below ... 

The Plate Loading Test is a more appropriate test method for determining the bearing capacity and load-deflection relationship of the materials used for roads, airport runways, pavements, etc. 

For testing the actual behaviour of future foundations. Zone Load Tests are more meaningful than Plate Loading Tests. They are, however, more time consuming and more expensive than Plate Loading Tests. 

Plate loading test, CBR test All soils Stiffness Carried out a the surface of a reclamation area... 

Figure B.42 Influence depth of Plate Loading Test (PBT) and Zone Load Test (ZLT).

ASTM D1196-93 Standard Test Method for Nonrepetitive Static Plate Load Tests of Soils and Flexible Pavement Components, for Use in Evaluation and Design of Airport and Highway Pavements, 2004... 

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