25 mm settlement see fig 1 k mpacm kgfcmcm where p

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Unformatted text preview: ; MPa/cm = & kgf/cm?/cm where P = load intensity 1.25 mm. corresponding to settlement Alternatively, the K-value may be defined ( 0.70 kgf/cma ) divided by the corresponding a standard 75 cm diameter steel bearing plate 0.07 MPa/cm 3 100 kgf, say ET= d Ii- = 0.70 -;T-kgf /cm*/cm where d = settlement 2.4 Stiffening for stiffening Plates - of plate of as a pressure of 0.07 MPa That is when settlement. is subjected to a load of 1 in cm. Nest of plates stacked on the bearing test plate it. I *Glossary of terms and symbols refating to soil engineering 4 (firsf w&ion ). 0 o-5 1;o l-5 SETTLEMENT FIG. 1 2-o 2.5 3.0 OF PLATE-mm RESULTOF PLATE BEARING TEST ON NATURALSUBGRADE 3. APPARATUS - ( see Fig. 2 ), 3.1 Bearing Plates - It is a circular mild steel plate of 75 cm diameter and 25 mm thickness. Smaller bearing plates of 45, 40 or 30 cm may also be used. 3.2 Loading Attachment - Loads are applied by means of a hydraulic jack or a screw jack working against a reaction frame through bearing plates. The loading attachment should have a capacity of at least 150 kN ( 15 000 kgf) equipped with ball and socket joint between the test load The device should have an arrangeand the jack to avoid eccentricity. ment for attaching to a truck, trailer, truss or any other equipment load reaction. 3.3 Jacks - Hydraulic or screw jack of 150 kN ( 15 OCOkgf ) capacity. 3.4 Proving Ring - One calibrated proving ring of capacity, 150 kN ( 15 000 kgf) with dial gauge to read to an accuracy of 0.002 mm. The proving ring should have an accuracy of one-half percent of the load measured. 5 6000kg min. 6000 kg min. PROVING RING BALL AN0 SOCKET STEEL JOIN1 CRIBDING DIAL max. ASTER THICK OF SAND PARIS cm 75cm NOTE - Support FIG. 2 for load reaction shall DIA DIA SUPPORT PLATE PLATE be 210 cm minimum from bearing plates. SCHEMATIC DIAGRAM OF PLATE BEARING TEST 3.5 Loading Reaction -- The reaction for jacking can be provided by a truck, trailer or anchor frame such that its reaction shall be at least 2.5 m away from the centre of the bearing plates. When the test is to bc conducted on granular subgrades, a reaction of at least 150 kN ( 15 000 kgf ) will be required. For cohesive soils a 50 kN ( 5 000 kgf) reaction may be sufficient. 3.6 Measuring Deformation --The vertical movement resulting from applied loads will be measured by at least three Gal gauges uniformly sp .tced 120” apart, preferably four uniformly placed at 90” apart, and placed at about 10 mm away from the rim of 75-cm plate. The gauges will be 6 1Sr 9214-1979 supported by an independent datum bar such that their positions are These supports should be at least unaffected by the loading operations. 2.4 m from the plates and the wheels. The settlement of the plate is taken as the average of the readings of the dial gauges used for the purpose. Gauges tifith an accuracy of 0.002 mm are desirable; however, gauges with an accuracy of 0.01 mm may be - sed if time-reading; are made. 3.7 Jack-Pads - Due to variation ia the depth of test points some distance pieces, for example, spacers, will be required between jack and proving ring. These can be solid cylindrical pieces of aluminium alloy or any other suitable material to withstand and help in transferring heavy loads on to the bearing plate. These spacers should be at least 15, ‘20 and 30 cm long. The exact requirement of these jack pads will vary from one test point to another according to depth of test point below ground surface. 3.8 Stiffening Plates -These : diameter and 25 mm thickness. are mild steel plates of 60, 45 and 30...
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This note was uploaded on 03/14/2014 for the course CE 684 taught by Professor Prof.deepankarchoudhury during the Spring '13 term at IIT Bombay.

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