PILE LOAD TESTPILE LOAD TEST

Pile Pile A deep foundation to transmit

structural loads through weaker zones to soil of desired capacity.

Basically two types ; i)End Bearing ii)Friction

Load carrying Capacity of Load carrying Capacity of Piles by-Piles by-Static AnalysisDynamic AnalysisLoad Test on PilePenetration Tests

Load Test on Pile:Load Test on Pile:

Load through hydraulic jack resting on reaction girder.

Test after 3days in sandy soils and after 1month in silts and soft clays, to allow restoration of original properties of soil.

Load applied in equal increments of abt 20% of allowable load, corresponding settlements recorded in dial gauges.

Each loading maintained till rate of movement of pile top is - ≤0.1mm/hr in Sandy Soils

≤0.02mm/hr in Clayey ormax of 2hrs

For each load increment, settlements are observed at 0.5,1,2,4,8,16,20 and 60min

Loading continued upto twice the allowable load or upto the load where total settlement reaches a specified value.

Allowable Load as per IS:2911-Allowable Load as per IS:2911-Part 4-1974:Part 4-1974:Lesser of following;50% of load at which total settlement is

equal to one-tenth of diameter of pileTwo-thirds of load which causes a total

settlement of 12mmTwo-thirds of load which causes a net

settlement of 6mmLimiting settlement criteria : Under load twice the

allowable load,net settlement shouldn’t be more than 20mm or gross settlement should not be more than 25mm

From graph;From graph;

Lab ;Large steel tankSand is compacted upto 45cm

depthSet up is fixed-test

pile(H=30cm,D=50mm),proving ring(L.C-4.6kg/div),dial guages(L.C-0.01mm)

Settlement corresponding to each 5divisions is noted

PLATE LOAD PLATE LOAD TESTTEST

Measure deformation and strength of soil

Used for determine bearing capacity of soil and its settlement especially for shallow foundation

Bearing Plate :Steel plate(Bp )of min size of 300mm and

max of 750mm with min thickness of 25mm.

Larger plates for cohesive soils.Pit Size :B = 5xBP , Depth of pit = Depth of

foundation Df

Depth where plate is to be placed from,

(Dp/BP ) = (Df/Bf )

Loading on Hydraulic Loading on Hydraulic jack :jack :Gravity Loading and Reaction

Truss method Method

Procedure: (Procedure: (IS:1888-1971IS:1888-1971))Base of pit is levelled,small hole is

dug and plate is inserted on little sand spreaded.

Seating load of 7kN/m2 applied and released.

First increment abt 10% of anticipated Ulti B.C ,settklements recorded for 1,4,10,20,40 and60min and later at hourly interval until rate of settlment is less than 0.02mm/hr or atleast for 24hours

Procedure :Procedure :Test is repeated by applying load

increments ,continued till a load of about 1.5 times anticipated Ulti Load is applied or a settlement at which failure occurs or atleast 25mm should be reached.

Plot is made b/w Load internsity and settlement.B.C determined from the plot

Uses :Uses :

1.Ultimate B.C : Clayey- qu (f) = qu (p)

Sandy – qu (f) = qu (p) x (Bf /BP )2.Settlement of Foundation :

Clayey – Sf = Sp x (Bf /BP )Sandy - Sf = Sp x (Bf (BP+0.3 ) /BP

(Bf+0.3 ))2

Uses :Uses :

3.Designing Shallow foundation by trial and error procedure by using

qo = Q/Af

4.Detremination of influence factor I from

Si = qB((1-µ2)/E))I

plot b/w Si and qB is made which is a st.line,slope is found out i.e (1-µ2)/E)I

knowing µ and E ,I is found out

Lab :Lab :Size of plate = 10cm x 10cmSize of Tank 49cm x

49cm,Height=60cmSand filled upto 30cm i.e 3times

size of plate and compactedSand is filled above bearing plate

for 10cmLoad v/s settlement curve is

plotted