 In last class, I have discussed about how to calculate the pile load capacity by using pile load test. So, now in that class, I have discussed about the total load carrying capacity of the pile. How will calculate the total allowable load carrying capacity of the pile by using pile load test. Now, if we want to know the contribution from the tip resistance and the friction part separately, then you have to go for the cyclic pile load test. Now, in this section, I will discuss about the cyclic pile load test and how to determine the frictional resistance of the pile and the tip resistance of the pile based on this cyclic pile load test. Now, this section will give the vertical cyclic pile load test. Now, here this is carried out to separate the pile load into the skin friction and point bearing on single pile of uniform diameter. Now, suppose if we do the load test, this if I draw the graph. So, for the static load, we will get say these are the different load q 1, this is q 2 and say this is q 3. So, these are the increment different increment q 1, q 2, q 3 and there because we are applying the load in 20 percent of increment. So, here it is the load corresponding settlement that we will measure. Similarly, this is the load and corresponding settlement that we will measure. So, this is the value and this is the load and corresponding settlement this will measure. So, this is our if I join this point. So, this will give us the static pile load test and there. So, this will give of the this is the load and this is the settlement. So, this settlement this will give us the static load pile load test curve. Now, similarly here once we get this type of graph. So, and then the others q 4 and q 3 or q 5, then we will get complete the graph and then if we want to determine the allowable load carrying capacity of the pile, then apply those conditions. Suppose, one is a two-third of the load by which the settlement attains a value of 12 millimeter. Suppose, this is 12 millimeter, then we will calculate suppose this is the load 12 millimeter, then we will calculate the q value corresponding 12 millimeter and then we will take the two-third of that load. Similarly, we go for the second condition, then we will go for 50 percent of pile diameter, then we will get one settlement corresponding load 10 percent of the pile diameter for the uniform loaded pile and then we will go for the that q and take the 50 percent of that. Similarly, you have to consider the all the condition and the minimum of that q will consider that is the allowable load carrying capacity of the pile. But, there we cannot know what is the contribution from the skin friction and what is the contribution from the tip resistance. We are here we are getting on the total load carrying capacity or allowable load carrying capacity of the pile. Now, here by the cyclic test we will calculate, we will know what would be the contribution from the friction resistance and what is the contribution from the tip resistance. Now, in the case of cyclic load what I will do? So, this is the previous graph for the static pile load test and this is for the vertical cyclic pile load test. Now, this test is limited only to the initial test not in the routine test. Now, here the graph that we will get suppose this is the q or the load on pile, pile top that is in ton and this is the settlement in millimetre. So, this is the first increment say q. So, we will apply the loading up to q then we apply the unloading. So, this is the q and here we will get two settlement. The next one we will start the q 2 and here we apply the loading curve and then this is the unloading part. This is corresponding to q 2. Similarly, for the q 3 we will go for the q 3 and then we apply the loading and the unloading and then we will go on for the q 4 and so on. So, now here if I go for the every step here we will get the this is our total settlement or S t 1. This is the total settlement for the first loading increment. So, there is a two parts one part is you can see. So, this portion is the permanent settlement and this is the recovery part. So, that means this portion is the elastic settlement and this portion is the plastic settlement. So, there is a permanent set of the curve then it is when you unload the this portion this in the last point is not the first point or the starting point. There is a permanent set. So, that set is the plastic settlement S p 1 and the recovery portion is elastic settlement S e 1. Similarly, for the second set also this there is a two part one is the total. So, from this is the total and then this is the plastic settlement and this is the elastic settlement. So, now every increment of loading will get one plastic settlement one elastic settlement that is for every increment. Now, if I write that settlement or the total settlement if S is the total settlement. So, that S total settlement is the summation of elastic settlement plus summation of plastic settlement. So, S e is the elastic settlement where S e is the elastic settlement and S p is the plastic settlement. Similarly, the total q that we are getting that is the combination of friction resistance and the tip resistance and we can write. So, that elastic settlement and the combination of the summation of elastic settlement and plastic settlement is the total settlement. Total load is the summation of friction resistance plus the tip resistance. In other hand we can write the total settlement is the summation of del l plus S b. So, now where del l is the total settlement equal to compression of pile material pile or pile material and S b is compression of soil at the base. So, that this is also S b of two component elastic part and plastic part. So, this is the elastic part and the plastic part. So, we can say this is the S is the total settlement that is the elastic settlement total elastic settlement and total plastic settlement and here S that will get the compression of the pile material because that plus the compression of the soil at the base. So, at the base soil also so that means the total settlement it is due to the summation of the soil settlement at the base. So, base soil that will settle because of that we will get the settlement of the pile and the pile material that may also compress. So, that is the summation of the compression of the pile material and the compression of the base soil. Similarly, the base soil also there is two types of settlement one is elastic settlement another is the plastic settlement. So, and in the pile material also we can consider two types of settlement one is the plastic settlement and the elastic settlement. So, the total elastic settlement is the summation of elastic settlement of the pile material and the elastic settlement of the base soil and total plastic settlement is the plastic settlement of the pile material and plus the plastic settlement of the base soil. Now, here if I further write this expression in different form, then you will get that again we can write this S P dash is the plastic compression of the soil at the base, elastic compression of the soil at base and S P dash is the elastic compression of the soil this is the plastic compression of the soil at the base. So, finally, we can write the total settlement is del L plus S E dash plus S P dash and again we have written that S is total elastic settlement plus total plastic settlement. So, if I compare these two expressions, so S E plus S P that will be del L plus S E dash plus S P dash. So, we can write that S E dash elastic settlement of the base is S P minus S P dash plus S E minus del L. Now, this S P and S E that we can determine from the figure or the pile load test that load versus settlement figure and this if I this del L we can calculate by this expression that q minus q f by 2 minus into L divided by A E, where q is equal to total load on the pile q f the frictional resistance frictional load or resistance is the length of the pile A is the average cross section area of the pile E is the modulus of elasticity of the pile material of the pile material. So, this is the E is the modulus of elasticity of the pile material. Now, if we consider that the plastic settlement of the pile material is negligible, because the plastic settlement total plastic settlement we are taking the summation of plastic settlement of the pile material and plastic settlement of the base soil. So, here we assume the plastic settlement of the pile material is negligible. So, we are taking all the settlement of the pile material is elastic, because the pile material is very steep compared to the soil. So, the plastic settlement is plastic settlement of the pile material is negligible. So, So, total settlement will be, total plastic settlement will be plastic settlement of the base soil, because plastic settlement of pile material is neglected, as is neglected, in that case sp will be sp dash. So, from this expression, so if I write this is expression 1, so from equation 1 we can write or equation this is 1, we can write that s e bar is s e minus del l. So, this is the expression or the final expression. So, here del l will calculate by this expression and s e have to determine from the pile load load versus settlement graph and then we will calculate the s e bar. Now, the next step how to determine the q f and q p, the next step determination of q f and q p, q f is the frictional resistance and q p is the base resistance. So, here first what we will do, we will draw a graph, so this is load on pile top and this side this is the elastic compression of soil or sub grade, so this is the elastic base soil. So, you can write this is s e bar, so this side is s e bar and this side is load on the pile. So, first step we assume that del l is 0. So, what we will get from this load versus settlement curve or the first curve, so that I have drawn this for the pile. So, from this first curve we will get what is the s e for a particular load intensity. So, for a particular load intensity what is s e. Now, if we consider that because our expression is s e bar equal to s e minus del l, so that is the expression and for the first step for step 1 assume del l is equal to 0. So, this s e for any load increment we will get from the previous curve or load versus settlement curve and then we will get the s e. So, in that case s e that is s e bar is equal to s e for the first step, this is for the first step only. So, what we will do now we will draw this graph corresponding to different loading points. So, we will draw, so this is say curve 1, this is for the first step where we assume that del l is equal to 0. Now, the next step that what we will do that we will draw one line which is parallel to the straight portion. Now, this is the straight portion of the graph. So, here we will get one non-linear portion then is a straight portion of the graph and we draw one parallel line which is passing through this origin and parallel to the straight portion of this curve 1. So, which is passing through the origin and this is this graph is parallel to the straight line portion of curve 1. So, this is parallel to straight part of curve 1. Now, from this graph we will determine what would be the value of here for the first step from this graph. So, this part will give you the point resistance of any loading increment for this loading increment say. So, this will give you the point resistance and this part will give the frictional resistance. This is the skin friction or q f and this is the q b part q b or p part. So, or any loading position say from this portion here this portion is q p and for this is the friction resistance part. So, here that will determine. So, once we get this any loading condition we will get the q p and q f. In the second step once we get we know the q f value because that expression of del l del l we are giving that is the q minus q f divided by 2 into l divided by a e. So, a is the material property l is the length of the pile and q and q is the total load at load or the load increment at any point and once we get the q f from this part because this state portion this state portion left hand side will give you the q p and this right hand side will give us the q f. So, once we get the q f at any loading increment from this graph we will get the del l. So, for the any loading increment we will calculate the del l and that del l will put here and a c is previously we can calculate from the load that is the displacement curve and that is the same as the step one. So, now we will get a new a c bar. So, once we get a new a c bar then we will draw another curve by using the new a c bar. Suppose that is this curve is the new a c bar or the step two. So, this is our step two where we calculate new a c with new a c bar. So, this is say curve two. Similarly, this curve also we will get one state portion we extend this state portion of the curve and again we will draw the parallel line of this state portion. So, this is the parallel line for curve two and similarly we will repeat the same thing here also we will get the q p and q f separately from the left hand side of this part. So, this portion is basically this portion is q p and this portion is q f. So, this here also this is q p the q f the q p and q f for the first part and this is this portion is q f and this portion that means the right hand side of this straight line which is passing through the origin state parallel to the state portion of the curve right hand side of this curve is q f and left hand side of this curve is q p. So, once we get this value then we will calculate the new del l and then we will get the new again in the step three we will get another a c bar or the new a c bar. Then we will get another we will calculate another curve. So, this is our curve three and again we will extend this the state portion and they will again draw this parallel line for the state portion of this third curve and again we calculate the q p and q f and again we repeat the same you calculate new del l we will calculate the new a c bar and you repeat the thing unless the two curves are maintaining this curve are matching each other and generally it is observed that after the three trials these curves are matching each other. So, this so when these curves are matching say suppose curve three and curve four are matching each other then we will stop there and then from that curve itself similarly from this state portion right left hand side will give us the contribution from the q p that means this left hand side and the right hand side of this state portion which is passing of the of the line which is passing from this origin right portion right hand side of this curve up to the original curve that will give us the friction resistance. So, one so for this method we can determine what is the contribution from the tip resistance and friction resistance separately. Now this will give us the ultimate load carrying capacity of the friction or contribution from the friction and the tip separately. Now if we want to find the shape pile capacity then you have to divide these things by factor of safety. Now for the skin friction resistance so that if we divide this part by factor of safety we will get the shape friction resistance and shape bearing resistance that we are getting from this pile that we can determine from the pile load test. So, by this method a cyclic pile load test we can separately determine the contribution from the friction part or friction resistance and from the tip resistance of the pile by this pile load test. Now the next section that on the next section we will discuss about the pile load test for the different dynamic pile formula because this is the third method because the first method was static expression. Now this second one that I have discussed from the pile load test. Now next one that we will discuss that I will discuss that is dynamic pile formula. So, this is the formula that will give you so first one will giving the record or E N R formula. So these are the based on the pile driven energy or the weight that we are using based on that we are calculating this allowable load carrying capacity of the pile. So q allowable or the allowable pile load that we can calculate by w into h into sigma h into s plus c where w is weight of the hammer and h is the height of falling, s is the real set per blow, c is the empirical factor, f is factor of safety usually taken as c is the weight of the pile and this is the efficiency. Now for the draw hammer this value is 0.7 to 0.9 for steam hammer this value is 0.75 to 0.85. So now this equation or this expression is based on the energy that we are applying to or to drive a pile into the soil. So this is the weight of the hammer is the free fall height is efficiency and this factor of safety which is generally taken as 6 s is the set real set per blow. If we apply the load how much is the amount of the real set per blow that is s and c is the empirical factor. Now this expression is based on the energy that we are applying to or to drive a pile now this expression we can use for different hammer. So now for the draw hammer this q a is w into h and this is the efficiency into 6 factor of safety and s plus 2.5. This is for the draw hammer where q a and w this is in kg and this is the weight of the pile load that is h in centimeter s is equal to centimeter per blow that is the final set or the real set or the final set. So this final set s we can take that is value that the average penetration for the last 5 blows of a draw hammer or 20 blows of the last 5 blows of a steam hammer. So that means this s centimeter per blow here the final set last 5 blows average that we will consider as the s in case of draw hammer and for last 20 blows of in case of steam hammer the average of last 20 blows penetration that we will consider as the s value in case of steam hammer. So similarly for the steam hammer or single acting steam hammer this q a is equal to w into h into efficiency plus 6 plus s into 0.25. So here for the draw hammer c value is 2.5 for the steam hammer this is 0.25. So this again this w and q a is in kg h is in centimeter s in centimeter per blow and this is 0.25. So by using this expression also we can determine the pilot carrying capacity of the pile. So now there are other this type of expression are also available but here I am just giving one expression which is very popular that is a E N R formula and by which we can also determine the pilot carrying capacity. The next one the fourth method that we can determine the pilot test by using the correlation with the penetration test data by using with penetration test value. That means by SPT or CPT value we can determine the pilot carrying capacity of the pile. Now first we will give in the for the driven pile in sand. So driven pile in sand. So here q P u that means the this is the T resistance ultimate T resistance that is 4 T N into L by D which is in kilo Newton per meter square. But that should be less than equal to 400 N kilo Newton per meter square. That means this if we use this expression now that q u P cannot be greater than 400 N kilo Newton per meter square. So that means if it is coming more than 400 kilo Newton per meter square N kilo Newton per meter square then you have to consider the 400 N kilo Newton per meter square. So that means so this will limited to this value that means this is the ultimate T resistance. Similarly for the driven pile we can find the q P u that is q c. This is based on the SPT value. This is the SPT value. So this is SPT value is observed value without any correction. So this N is observed value without any over burden correction. Now again by the q c that means the cone resistance. This is the cone resistance of you can determine the ultimate T resistance of the pile. Now q c is taken as the average value of q c over a distance 3 D above and 1 D below the level of the pile T. That means this q c value suppose this is the pile T portion and this diameter is say D. So that we can take the average value of this is 3 D and 1 D. Then this is the tip. So the average value of this 4 D portion the 3 D above the tip and 1 D below the tip that average value of q c that we have to consider as this q c. So that means for the pile to attain its full bearing resistance it should be driven at least 5 D inside the bearing stator. For the pile attain its full bearing resistance that means for the pile attain the full bearing resistance it should be driven at least 5 D inside the bearing stator. Suppose if there is a bearing stator is there. So this is suppose the bearing stator inside this this one is the bearing strata, bearing layer, then the pile is has to be penetrated inside this strata at least for the 5D part, then you will get the full resistance, this is the at least. See if one pile is penetrated that this bearing layer or the bearing strata at least for the 5D length, then you will get the full resistance from this strata. Now that means here the this QC value will take the average of this 3D above the tip and 1D below the tip, this average of this 4D zone will get the QC, average QC will give the QC and if we get the full resistance of this any bearing strata then this bearing strata this pile has to be penetrated at least 5D below this within this bearing strata. Now the friction resistance this is the we are talking about the ultimate tip resistance then how to get the friction resistance, the friction resistance of the pile. So for the driven pile here the same thing for the driven pile in sand. So we are talking about this pile in sand the friction resistance F s we can take the QC average by 2 that is in kilo Newton per meter square and this is for the displacement pile or this is for the displacement pile and F s is equal to QC average by 4 this is kilo Newton per meter square this is for the H pile. These expressions are given by the both the expressions given by the mayor of in 1956. Now QC average is the average cone resistance along the length of the pile, this is the average cone resistance along the length of the similar this is in terms of cone resistance similarly for the in terms of n value this Q s is equal to n average this is also kilo Newton in meter square this is for the displacement pile or Q s is equal to n average that is in kilo Newton per meter square this is for the H pile where n average this is the SPT value this is the average field value of n this is the SPT along the length of the pile. Now another condition that here for the Q p m that means the tip resistance also that that cannot be greater than 400 n value similarly the for the displacement Q F s that is less than equal to 100 kilo Newton per meter square this is for the displacement pile and that is less than equal to 50 kilo Newton per meter square that is for the H pile. So, this is the one of the two condition. So, these are the expression for the driven pile in the sand next one will give the expression for the board and cast in C 2 pile in the sand this is the board. Now again we will get the Q p u that is equal to one third of Q p u that we will get of driven pile and F s that is equal to half of the F s of driven pile. So, first we will calculate the Q p u and F s for the driven pile and then we take the one third for the board and cast in C 2 pile in sand and F s is half of the F s of the driven pile. Next one is the driven and cast in C 2 pile. Here for the cast pile it is same as driven pile and for the uncased pile the F s as driven pile the F s same as driven pile. Now if proper compaction is done or either we can take F s as board cast in C 2 pile if proper compaction is not done. So, these are the condition or these are the condition by which you can determine the pile load carrying capacity of the pile or the trip resistance of the pile or the friction resistance of the pile based on the penetration test data that means the cone resistance or the n value or the spt n value. We can determine this for the driven pile we can determine board cast in C 2 pile we can determine this for the driven cast in C 2 piles also and then in the different pile condition in the cased pile uncased pile on all these cases we can determine the pile load capacity of the pile by using this penetration value. So, there is four different methods by which we can determine the ultimate load carrying capacity of the pile or allow by load carrying capacity of the pile. One first one is the static method or static equation or the formulae. Next one second one is the by the pile load test. So, for the static or the cyclic if I go for the cyclic pile load test then we can determine separately the friction resistance and the trip resistance and third one by using the dynamic equations or the formulas and formulae and the next one in the third expression is by using by using the penetration test data. So, these are the all different methods by which we can determine the pile load ultimately pile load capacity of the pile different piles and then in the in this section I have also discussed that when you go for the group analysis or group calculation then how we will calculate this group efficiency of the pile and group ultimate load carrying capacity of the pile. Now this in the next section I will discuss about the settlement of the pile then the how to calculate the load bearing capacity of the under rim pile then those things I will discuss in the next section. Thank you.