So, last class I have discussed about the

tension pile and the pile subjected to lateral loads now, when the structure which heavily

loaded then we have to go for another type of de-foundation that is called foundation.

So, that is useful for heavily loaded structural line bridge foundation where we generally

use this well foundation. So, today’s class I will discuss about various components of

well foundation and then how to determine the depth of well foundation. So, now, first

what are the different types of well foundation? As I mentioned that this is used for, for

heavily loaded structures so and then what are the different types of well foundation?

So, depending upon that construction methodology they are the different types of type of well

foundation. So, first will go so, for that is well foundation. The first types of well; now, first type that

is called open caisson or open well. Now, in this type that this is existing mid-level

below in a river now here is shown is the water level. So, this is water level this

is the existing these of the water body or the river. And then open well the top and

bottom is open during construction so that means here opal open well is allowed

to sink into the water this is another. And then this portion is filled with concrete so that shown it is the open type of well

that here top. And bottom portion is open during construction that mean during construction

this top portion this is the top and this is the bottom portion. So, these two portion

open during construction. And then this can be circular type and this can be rectangular

type also and the possess of sinking is continue till reach the required depths. So, that means

these possess when it is sink, sink into the water.

So, it is continue till the required depth is reach now once the required depth is reached

then the bottom portion is sealed with concrete. So, this one required depth is reached is

bottom portion is sealed with concrete. And then the shipped this is over the portion

in a sapped which are filled with sand now once that means during the construction this

top portion. And the bottom portion are open once the it is reach at the ground surface

or the required depth. The bottom portion is sealed with concrete and the shaft is filled

with sand. Now, advantage of these type of open well, well that the, it can become stuck

trade of up to inhale depth the, of the up to the required depth and with a credibly

low-cost condition. So and the limitation or disadvantage of this

open well is the, if the bolded deposit is there. If the, this ground surface or this

bottom of the water body is there well bolded deposit represent. Then it is maybe difficult

to in possess or progress the construction of this type of well. And then very slow at

may this if deposit this is very slow construction and a concrete sealed is done under the water.

So, that means one it is reached in the bottom then the concrete sealing is done under the

water which is not very effective. And that is the advantage and the disadvantage of this

open well or open caisson. So, next type of the well is that is called box well of floating

caisson. So, this is second type of well foundation

so here again if this is water surface and this is the well

and this is the ground of the water body;

this is top bottom. So, in case of first case with the top and bottom both are remain open

during the construction, but in this type of well top is open but the bottom is close

during construction. So, this is the closed bottom and this is the open top so that means

this type of well the top open at top and closed at bottom. So, this is cast in land

so that means before this is this is as it is closed. So, during the first case the bottom

was sealed after it is reached up to the desired depth. So, that means the casting was done

under the water which was non so effective for the first case top well. But in case of

bottom box well floating caisson the construction cost is done in the land because as this is

the sealed or the bottom is closed condition. And can be used when land is not very, that

means this can be used when the load is not very heavy. And we are in strata is up to

a shallow depth that means a up to shallow depth. This can be done and the advantage

of this type of well is that that foundation when has to be prepared before and so that

advantage this advantage then this is the construction is done in the land. So, it is

effective and the disadvantage is the before the it is placed into the ground. The land

has to be prepared so and the bearing capacity of the base has to be properly calculated

so that otherwise it, it is be difficult to construct this type of well into the soil.

So, that means when we calculate the this prepare the and then the calculate the bearing

capacity all this case factor. Then the, this covering on the foundation action has to be

a a incorporated during the calculation. So, next type of well that is first one is

the open caisson then the box well and the second one is the pneumatic well. So, this

pneumatic well is another type of well foundation so, that is in this is water surface and this

is ground surface. So, this is constructed in an dry condition so in this well the, this is and excavation is done under the dry condition.

The when once the tip required depth is achieve the working chamber is filled with the concrete

and the advantage of this type of well that the better control during the sinking. And

the suspension can be done the bottom of the chamber can be sealed effectively with concrete

under dry condition. So, that means is here the first case the concrete bottom of the

concrete was sealed under the below the water so which is not so effective. But here the

concrete heating is done the bottom of the concrete it is sealed under the dry condition

which is so effective. And the disadvantage is the, the cost of this type of well is very

high. And the limit of the depth of the penetration below the well is around the 30 to 35 meter.

So, that means if we compare the 3 type of well that the first one is a top well where

the concrete is done below the water the width condition which is not so effective. And the

second one is concrete is done costing is done in land, but the second one which is

applicable if the bearing strata is, are the shallow depth. And during so and the bearing

capacity calculation has to be properly done. And the third one is it is also done up to

the required depth, but the advantage is that the concreting is done under dry condition

which is very effective and the disadvantage. And all the advantages explain for the different

types of this well in the first case a cost is not high, but concrete is being done in

well width condition in the last case it is so high cost is high. So, these are the limitation

and the advantages of different types of well and depending upon the cost of the project

and the type of the land or the, the base condition. And we have to use the different

types of well foundation now next part is that the components of the well foundation.

So, what are the different types of components of the well foundation? So, first for the different types of component

has to be if we draw. The first this is the pile or that above that pile will we have

to place this in order that is the, that is placed above of bearing. So, this one is the

girder this one is the bearing. So, first this is bridge girder then this is bearing

then which is placed in a pier this is top portion then this is pier. Then this various

components of this well that will start then this is our different components. And this

is what we called in first meant of the pier this portion is it is a concrete in this shown

is the bottom plug. So, when this is the top plug where again the concrete in is done sealed

with top plug in this is the bottom plug

and here this is sand fielding. Now, these are the various components of the

pier. So, these are this is the well so, this is pier then this one is called as the top

plug

then this one is bottom plug. Then this is cutting edge and this is sand fielding then this one is

well cap

then this is the body of the well main body of the well that will well staining. Now,

these are the various components of the well and now the pier which was the section of

the same well. Then we can draw like this these are the horizontal; this is vertical

reinforcement; this is horizontal reinforcement so these are the various components. So, now

the purpose of this various type of components so in this top filling the, this provides

context between the well cap and the sand filling. And this helps to transfer the load

which is coming from this structure to the sand filling. So, from here pier caps it will

transfer the load from pile to the sand filling that is the purpose of these top plug.

Now, the well cap which is made up R R C slab so that is a cast with the staining. And the

well staining that is the main body of this well and the bottom plug after the well is

sync up to the desired level. Then in the, this is plugged with concrete and this concrete

is done for this different types of well it is done in different condition. Now, this

is the cutting edge the purpose of this cutting edge is so cuts the soil during the sinking

now and this the various components of this well and the purpose of this components are

expects. Now, secondly that during the construction of the excavation of the hole the, a dredge

hole is formed. Now, the definition of this dredge hole is that is that this is the hole

form during the excavation of the soil and which is filled with sand later on.

So, that means during the excavation this hole is form and this hole is called the dredge

hole which is filled sand later on. So, that means this is the definition of this one is

the hole which is form

due to the excavation of soil during the construction. So, later on it is filled with sand so these

are the various components. So, this is the section and these are the horizontal reinforcement

and this is the vertical reinforcement which is shown here. So, next part is that, what

are the various type of shape of the well? So, now, the different types of the well that

I have been explained then the components of the well in other shape of the well. Now, first that one is call the circular shape

of the shape of the well or circular well. So, this is type of well that is circular

well. So, next one well can be in this form. So, this is double D well now will can be

in this form also, this is dumb bell dumb well form of well now will can be in this

form also where this is the circular dredge whole. Now,

it can be in this form also these are the circular dredge hole and this is octagonal

shape. So, this is also circular dredge hole and this is octagonal or double octagonal

shape. So, these are the variation in shape of the well. So, depending upon the recumbent

we have to go for different types of well now the when we construct well you have to

deep in mind that the staining thickness should be sufficient. So, that it can be easily sink

into the well and then the dredge hole should be large enough to permit the dredging.

So, when another condition is the when you construct the dredge hole that should be large

enough and the base of the structure should be sufficiently stable and the size is sufficient

to transfers the load. So, these conditions we have to taken care when we construct the

well. So, next one that will go for that how we have, we have to calculate the depth of

the well now this if you summarize the other parts then, then you are different types of

well foundation. And this types are in the open well then the box type of well. And in

the third one is the pneumatic well so when you construct this type of well foundation.

So, you have 2 very careful then this, the base the base that you have to construct there

should be sufficiently rigid. And then that should sufficiently transfer the load from

the superstructures to the foundation soil. And then depending upon the different types

of well then you have 2 construct the, for various different form and various purpose.

And when these other weights various components that will also be designed during the construction

of the well the next we have 2, determine the, what would be the required depth of the

well foundation? And how we calculate the depth of the well foundation because the well

foundation when you construct in a, for a river way. Then you have 2 very careful for

the scoring effect because that will play a very important role. Then what would be

the grip plane below the foundation, below the score level than what with the minimum

thickness of the, of the minimum depth of the foundation that you have to be very carefully

design now, the next part that is the depth of the foundation. So, in any construct the depth of the foundation

as I mentioned the scoring depth in a play very important role. So, that then this scour

depth, how we calculate this scour depth? Because this scour depth means that during

this flow of the water some soil will be taken out by the flow. Then you have the, consider

this covering during our design. So, this scour depth you can calculate that d is scour

depth is equal to 0.473 root 3 q y f know where the the, this is b; this scour depth

is below H F L l I high flag level. Now, here q is equal to design discharge that is meter

cube per second and f is called as lacey’s sift factor

that is 1.76 root to the power m where m is

equal to mean

size of particles in mille meter now this when. So, how will calculate the design discharge?

So design discharge will calculate so, that is given parameters so that you have to first

determine over from the P V S history of the site that is you have to give input to calculate

the scour depth. So, that maximum discharge oh maximum design

discharge that you have to consider. And then this is less sealed function you will calculate

then how will calculate the m? So, that means the particle size of that area so that means

soil you have to collect the soil sample for the required depth. And then form this soil

sample you have to go for particle distribution analysis. So, that you can soil distribution

analysis that depending upon which type of soil it is soil will go for the analysis or

have to go for the analysis. So, we have the gain stain distribution curves so once you

have the gain stain distribution scour then form that gain stain distribution scour we

can determine. What would be the n value that once you get that gain size distribution curve

than we have the gain size distribution. So, that means here if I draw the gain size distribution

scour. So, this is the particle size

which is mille meter so that is in the large

scale and this is the person y fimer. So, we have this type of curve will get so that

is the gain size distribution curve and form this gain size distribution curve. We have

calculate the mean size of particles in what is the mean size of this particle and we can

take weighted average of this particle size. So, there will be basically particle size

and from there we calculate what is the, of the particle size of these that area? And

from that particular size that will be use as the n value. And then form using that n

value we can calculate what could be the field factor f? So, this, these design picture as

a input f we can calculate this on the particular distribution curve or that we have to done

by in the particular distribution analysis. And from that is we can determine the m value

and then from that m value will determine the f and from there he will get the scour

depth scour depth is the required. Now, once we get the scour depth then another line that

is the required is that. The grip length and now grip length is generally

given by one third of d max, d max means

maximum scour depth. Now, could into the highest score that, that this d max should not be

less than 2 meter for piers and abutment with arches? Or I mean this grip plane that should

not be less than 2 meter for piers and abutments with arches. And that should not be less than

1.2 meter for and abutment with other structures. Now, this d max is the maximum scour depth

were what will be the maximum score depth that high score also recommends some values.

That means that the grip line that we have to provide additional that is one third of

the d max. Now for the d max I score that I s 3955, 1967 that recommends some maximum

scour depth of the scour value. And that depends on the different types of the section of the

river in straight section

that this maximum d max is given the 1.27 of d. So d given that is the scour depth that

we have calculate and this is d max. Similarly, for a moderate bend

is values given by the 1.5 d. So, first severe

bend this is 1.75 d for right angle bend that is given 2 d. So, depending upon the

C P C state section then this will be. So, that the source that is taking is Ranjan and

Rao 2000 book. So, now in the state portion if the section state then we have to provide

d max value is 1.27 d and the for the moderate bend we have to provide d max is 0.5 d and

for severe bend so that which 1.75 d and right angle bend 2 d. So, depending upon the section

of the rivyar how much t you have to consider? So, that we can calculate so from this one,

we can calculate that the d max. And then we have 2 d we have to collect the scour depth

and the seal factor does mentioned. So, for depending once we can one process we can determine

the f value from the laboratory test. So, what would be the f value that we can

determine from the laboratory test as I explain? Then distribution analysis you can determine

the f value where you can determine the n value. And from that m you can determine the

f value another option that for different tables available tables are available for

different types of soil, what would be the f value? So, that we can also use at better

is we can test the soil from that the area from the sight. And from that testing data,

we can determine the, what would be the m value, based on that we can determine the

f value. So, f value we can determine and from there we can determine d value and from

this difference type of section we can determine the d max value. And then d max is generally

various 1.27 times to 1.2.75. And then from there we can determine the grip line that

the grip plane will be one third of the d max now, what is the minimum depth of the

foundation? So, that it is recommend again highest recommend that when the minimum. Depth of foundation is 1.33 times of d max

below H F L. So, once we have the d maximum, what will be the mix minimum depths of the

foundation that we have to add with the foundation with the depth of the foundation? So, that

means the minimum depth of the foundation will be has one third is a grip line. So,

that will be a 1.33 times of d max so below the high flag level. So, once we get the d

max or depth of the foundation so depth in a minimum depth of the foundation is the D

so that is or depth of the foundation. So, this is D is the depth of the foundation

of the well then at depth, what would be the

load carrying allowable load carrying capacity of the soil? So, for these highest 3955, 1976

they proposed that this will be the depth of the foundation. So, that is at 5.4 N squares

B plus 1600 plus N squire into D so by which we can determine, what is the allowable load

carrying capacity of the soil at depth of the foundation D? Now wave this Q a is the

allowable load carrying capacity so which is given in kg per meters kg per

meter square; this is kg per meter squire. And then the B is given that the smallest

diameter of the well meter of well section in meters. And D is the depth of the foundation,

foundation below scour level so that is in meter an here a in is corrected S P T value.

So, if I know that this b section and this n is the collected s p t value. And then we

can determine, what would be the allowable load carrying capacity of the soil at the

depth d below the scour level? Now and then we can use that whether the load which is

coming on the soil is greater than q a or not. And then apply and then we have to apply

the factor allowable safety and then you have to check whether the load which is coming

on the soil which is greater than of this load or not. Then if it is greater than you

have to again redesigned this thing for the for that particular soil and that date. So,

and this way we can determining what would be the depth of the foundation? We can determine

the required depth of the well foundation. And at depth what would be the bearing capacity

of the soil? And then we have to check during the design,

this b n capacity of the soil is good enough to resist the load which is coming from the

structure and then now. So again, mentioned that you have to design these components very

accurately because we have some different components of the well foundation. And then

when we are constructing the well foundation there should be a lateral load which is coming

from the in terms of water pressures for that means these things you have to consider during

the design. Because this q way that I mentioned that is a bearing capacity, but when you design

the total well foundation then you have to design some other components of load. That

is the water pressure will come that may act during the like of this well so that in that

state load. Then the, those load, load that will come

during the construction; during the lifetime of this well so that means you have to consider

all these things during the design of the well. So that means this only the bearing

capacity calculation that is not enough to design proper different components of the

well. So that is the bearing capacity that will give whether fine this load which is

coming on the soil which is capable this soil can take that load or not at that depth. So

and depending upon the site conditions we have 2 then increase the load if it is not

sufficient increase the depth of the well if the it is not sufficient to carry that

load at that required depth. Now, the forces of different forces that is acting on that

acting on the well foundations so that difference forces if all. So, this forces includes that the wind force

that act on the well foundation wind forces then the seismic force. Then forces due to

the water current, current then the forces due to the buoyancy

then force due to the temperature variation

in the next, the force due to the earth pressure. So, these are the force is generally acting

in well foundation and definitely the traffic force

load that is acting on the well foundation

in, in additional to that is it is in the. Then the 7 centrifugal force will also act

into the well foundation. So, when you design this well foundation you have to consider

all this forces which are acting on the well foundation during design. And this lateral

earth pressure this earth pressure is basically the lateral earth pressure which is acting

on the well foundation due to the soil surrounded by the well.

Now, when this all combination of force we have to apply and then based on then we can

calculate what would be the net horizontal force that is acting on the well? What is

the moment that is acting on the base of the well? Then what is the vertical or downward

force that is acting on the well including the sellpite of the well? So, these force

is we have to, to be considered during the design of a well foundation. Now, in discuss

have also discuss about the dimension part then the depth part. And now this forces you

have to consider during the design and now the design methodology that are available.

So, that is basically there are few methods that is available. One is Terzequi method.

So, another is first method for the design when we are talking about the design of a

well foundation. Then we have talking about the, a lateral stability of the well so what

how we can check whether the well is stable and the lateral force or the combination of

force or a force of moment whether there well is stable or not so, this lateral stability

of this well. Well we have to check whether this well is

stable or not. Now, the different analysis are available that is for the Terzequi analysis.

Then the Pender’s analysis

then Benerjee and Gangopadhyay’s analysis and I R C also echomin one design or lateral

stability check methodology and that is I R C 45, 1972. So, the by using these methods

we can check whether the well which is laterally stable or not. And that among this methodology

discussed about this I R C method and that will be discuss in the next class. Then how

we can check the lateral stability of the well? How we can check then because this lateral

stability are basically formed moment that is coming. So, that means the registry moment

that should be greater than the moment which is acting on the well, base of the well. And

an another check that the bearing capacity check that means the load which is acting

or the stress which is acting on the soil, soil should will to carry that stress. So,

that is the, we have to check whether that moment which is applied in the well that should

be a counterbalance by the well foundation. So, that means that is one check moment, check

another one the that soil pressure that is sufficient the, the soil pressure which is

coming on the soil so that is soil is sufficient to carry that load. And then we have to check

another condition the way of horizontal force which is acting. So, that means the, that

should be a counterbalance or resisting force we have to that is sufficient to counterbalance

that horizontal force. That means have to check whether horizontal force which is horizontal

force checking how to check for the moment which is acting. And have check whether soil

pressure acting on the base of the soil which is sufficient or not. So, when we design or

we check all this things then after this checking of this well foundation you can say now this

dimension we can provide for this particular conditions.

So, first we have to consider this load or combination of loads. And then based on that

we consider what the net horizontal pressure our force, what is the moment net moment acting

on the base of the well? And then based on that we have to consider the, what is the

vertical force that is acting on the well? So, vertical force horizontal force and then

the moment that is acting on the base those we have to calculate. And then we have to

check whether this things soil can able to take thus vertical stress acting on the soil

that is able to take on oil is able to take or not certain. That means the check that

is we have to consider that for this purpose that what are the check that is the first

check is if the summation of the vertical force. And the next one is summation of the

horizontal force and the next one summation of the moment.

So, we have to check all these 3 things that means that this; this is the total down word

or

force that is including the base reaction and side friction. Then W H is the net lateral

earth pressure including

section that can be a side and base and net one in the summation of the moment including

the lateral earth pressure and the friction side and the base. So, these are the force

or that the 3 equilibrium condition sigma V vertical force summation of the horizontal

force. And the summation of the moment that you have to check and according to that you

have to check whether the well can a resist these horizontal force. And the soil can resist

this vertical force or the stress which acting on the soil and the moment which is acting

on the well.

thanks..very good lecture.helps me a lot

very nice sir g

sir you have a Hindi video about civil engineering & construction.

exp. pile fundashion ,well sinking,Pape line works

thanks & regards

Wastage of time. Try to make short and effective, instead of writing each and every line with streaming

sir can you help us discussing ifs agricultural engineering question paper with answer

Not effective

very effective in knowledge building..thanks

Sir please Hindi Mai bhi ek video dalao well foundation kee

Nice video

Box type v.r.b par bhi video upload kare badi maherbani hogi sir

Thank u for this video sir,explainatiin is very clear and easy to understand

How to calculate well foundation bottom plug quantity of concrete

Cha very bad

Go first and sleep then teach any one

Nice work sir ! M not the one who will make any negative cmmnt after getting a valuable information from u ! U did it for free nd some people even after knowing this try to make negative cmmnts that, ur sound is not good etc ,, keep going sir nd help the engineers as most of the colleges in india is having lack in faculties !

Teri maa ki chuut

Aise pdate hai

Dekh dekh ke sab bol rha hai……Yeh toh koi chota bcha bhi krle

Sir plz make a video of depth of well foundation

Plzz make this video as soon as possible

Sir i am getting a problem in site that if the angle of well curb is 67 degree it will effect on well sinking?

Sir how to make bbs of well foundation

try to make it short…as u copied everything from gopalranjan textbook (every line was copied)..too bad..

Not effective…

Sorry to comment. The lecture is monotonous and ineffective. Wasting time. Make brief and practical one. You are just following one textbook and giving lecture. Language is poor too.

Ineffective lecture

Hindi mein kuyn nehi banate.Faltu ka English bloke theory ko complicated bana dia.

You are wrong in pneumatic well

The top portion is closed and bottom is open