 Hi everyone. Myself Supriya Pasnu working as an assistant professor in civil department from Walton Institute of Technology, Solaapur. Today's class we are going to discuss the design of the dog legs staircase. We are going to discuss the dog legs staircase. So these are the learning outcomes. At the end of this session students will be able to draw the neat drawings of different building components such as the doors, the windows and the staircases. So there are different types of the building components. So out of this we are going to discuss about the staircase. So staircase also there are different types such as the dog legs staircase, the simple staircase that is the straight staircase, open well staircase, bifurcated staircase. So among all these types we are going to discuss about the dog legs staircase. So the dog legs staircase they are used in the residential buildings, the commercial buildings, any type of the public buildings. So this is the data which is provided. The staircase block size is given to you as 2 meter by 4.6 meter. So note that all the dimensions they are in meters and the scale which is used is 1 is to 30. You are supposed to draw the staircase using the mini drafter. So here I am using the normal scale. So using the mini drafter itself is needed to draw the staircase block. So the staircase size is given to you as 2 meter by 4.6 meter and the floor to floor height is given to you as 3.2 meter. So let us consider that this is a public building. So let we will assume the size of the riser as 15 centimeter. So as it is a public building. So depending upon the size of the riser you can find the number of the risers that is the height of each floor divided by the size of the riser. So height of each floor means you are going to design a dog leg staircase. So there are two floors that is the, you have the floor to floor height that is 3.2 meter. So divide it by 2 you get 1.6 meter. So this is how the number of the risers you will be finding as height of each floor divided by the size of the riser that is overall you get 10.66. Then round it off you get 11 number of the risers. So note that number of trades are less than number of risers. So let us assume the trade size is 25 centimeter. So number of trades will be number of risers minus 1. That is number of risers are 11 minus 1. This is 10 that is number of trades are 10. So as you have the size of the riser and number of trades you can find out the space occupied by the trades. As you have the size of the block with you that is the length of the block is 4.6 meter. So let us see what is the space occupied by the trades. So 25 way is the size of the riser and number of the trades is 10. So likewise you get 250 centimeter the space occupied. So let us see what is the width of the stair. So as you have the width of the staircase block as 2 meter. So let us take that the landing width will be 1 meter. So the landing width is always equal to the width of the stair. So width of the stair will be also 1 meter and the landing width will be 1 meter. So let us see what is the space left for the passage. As you have the length of the block as 4.6 meter. So 4.6 meter minus 1 meter is the landing slab and minus the space occupied by the trades. So likewise you get the space left for the passage it is 1.1 meter. So from that you have only the staircase block size with you. So let us assume the thickness of the wall as 20 centimeter. So these are the sizes of the openings that is the door opening and the window opening. So the door size is 1.2 meter by 2.1 meter. 1.2 meter is the width of the door whereas the 2.1 meter is the height of the door. So when you draw the plan of the staircase over there the width of the door will be visible to you. Likewise the height of the door will be seen in the sectional elevation. So the window size overall is 1.2 meter by 1.2 that is the size height and the width is same. It is a square window. So depending you have to first of all design this staircase depending upon the data which is given to you. Decider the number of the risers and the number of the trades from that you are going to design the staircase block. So this is the dog leg staircase. So first of all the internal that is the clear block size is given to you. That is 2 meter is the width of the block and 4.6 meter is the length of the block. So you have to convert it into scale. The scale is taken as 1 is to 30. So as they are in meters first of all convert it into centimeter. That is 2 meter means in 200 it will be in centimeter that is 200 centimeter. So divided by the scale what is given to you as 30. So according to that you are going to get the dimension of this convert it into 1 is to 30. All the dimensions whatever they are available you have to convert it into scale and using the mini drafter you are going to draw this drawing. So this width is taken as 2 meter and then 4.6 meter is the length. Now the staircase the clear staircase block is drawn and then you have the width of the staircase block that is the thickness of the wall the thickness of the wall is given to you as 20 centimeter. So take the overall thickness of the wall for all the four corners of for all the four sides of the block and then using this the staircase block is completed now. Then you have to decide where the door to be placed. So in front of the staircase block that is in front of the straight one of the flight the door is placed that is around from the corner you have to leave a 20 centimeter gap and then place the door over here and the window it is centrally placed in one of the side of the staircase block. The staircase block size is given to you as 1.2 meter. So this is the width 1.2 meter which is seen from the top view of that and the overall height of the window will be seen in the elevation. So this here is the width of the door taken which is 1.2 meter. So now you have the width of the flight that the width of the staircase block it is 2 meter. So you have the landing slab, landing width it is taken as 1 meter. So just divide it into two parts you get the landing of 1 meter that is nothing but the width of the staircase. So here you have to take two flights as it is a dog-like staircase and then decide the space occupied. First of all you are going to take the size of the landing that is 1 meter. So from this corner itself draw the 1 meter gap this is the landing and let's see what is the space occupied by the trade it is 2.5 meters only. So then from this you have to take 2.5 meter draw the second vertical line. So this is what the space occupied by the trades is and then remaining part will be the passage which is left as 1.1 meter. So this is how the overall length of the staircase block is drawn. So now you have this size of the trade which is given to you as 25 centimeter. So convert it into scale and then draw the size of the trade that is overall you have 10 trades. So in the top view when you see a staircase block trades will be visible to you whereas in the sectional elevation you have the risers and the trades both that is a step. Step includes both the riser and the trade. So here you are going to draw 10 trades in a single flight. So here after climbing the staircase you have a landing over here where you rest for some time and then have a change in the direction which leads to the first floor. So this is the ground floor and this is the first floor which leads to the first floor. So likewise this is the staircase block. So now to draw the sectional elevation that is the sectional view xx draw the sectional line over here xx then take all the projections whatever they are available that is this corner the wall thickness over here at the two corners you have to take the wall thickness and then take the projections of all the trades. So now this is the floor level sectional view first of all you have the floor level that is the ground floor level and then this is the projection of the trade which is taken. So while starting here you immediately don't start with the trade itself. So before the trade you have the riser over them. So the riser size is given to you as 15 centimetre. So using the mini drafter draw the height of the riser that is 15 centimetre and then draw the trade. This trade is nothing but the top view of this. So this is how the trade and the risers are drawn using these projections. After drawing this trade you have to take again the projections of the riser and then again the trade. So likewise here 10 number of trades are to be drawn and then this is the after this is the last trade where it ends. So after that you have the landing slab over here. So this is what the landing slab is drawn over here this is the landing slab and then immediately after this you have a change in the direction. This is the second flight over here. So to climb the second flight also instead of starting from the trade itself you have to start with the riser. So that is what the number of the risers are more than the number of the trades. So first of all you have the riser and then again the trade is there. So likewise this is the elevation of the complete staircase. So for these steps to support that you have the vertical members that is called as the balusters and to the balusters to support all the balusters you have the handrail. So that a person can easily climb easily. So for this handrail and the balusters you have the nevel posts. Nevel posts are provided at the top and the bottom member of the staircase block. So here you can see after the landing slab at a height of 0.6 meter a window is placed. Window height is 1.2 meter as it is given in the data. So this is how the window is placed over here. It won't be placed immediately after the landing slab itself. So after a height of 0.6 meter you have to place the window over here. So the nevel post height is around 0.9 meter. The nevel post height is around 0.9 meter. You have to take 0.9 meter over here and this is also 0.9 meter. So likewise join these two vertical lines you get an inclined slab. So over here the parallel to that you have an inclined slab over here also that is called as the waist slab. So this is the inclined line to draw that you have to take the pitch of the angle that is it will be around 25 degrees. So this is how the inclined slab is drawn. So it will be parallel to the line of the nosing. So likewise the same the second flight also the inclined slab has to be drawn. So here you can check that this flight it leads to the first floor. So likewise calculate the height from the first floor to the ground floor. That will be around 3.2 meter which is given. So likewise this is how the dogleg staircase elevation is drawn including all the members of the staircase that is the riser, the tray, the handrail, balusters and the nevel post. And this is the waist slab which is around 15 centimeter thickness. So this is the concrete shown in that. So this is how the dogleg staircase has to be drawn. So here are the MCQs. In dash all steps lead in one direction only. First option turning steps, second is the circular steps, third is the straight steps, fourth is the geometrical steps. So you have got the answer for this. This is the answer. These are the references. Thank you.