 Hi friends, myself Kaji Syed Shujat. Today we will discuss how to design a tension member. Currently I am working as an assistant professor in civil engineering department, Walshan Institute of Technology, Solapur. At the end of the session, the students will be able to design a tension member. So, before going to tension member, we will see the definition what is the basic meaning of a tension member. So, a structure or a member which is subjected to two pulling forces applied at the ends is called as a tension member. The members and connections are so arranged that eccentricity in connection and bending stresses on the members are not developed. So, we have to ensure that no eccentricity should be developed and due to this, we will get a uniform distribution of the force. So, the stress in such member are assumed to be uniformly distributed over the net section and hence members subjected only to axial tension are supposed to be the most efficient and economical. Now, we will see types of tension member. Basically, there are four categories of tension member. The first one is wires and cables, bars and rods, single structural plates or sections and built up sections. Sections include rolled sections. I will see the design of tension member. Basically, we have to satisfy three criteria. The first one is the design strength due to the gross section yielding or yielding of gross section. So, the strength in gross section yielding is given by TdG is equal to Agfy divided by gamma m0, where Ag is equal to the gross area of the cross section in mm square. Fy is the yield strength of the material in megapascal and gamma m0 is partial safety factor for failure in tension by yielding, which is equal to 1.1. This is the design strength due to yielding of gross section. Another criteria is design strength due to the rupture of critical section. So, there are various sections. The first one is plate. So, for plate, the design strength due to the rupture of critical section, which is given by TdN is equal to 0.9 an Fu divided by gamma m0, where an is equal to net effective area of the member. Fu is the ultimate stress of the material and gamma m1 is nothing but partial safety factor for failure in tension by rupture, which is given by 1.25. So, we will see what is mean by the net effective area and how to calculate the net effective area of the member. The first one is for the plate, which is seen in this figure that two holes are there. So, the net area for the plate section is given by B minus N into dH multiplied by T. Here, in this case, N is equal to 2 because we have we see that there are two holes and dH is the diameter of hole diameter of bolt hole and B is the width of the section. This is the area of net effective area of the section for the plate. If suppose we have diamond or staggered pattern, then we have to calculate the net effective area based on various patterns. So, the very first one is nothing but the zigzag. This is the failure in this case will be along 1, will be along the plane 1, 2, 3, 4, 5, 6, 7. The another one will be 1, 2, 3, 5 and so on. Another will be 1, 2, 3, 5. So, basically we have to see the trial and error method to determine the minimum area, minimum net area. But how to calculate the zigzag pattern, we have the formula that A N is equal to B minus N into dH plus summation of Pi square divided by 4gi into T. Now, here we have considered the pattern of 1, 2, 3, 4, 5, 6, 7. We can see various cases by trial and error method. So, here N is equal to 5. So, A N is equal to B minus N into dH plus we have 2 pitch. So, summation of 2P square divided by 4 gauge, 1, 2, 3, 4 into T. The descriptions of each and every time is given here, dH is the diameter of bolt hole, B is the width, T is the thickness, N is the number of bolt, P is the staggered pitch and G is the gauge length. Now, for the threaded section, we have to calculate by the formula T dN is equal to 0.9 A N F U upon gamma M naught. Here A N is equal to 0.78 Pi by 4 d square. So, net area for the threaded section will be less than Pi by 4 d square. So, we have taken 0.78 Pi by 4 d square where d is the diameter of bolt, nominal diameter of bolt. And gamma M1 is nothing but partial safety factor for failure in tension by rupture. Next is design strength for the angle section. So, for the angle section we have the formula T dN is equal to 0.9 A N C F U divided by gamma M1 plus beta A G naught F I divided by gamma M naught. Now, A N C is the net area of the connected leg, A G naught is the net area of the outstanding leg. F U is the ultimate strength, gamma M1 is the partial safety factor, beta is the correction factor which is given by this formula. Each and every term is given in this figure. So, W is the outstanding length, T is the thickness, F Y is the yield strength, F U is the ultimate strength, B S for so for the bolted connection B S is equal to W plus gauge minus thickness and for the welded connection B S will be equal to W. L is the length of connection, this is the length of connection. So, each and every term for beta is given here. The description is given here and we have another formula for the design of angle section to calculate the rupture strength, preliminary formula for the design. So, T D N is equal to alpha A N F U divided by gamma M naught, here alpha is equal to 0.6 for 1 or 2 volts, it is equal to 0.7 for 3 volts, it is equal to 0.8 for 4 or more volts or equivalent weld length, where A N is nothing but net area of the total cross section, net area for the total cross section. Next A N C is the connected leg, A G naught is the outstanding leg, T is the thickness of the leg. So, for the other section in case we have Sharon section, T section or some other sections, built up sections normally for the channel sections. So, T D N is equal to 0.9 A N C F U divided by gamma M 1 plus beta A G naught F Y divided by gamma M naught. So, beta is calculated based on the shear lag effect, B S is the distance between the farthest edge of the outstanding leg to the nearest bolt or weld line in the connected leg of the cross section. So, this is the formula for other sections, either it may be a channel section etc. Next we will see another type of failure is the design, we have to also check that the our design should be safe in block shear failure. So, the design strength due to block shear failure is given by T D 2 formulas T D B 1 and T D B 2. So, the formula is A V G into F Y divided by root 3 gamma M naught plus 0.9 A A T N F U divided by gamma M 1. So, whichever is less that will be the design strength in block shear failure that each and every term is given A V G is the minimum gross area in shear lag and A V N is equal to minimum net area in shear along a line transmitted by the force. And similarly we have T therefore, tensile gross area and T N for the net area in tension. F U is the ultimate strength, F Y is the yield strength and these are the partial safety factors. This indicates the shear failure, this indicates the tensile failure, this indicates the shear failure, this indicates the tensile failure. And accordingly T D B 1 and T D B 2 whichever is less we will take it as the design strength in block shear failure. The each and every figure explains that. So, for the shear we have the shear plan as 1, 2 and 4, 3 and the tension plane is 2, 3. So, tension plane is this, shear plane is this, here also shear plane is this, tension plane is this. For the bolted connections and for the welded connection, now the design procedure for the tension member is first of all we will calculate the gross area of the section depending upon the factor load. So, A G is equal to T U F Y divided by gamma M naught, we will select a section of gross area, we will increase the gross area by 25 to 40 percent and we will select a section from the steel table and we will calculate the number of bolts and welding length required. Then we will find out the strength in yielding of gross section, then we will find the strength in rupture and then we will find the strength in block shear. So, the strength obtained should be more than factor tension. So, basically the strength obtained in this case should be more than the factor tension, this strength should be more than the factor tension. If it is too much on higher side or it is less than then we have to revise the sections and we have to also check also take a check on as per IS 800 2007 table number 3. So, this is the table number 3, this is a check for slenderness ratio. You can find it in IS table number 3, IS 800 2007 table number 3. So, whatever we have discussed we will see some review questions. The first question is the best suited rolled section for tension member is you can pause the video and answer the question, the T section and the second one is a plate used for connecting two or more structure member intersecting at each on each term as a gusset plate. So, these are my references. Thank you.