MAHALAKSHMI ENGINEERING COLLEGE TIRUCHIRAPALLI

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1 MAHALAKSHMI ENGINEERING COLLEGE TIRUCHIRAPALLI QUESTION BANK WITH ANSWER DEPARTMENT: CIVIL SEMESTER: 06 SUBJECT CODE /NAME: CE 2352/DESIGN OF STEEL STRUCTURES YEAR: III UNIT II TENSION MEMBER PART - A (2 marks) 1. Draw any two typical cross sections of tension member using angle sections. (NOV/DEC 11) 2. What is block shear? (NOV/DEC 11) This type of failure is characterized by tearing out of a segment or block of material at the end of a member for certain connection configuration and in coped beams. The block shear failure occurs along a path involving tension on one plane and shear on a perpendicular plane. 3. List out the typical failure modes in tension member. (MAY/JUNE 12) Cross section yielding Net section rupture Block shear failure 4. What is the formula for design strength due to yielding of critical section? (MAY/JUNE 12) 06 Semester Civil CE2352 Design of steel structures. by M.Alaguraj AP / Civil Page 1

2 Where, F y =yield stress of the material A g =gross area of cross section γ mo =partial safety factor 5. List out the different types of bolts. (MAY/JUNE 12) Unfinished bolts (black bolts) Finished bolts (turned bolts) High strength friction grip bolts (HSFC). 6. Define slenderness ratio. (MAY/JUNE 12) Slenderness ratio of a column is defined as the ratio of effective length to corresponding radius of gyration of the section. Thus Slenderness ratio=l e /r Where, l e =effective length r=appropriate radius of gyration 7. What are the various types of tension members? (NOV/DEC 12) Wires and cables Rods and bars Single structural shapes and plates Built up members 8. What is mean by built up members? (NOV/DEC 12) Two or more than two members are used to from built up members. The built up sections may rigid and stiffer than the single shapes. A built up section may be made of two channels placed with a gusset plate in between them. 9. What is net sectional area? The net sectional area of a tension member is the gross sectional area of the member less deduction for holes. 10. Explain the tension member. Tension members are linear members in which axial forces act so as to elongate(stretch) the member. A rope, for example, is a tension member. Tension members carry loads most efficiently, since the entire cross section is subjected to uniform stress. Unlike compression members, they do not fail by buckling. 06 Semester Civil CE2352 Design of steel structures. by M.Alaguraj AP / Civil Page 2

3 Technology Madras 11. Explain Behavior of tension members Since axially loaded tension members are subjected to uniform tensile stress,their load deformation behavior (is similar to the corresponding basic materialstress strain behavior. In the Yield Plateau the load remains constant as the elongation increases to nearly ten times the yield strain. Under further stretching the material shows a smaller increase in tension with elongation, compared to the elastic range. 12. Write note on Load-elongation of tension member Angles under tension, Angles are extensively used as tension members in trusses and bracings. Angles, if axially loaded through centroid, could be designed as in the case of plates. However, usually angles are connected to gusset plates by bolting or welding only one of the two legs. This leads to eccentric tension in the member, causing non-uniform Distribution of stress over the cross section. Further, since the load is applied by Connecting only one leg of the member there is a shear lag locally at the end Connections. 13. How Angle sections eccentrically loaded through gussets plate? The effect of the gusset thickness, and hence the out of plane stiffness of the end connection, on the ultimate tensile strength is not significant. The thickness of the angle has no significant influence on the member strength. The effects of shear lag, and hence the strength reduction, is higher when the ratio of the area of the outstanding leg to the total area of cross-section increases. When the length of the connection (the number of bolts in end connections) increases, the tensile strength increases up to 4 bolts and the effect of further increase in the number of 06 Semester Civil CE2352 Design of steel structures. by M.Alaguraj AP / Civil Page 3

4 bolts, on the tensile strength of the member is not significant. Madras Even double angles connected on opposite sides of a gusset plate experience the effect of shear lag Technology Madras 14. What is a Lug angle? In order to increase the efficiency of the outstanding leg in single angles and to decrease the length of the end connections, sometimes a short length angle at the ends are connected to the gusset and the outstanding leg of the main angle directly, as shown in Fig.. Such angles are referred to as lug angles. Tension member with lug angle Indian Institute of Technology Madras 15. Why Stiffener required in tension members? The tension members, in addition to meeting the design strength requirement, frequently have to be checked for adequate stiffness. The IS: 800 impose the following limitations on the slenderness ratio of members subjected to tension: (a) In the case of members that are normally under tension but may experience compression due to stress reversal caused by wind / earthquake loading l / r =250. (b) In the case of members that are designed for tension but may experience stress reversal for which it is not designed (as in X bracings) l / r =350 (c) In the case of members subjected to tension only. l / r = 400 In the case of rods used as a tension member in X bracings, the slenderness ratio limitation need not be checked for if they are pre-tensioned by using a turn buckler other such arrangement. 16. Different types of tension members? i) Wires and cables ii) Rods and bars iii) Single structural shapes and plates iv) Built-up members 17. Write note on tension member splice When a joint is to be provided in a tension member, then splice plates are used. Splice plates and rivets are designed for the pull required to be transmitted by the tension member. If the tension members are of unequal thickness, then, packing are used to have surfaces of tension members in one level 06 Semester Civil CE2352 Design of steel structures. by M.Alaguraj AP / Civil Page 4

5 18. What is the condition for design strength of a tension member? Design strength due to yielding of gross section. Rupture strength of critical section The block shear. 19. Define tension member splice. If a single piece of required length is not available tension members are spliced to transfer required tension from one piece to another. The strength of the splice plates the bolts/weld connecting them should have strength at least equal to the design load. 20. Define gusset plate. A gusset plate is a plate provided to make connections at the place where more than one member is to be jointed. E.g. joints of truss, truss girders, etc 06 Semester Civil CE2352 Design of steel structures. by M.Alaguraj AP / Civil Page 5

6 PART B (16 MARKS) 1. Determine the design tensile strength of the plate 200mmx12mm with the holes for 16mm diameter bolts as shown in fig. Steel used is of Fe415 grade quality. (NOV/DEC 11) 06 Semester Civil CE2352 Design of steel structures. by M.Alaguraj AP / Civil Page 6

7 2. A single unequal angle ISA 9060, 6mm is connected to a 10mm gusset plates at the ends with 5nos.of 16mm bolts to transfer tension. Determine the design tensile strength of the angle a) If the gusset is connected to 90mm leg. b) If the gusset is connected to 60mm leg. (NOV/DEC 11) 06 Semester Civil CE2352 Design of steel structures. by M.Alaguraj AP / Civil Page 7

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11 3. Determine the design tensile strength of 160x8mm plate with the holes for 16mm bolts as shown in fig. plates are of steel, grade Fe415. (MAY/JUNE 12) 06 Semester Civil CE2352 Design of steel structures. by M.Alaguraj AP / Civil Page 11

12 4. Determine the tensile strength of a roof truss member 2 ISA 9060, 6mm connected to the gusset plate of 8mm plate by 4mm weld as shown in fig. The effective length of weld is 200mm. (MAY/JUNE 12) 06 Semester Civil CE2352 Design of steel structures. by M.Alaguraj AP / Civil Page 12

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14 5. Design a single angle section for a tension member of a roof truss to carry a factored tensile force of 225Kn.the member is subjected to the possible reversal of stress due to the action of wind. The length of the member is 3m.use 20mm shop bolts of grade4.6 for the connection. (MAY/JUNE 12) 06 Semester Civil CE2352 Design of steel structures. by M.Alaguraj AP / Civil Page 14

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17 6.design a double angle tension member connected on each side of a 10mm thick gusset plate, to carry an axial factored load of 375Kn.use 20mm black bolts. Assume shop connection. (MAY/JUNE 12) 06 Semester Civil CE2352 Design of steel structures. by M.Alaguraj AP / Civil Page 17

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19 7. Design a splice to connect a 300x20mm plate with a 300x10mm plate. The design load is 500kn.use 20mm black bolts, fabricated in the shop. (NOV/DEC 12) 06 Semester Civil CE2352 Design of steel structures. by M.Alaguraj AP / Civil Page 19

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21 8. A tension member of a roof truss carries a factored axial tension of 430Kn.design the section and its connection a) Without using lug angle b) Using lug angle (NOV/DEC 12) 06 Semester Civil CE2352 Design of steel structures. by M.Alaguraj AP / Civil Page 21

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25 .9.design a T-section to act as a tension member carrying an axial tension of 220kN. 06 Semester Civil CE2352 Design of steel structures. by M.Alaguraj AP / Civil Page 25

26 10. Design a tension member using a channel section to carry an axial tension of 220kN. 06 Semester Civil CE2352 Design of steel structures. by M.Alaguraj AP / Civil Page 26

27 11. Design a tension member using two angle section to carry 180kN when both angles are connected, i) on both sides of gusset plate, and ii) on the same side of the gusset plate. 06 Semester Civil CE2352 Design of steel structures. by M.Alaguraj AP / Civil Page 27

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