Design of Steel Structures Questions and Answers - Bolted Connections

1. What is the yield strength of bolt of class 4.6?
a) 400 N/mm2
b) 240 N/mm2
c) 250 N/mm2
d) 500 N/mm2

  Discussion

Answer: b
Explanation: For class 4.6, ultimate strength = 4×100 = 400 N/mm2
yield strength / ultimate strength = 0.6
yield strength = 0.6×400 = 240 N/mm2.

2. Which of the following is correct?
a) size of hole = nominal diameter of fastener – clearances
b) size of hole = nominal diameter of fastener x clearances
c) size of hole = nominal diameter of fastener / clearances
d) size of hole = nominal diameter of fastener + clearances

  Discussion

Answer: d
Explanation: Size of hole = nominal diameter of fastener + clearances
Clearance may be standard size, oversize, short slotted or long slotted.

3. High strength bolt is used for ____________
a) shear connection
b) slip resistant connection only
c) bearing type connection only
d) both slip resistant and bearing type connection

  Discussion

Answer: d
Explanation: High strength bolt may be used for slip resistant and bearing type connection. At serviceability, HSFG bolts do not slip and the joints are called slip resistant connections. At ultimate load, HSFG bolts do not slip and the joints behave like bearing type connections.

4. Which of the following is advantage of HSFG bolts over bearing type bolts?
a) joints are not rigid
b) bolts are subjected to shearing and bearing stresses
c) high strength fatigue
d) low static strength

  Discussion

Answer: c
Explanation: The advantages of HSFG bolts over bearing type bolts are : (i) joints are rigid, (ii) bolts are not subjected to shearing and bearing stresses as load transfer is mainly due to friction, (iii) high static strength due to high frictional resistance, (iv) high strength fatigue since nuts are prevented from loosening, (v)smaller number of bolts results into smaller number of gusset plates.

5. Which of the following is correct for pitch of the bolts and gauge?
a) pitch is measured along direction of load, gauge is measured perpendicular to direction of load
b) pitch is measured perpendicular direction of load, gauge is measured along to direction of load
c) pitch is measured along direction of load, gauge is measured along to direction of load
d) pitch is measured perpendicular direction of load, gauge is measured perpendicular to direction of load

  Discussion

Answer: a
Explanation: Pitch is centre to centre spacing of bolts in a row, measured along direction of load. Gauge is the distance between two consecutive bolts of adjacent row measured at right angles to the direction of load.

6. What is the minimum pitch distance?
a) 2.0 x nominal diameter of fastener
b) 3.0 x nominal diameter of fastener
c) 1.5 x nominal diameter of fastener
d) 2.5 x nominal diameter of fastener

  Discussion

Answer: d
Explanation: Pitch is centre to centre spacing of bolts in a row, measured along direction of load. Distance between centre to centre of fasteners shall not be more than 2.5 times nominal diameter of fasteners.

7. Maximum pitch distance = ______________
a) 16 x thickness of thinner plate
b) 32 x thickness of thinner plate
c) 40 x thickness of thinner plate
d) 20 x thickness of thinner plate

  Discussion

Answer: b
Explanation: Distance between centre of any two adjacent fasteners shall not exceed 32t or 300mm, whichever is less where t is thickness of thinner plate.

8. Pitch shall not be more than ___ in tension member and _______ in compression member.
a) 12t, 16t, where t = thickness of thinner plate
b) 20t, 16t, where t = thickness of thinner plate
c) 16t, 12t, where t = thickness of thinner plate
d) 16t, 20t, where t = thickness of thinner plate

  Discussion

Answer: c
Explanation: Pitch shall not be more than 16t or 200mm, whichever is less in tension member where t is thickness of thinner plate. Pitch shall not be more than 12t or 200mm, whichever is less in compression member, where t is thickness of thinner plate.

9. In case of staggered pitch, pitch may be increased by ______
a) 50%
b) 20%
c) 100%
d) 30%

  Discussion

Answer: a
Explanation: Spacing between centres of fasteners may be increased by 50% when fasteners are staggered at equal interval and gauge does not exceed at 75mm, subjected to maximum spacing condition.

10. What is the difference between end and edge distance?
a) Edge distance is measured parallel to direction of stress, while end distance is measured perpendicular to direction of stress
b) Edge distance is measured parallel to direction of stress, while end distance is measured parallel to direction of stress
c) Edge distance is measured perpendicular to direction of stress, while end distance is measured perpendicular to direction of stress
d) Edge distance is measured perpendicular to direction of stress, while end distance is measured parallel to direction of stress

  Discussion

Answer: d
Explanation: Edge distance is distance at right angles to the direction of stress from centre of hole to adjacent edge. End distance is distance in the direction of stress from centre of hole to end of element.