Design of Steel Structures Multiple Choice Questions on “Pin Connections”.
1. What are pin connections?
a) structural members connected by bolts
b) structural members connected by cylindrical pins
c) structural members connected by bolts and pins
d) structural members connected by welding
Answer: b
Clarification: When two structural members are connected by means of cylindrical-shaped pins, the connection is known as pinned connection. It resists horizontal and vertical movement, but not moment.
2. Pin connections are provided when _______ required.
a) hinge joint
b) fixed joint
c) irrotational joint
d) rigid joint
Answer: a
Clarification: Pin connections are provided when hinged joints are required , where zero moments or free rotation is desired and horizontal and vertical movement are not desired.
3. Pins used for the connection _________
a) does not affect secondary stresses
b) increase secondary stresses
c) reduce secondary stresses
d) doubles secondary stresses
Answer: c
Clarification: Pins used for the connection reduce secondary stresses. It serves the same purpose as shank of bolt.
4. Forces acting on pin are ______ those on bolt
a) less than
d) equal to
c) half the force
d) greater than
Answer: d
Clarification: Since only one pin is present in the connection, forces acting on pin are greater than those on bolt.
5. In which of the following cases pin connections are not used?
a) truss bridge girders
b) hinged arches
c) tall buildings
d) diagonal bracing connection
Answer: c
Clarification: Pin connections are used in following cases : (i) truss bridge girders, (ii) hinged arches, (iii)tie rod connection in water tanks, (iv)as diagonal bracing connections in beams and columns, (v)chain-link cables suspension bridges.
6. Shear capacity of pin when rotation is allowed is given by
a) 0.5fypA
b) 0.6fypA
c) 0.7fypA
d) 0.8fypA
Answer: a
Clarification: Shear capacity of pin is given by (i) 0.5fypA, when rotation is required, (ii) 0.6fypA, when rotation is not required, where fyp=design strength of pin, A = cross sectional area of pin.
7. Bearing capacity of pin when rotation is not allowed is given by
a) 0.8fypdt
b) 0.6fypdt
c) 0.7fypdt
d) 1.5fypdt
Answer: d
Clarification: Bearing capacity of pin given by (i) 1.5fypA, when rotation is not required, (ii) 0.8fypdt, when rotation is not required, where fyp=design strength of pin.
8. Moment capcity of pin when rotation is not allowed is given by
a) 0.8fypZ
b) 0.6fypZ
c) 1.5fypZ
d) 2.0fypZ
Answer: c
Clarification: Moment capacity of pin given by (i) 1.5fypZ, when rotation is not required, (ii) 1.0fypdt, when rotation is not required, where fyp=design strength of pin, Z=section modulus of the pin.
9. Members joined by pin connections are separated some distance _____
a) to allow friction
b) to allow for bolt heads
c) to allow bending
d) to allow to be removed
Answer: b
Clarification: Members joined by pin connections are separated some distance (i) to prevent friction, (ii) to allow for bolt heads, if the members are built up, (iii) to facilitate painting.
10. Design of pin connections is primarily governed by
a) shear
b) bending
c) flexure
d) friction
Answer: c
Clarification: Large bending moments are generated since members joined by pin connections are separated some distance. So the pin diameter is generally governed by flexure.