1. Which of the following is true about built up section?
a) Built up members are less rigid than single rolled section
b) Single rolled section are formed to meet required area which cannot be provided by built up members
c) Built up members can be made sufficiently stiff
d) Built up sections are not desirable when stress reversal occurs
Explanation: Built-up members, made up of two or more plates or shapes and connected to act as single member, are formed primarily to meet required area which cannot be provided by single rolled section. Built up members are more rigid because for same area much greater moment of inertia can be obtained than single rolled section. Built up members can be made sufficiently stiff to carry compression and tension thus desirable when stress reversal occurs.
2. What is slenderness ratio of a tension member?
a) ratio of its least radius of gyration to its unsupported length
b) ratio of its unsupported length to its least radius of gyration
c) ratio of its maximum radius of gyration to its unsupported length
d) ratio of its unsupported length to its maximum radius of gyration
Explanation: Slenderness ratio of tension member is ratio of its unsupported length to its least radius of gyration. This limiting slenderness ratio is required in order to prevent undesirable lateral movement or excessive vibration.
3. What is the maximum effective slenderness ratio for a tension member in which stress reversal occurs?
a) 180
b) 200
c) 280
d) 300
Explanation: The maximum effective slenderness ratio for a tension member in which stress reversal occurs due to loads other than wind or seismic forces is 180.
4. What is the maximum effective slenderness ratio for a member subjected to compressive forces resulting only from combination of wind/earthquake actions?
a) 180
b) 200
c) 340
d) 250
Explanation: The maximum effective slenderness ratio for a member subjected to compressive forces resulting only from combination of wind or earthquake actions, such that the deformation of such member does not adversely affect stresses in any part of structure is 250
5. What is the maximum effective slenderness ratio for a member normally acting as a tie in roof truss or a bracing member?
a) 180
b) 200
c) 350
d) 400
Explanation: The maximum effective slenderness ratio for a member normally acting as a tie in roof truss or a bracing member, which is not considered when subject to stress reversal resulting from action of wind or earthquake forces is 350.
6. What is the maximum effective slenderness ratio for members always in tension?
a) 400
b) 200
c) 350
d) 150
Explanation: The maximum effective slenderness ratio for members always in tension other than pre-tensioned members is 400.
7. The limits specified for slenderness ratio are not
a) applicable to cables
b) applicable to angle sections
c) applicable to built-up sections
d) applicable to circular sections
Explanation: The limits specified for slenderness ratio in the IS code are not applicable to cables. They are applicable to angle sections, built-up sections, circular sections.
8. The displacement of tension member under service load is given by
a) PLEAg
b) PLE/Ag
c) PL/EAg
d) P/LEAg
Explanation: The displacement, that is increase in length of tension member, under service load is given by Δ = PL/EAg, where Δ = Elongation of member in mm, P= unfactored axial load in N, L = length of member in mm, E = elastic modulus = 2×105MPa, Ag = gross cross sectional area of member in mm2.
9. What is gross section yielding?
a) considerable deformation of the member in longitudinal direction may take place before it fractures, making the structure unserviceable
b) considerable deformation of the member in longitudinal direction may take place before it fractures, making the structure serviceable
c) considerable deformation of the member in lateral direction may take place before it fractures, making the structure unserviceable
d) considerable deformation of the member in lateral direction may take place before it fractures, making the structure serviceable
Explanation: Tension member without bolt holes can resist loads up to ultimate load without failure. But such a member will deform in longitudinal direction considerably(10-15% of its original length)before fracture and the structure becomes unserviceable.
10. What is net section rupture failure?
a) rupture of member when the cross section reaches yield stress
b) rupture of member when the cross section reaches ultimate stress
c) rupture of member when the cross section reaches less value than yield stress
d) rupture of member when the cross section is reaches very less value than ultimate stress
Explanation: The point adjacent to hole reaches yield stress first when tension member with hole is loaded statically. The stress at that point remains constant and each fibre away from hole progressively reaches yield stress on further loading. With increasing load, deformations continue until finally rupture of member occurs when entire net cross section of member reaches ultimate stress.