1. Which of the following is true about torsional buckling?
a) failure occurs by bending about shear centre in longitudinal axis
b) failure occurs when torsional rigidity of member is greater than bending rigidity
c) standard hot rolled shapes are not susceptible to torsional buckling
d) it cannot occur with doubly symmetric cross section
Explanation: In torsional buckling, failure occurs by twisting about shear centre in longitudinal axis. It occurs when torsional rigidity of member is appreciably smaller than bending rigidity. It can occur only with doubly symmetric cross section with very slender cross sectional elements. Standard hot rolled shapes are not susceptible to torsional buckling
2. Which of the following is not a solution for torsional buckling?
a) increasing length of members subjected to torsion
b) by careful arrangement of members
c) by providing bracing to prevent lateral movement and twisting
d) box section fabricated by adding welding side plates to ISHB sections
Explanation: Torsional buckling can be prevented by careful arrangement of members, by providing bracing to prevent lateral movement and twisting. In situations where torsion is expected either a box section fabricated by adding welding side plates to ISHB sections or by shortening box section fabricated by adding welding side plates to ISHB sections becomes the solution.
3. Flexural torsional buckling cannot occur in ________
a) unsymmetrical members
b) cross section with one axis of symmetry
c) cross section with no axis of symmetry
d) doubly symmetric members
Explanation: Flexural torsional buckling is a combination of flexural and torsion buckling. The member bends and twists simultaneously. It can occur only with open sections that have unsymmetrical cross section – both with one axis of symmetry(eg: channels, double angled shapes) and those with no axis of symmetry (eg: unequal leg single angles). Since the shear centre and centroid coincide with each other, doubly symmetric or point symmetric open sections are not subjected to flexural torsional buckling. Close sections are also immune to flexural torsional buckling.
4.What is compression member?
a) structural member subjected to tensile force
b) structural member subjected to compressive force
c) structural member subjected to bending moment
d) structural member subjected to torsion
Explanation: Structural member which is subjected to compressive forces along its axis is called compression member. Compression members are subjected to loads that tend to decrease their lengths.
5. Which of the following is true about axially loaded column?
a) member subjected to bending moment
b) member subjected to axial force and bending moment
c) net end moments are not zero
d) net end moments are zero
Explanation: if the net end moments are zero, the compression member is required to resist load acting concentric to original longitudinal axis of member and is called axially loaded column or simply column
6. Which of the following is true about beam column?
a) member subjected to bending moment
b) member subjected to axial force only
c) member subjected to axial force and bending moment
d) net end moments are zero
Explanation: If the net end moments are not zero, the member will be subjected to axial force and bending moments along its length. Such members are called beam-columns
7. What are columns?
a) vertical compression members in a building supporting floors or girders
b) vertical tension members in a building supporting floors or girders
c) horizontal compression members in a building supporting floors or girders
d) horizontal tension members in a building supporting floors or girders
Explanation: The vertical compression members in a building supporting floors or girders are normally called as columns. They are sometimes called as stanchions. They are subjected to heavy loads. Vertical compression members are sometimes called posts.
8. Which of the following are true about roof trusses?
a) principal rafter are compression members used in buildings
b) principal rafter is bottom chord member of roof truss
c) struts are compression members used in roof trusses
d) struts are tension members used in roof trusses
Explanation: The compression members used in roof trusses and bracings are called as struts. They may be vertical or inclined and normally have small lengths. the top chord members of a roof truss are called principal rafter.
9. Which of the following is not a load on columns in buildings?
a) load from floors
b) load from foundation
c) load from roofs
d) load from walls
Explanation: Axial loading on columns in buildings is due to loads from roofs, floors, and walls transmitted to the column through beams and also due to its own self weight.
10. The strength of column does not depend on
a) width of building
b) material of column
c) cross sectional configuration
d) length of column
Explanation: The strength of column depends on material of column, cross sectional configuration, length of column, support conditions at the ends, residual stresses, imperfections.