3 modes in which bending moments can be induced in a structural member

Full Answer Section

• • A torque applied at a specific point on the member.
  • Unequal support reactions at the ends of the member, creating a twisting force.

• Unequal or Differential Thermal Expansion: If a structural member is subjected to uneven heating or cooling, it can cause different parts of the member to expand or contract at different rates. This thermal expansion mismatch can induce bending moments within the member. This scenario is more common for long structures exposed to significant temperature variations.

Sample Answer

Bending moments in a structural member can be induced in three main ways:

1. Transverse Loads: This is the most common scenario. When a load acts perpendicular (transverse) to the longitudinal axis of the member, it creates a moment that tries to bend the member. Examples include:

   • A concentrated load placed on a beam at a single point.
   • A uniformly distributed load acting over the entire length of the beam (like snow on a roof).
   • A point load acting away from the support point of a cantilever beam (beam fixed at one end).

2. Moment Loads: A moment load is a twisting force applied directly to the member, causing bending. This can be caused by: