Understanding Structural Members Resisting Perpendicular Loads

This question asks to identify a specific type of structural member based on how it resists applied loads. The key characteristics described are that the loads are applied perpendicular to its longitudinal axis, and these loads cause internal bending moments and shear forces within the member. Let's examine the options to see which one fits this description.

Analyzing Different Structural Members

1. Role of a Column

A column is a vertical structural element. Its primary function is to resist loads applied axially along its length (along the longitudinal axis). These loads are typically compressive. While columns can experience some bending, it's usually secondary to their main role of resisting axial compression. Loads perpendicular to the axis are not their primary design consideration.

2. Function of a Tie

A tie is a structural member designed to resist forces that pull it apart, known as tensile forces. These forces act along the member's longitudinal axis. Ties are common in structures like roof trusses and bridges.

3. Purpose of a Strut

A strut is a structural member that resists forces pushing it together, known as compressive forces. Like ties, struts are typically loaded along their longitudinal axis. They are also frequently found in truss systems.

4. Characteristics of a Beam

A beam is a structural element specifically designed to carry loads applied laterally, meaning perpendicular to its longitudinal axis. When a load is applied this way, it causes the beam to deflect or bend. This bending action creates internal bending moments throughout the beam's length. Additionally, these transverse loads result in shear forces acting across the beam's cross-section. Beams are essential components in buildings (like floor joists) and bridges, supporting floors, roofs, and decks.

Identifying the Correct Member

Comparing the functions:

• Columns: Primarily axial compression along the longitudinal axis.
• Ties: Primarily axial tension along the longitudinal axis.
• Struts: Primarily axial compression along the longitudinal axis.
• Beams: Resist loads perpendicular to the longitudinal axis, causing bending moments and shear forces.

The question's description directly matches the definition and primary role of a beam. The emphasis on loads being perpendicular to the longitudinal axis and the resulting bending moments and shear forces are defining characteristics of beam behavior.

Conclusion on Structural Load Resistance

Therefore, the structural member that is primarily designed to resist loads applied perpendicular to its longitudinal axis, thereby experiencing bending moments and shear forces, is the beam.