Structure Supporting Load via Tension

Structures are designed to withstand various types of loads. Some structures primarily resist loads by developing internal forces like tension (pulling apart) or compression (pushing together). The question asks to identify a structure that supports externally applied loads mainly by developing tension within its material.

Analyzing Structural Elements

Let's examine the options provided:

• Arch: An arch is a curved structure typically used to span openings. It primarily supports loads through compression. The load is transferred along the curve of the arch to the abutments at either end. Arches are very efficient in compression but cannot effectively handle tension.
• Shell: Shell structures are thin, curved elements that carry loads through membrane stresses (stretching or compressing within the plane of the shell). While shells can experience both tension and compression, their defining characteristic is the distribution of stress across their curved surface, often involving complex stress states rather than solely tension.
• Cable: A cable is a flexible structural element, typically made of steel wires. Cables can only support loads effectively through tension. They cannot resist compression or significant bending moments. When a load is applied to a cable, it takes the shape that allows the tension force to balance the load. Think of suspension bridges, where the main load-carrying elements are large tensioned cables.
• Plate: Plates are flat structural elements that typically support loads through a combination of in-plane forces (tension or compression) and out-of-plane forces (like bending and shear). They do not primarily rely on tension alone to support external loads.

Identifying the Tension-Resisting Structure

Based on the analysis:

• Cables are uniquely suited to support loads primarily through tension because of their flexibility and inability to resist compression.
• Arches primarily use compression.
• Plates resist loads through bending and shear, along with some in-plane forces.
• Shells use membrane stresses, which can include tension, but it's not their sole or defining characteristic compared to a cable.

Therefore, the structure that supports externally applied load by developing tension in it is a cable.