In any structure or building, two fundamental forces come into play: tension and compression. These forces act on materials, and each material has its unique capacity to handle them.
When a force pulls a material apart, it’s known as tension. This force tries to stretch the material. For instance, when an object is hung from a rope, gravity pulls on it, attempting to elongate the cord.
Compression is the force that squeezes or shortens materials together. When we push down on a spring, we apply a compression force. This force can act in one direction (uniaxial) or multiple directions (biaxial or triaxial).
Materials experience both tension and compression when they bend. For example, in a beam, the bottom part undergoes tension while the top part experiences compression. The neutral axis in the middle of the beam experiences no stresses during bending.
Both tension and compression forces are critical considerations in structural design. If a material can’t handle these forces, a structure may collapse under dead and live loads. Therefore, all structures must be designed to withstand these forces.
Aspect | Tension | Compression |
---|---|---|
Definition | Pulling material apart | Squeezing material together |
Effect on Material | Tries to stretch material | Tries to shorten material |
Representation | T = mg + ma | N = ma |
Units | Newtons (N) | Newtons (N) |
Stress | Tensile Stress | Compressive Stress |
Strain | Ratio of increase in length to original length | Ratio of reduction in length to original length |
Example | Pulling a rope | Compressing a spring |
Application | Bridges, ropes, cables, etc. | Columns, pillars, beams, etc. |
Critical Failure | Buckling due to excessive compression force | Snapping due to excessive tension force |
Management | Transfer or dissipate force | Transfer or dissipate force |