Basic structures and load-carrying mechanisms

Structures are categorised into three types: Solid structures, Frame structures, and Shell structures.
Solid structures are made up of solid mass elements like mud forts or snowmen.
Frame structures are made up of struts and ties interconnected to form a structure, examples include bridges or buildings.
Shell structures are those structures that take a hollow form and resist loads, examples include eggshells or dams.

Tension: The force that stretches or elongates a material like in a stretched rubber band.
Compression: The force that shortens or squashes a material, for example, a compressed spring.
Shear: The force that causes layers or sections in a material to slide against each other.
Torsion: The force that twists a material, much like a wringing out a wet cloth.
Bending: The force that causes material to bend like a ruler held down and pushed in the middle.

Dead load: The weight of the permanent parts of the building. This includes the weight of the walls, floors, roof, etc.
Live load: The additional weight added to the structure like people, furniture, machines, etc.
Static load: A load that doesn’t change direction or magnitude.
Dynamic load: Loads that change direction or magnitude, for example, wind or earthquake loads.

Stability: The property of a structure to remain in a state of equilibrium under the influence of different types of loads.
Strength: The ability of a material to resist applied stresses without failure.
Failure: The state when a material or structure cannot withstand the applied forces or displacements and breaks or collapses.
Stiffness: The measure of rigidity in a material. A stiff material tends to deform less under the applied loads.
Ductility: The property of a material that enables it to undergo large deformations and absorb energy before it fractures or breaks.