FORCES AND LOADS

When a force acts on a structure, that force becomes a load to the structure. 

A typical load that acts on a structure is it's own self-weight or gravitational force. Your own body weight is a load on your skeleton.

There are basically two types of generic loading on a structure:

•  Permanent load: it doesn't vary over the time (e.g. own weight).

•  Variable load: it varies over the time (e.g. weight of snow).

Stress (internal force) is a force that appears when a structure receives an external force. 

There are typically 5 different types of stress:

    a) Tension
    b) Compression
    c) Shear
    d) Bending
    e) Torsion

TYPES OF STRUCTURES

A structure is a set of elements arranged in an optimum way to support a body or an object.

The structure of an object is the ordely distribution of its essential part. This is what gives the object its shape.

Most large structures are one of the following types: mass, frame, truss, vaulted, shell, geodesic or pneumatic.

In the next  video  you  can see examples of the different  types  of structures.