Classification of Load

A load may be defined as the combined effect of external forces acting on a body.  

The loads may be classified as 

• Dead Load:  It is refer to loads that typically don’t change over time, such as the weights of materials and components of the structure itself (the framing, the flooring material, roofing material, etc.),and the weights of fixed service equipment (plumbing, HVAC, etc.).
  
• Live or Fluctuating Load: It is refer to loads that do, or can, change over time, such as people walking around a building (occupancy) or movable objects such as a flower pot on a deck.   In addition to live loads, what is known as environmental loads are loads that are created naturally by the environment and include wind, snow, seismic, and lateral soil pressures.
• Inertia Load or Forces
• Centrifugal Load or Forces

The other way Load may be classified as

• Tensile Load: This components measures the pulling action perpendicular to the section. A pulling action represents a tensile force that tends to elongate the member.
• Compressive Load: This components measures the pushing action perpendicular to the section. A pushing action represents a compressive force that tends to shorten the member.
  
• Shearing Load: Shear involves applying a load parallel to a plane which caused the material on one side of the plane to want to slide across the material on the other side of the plane.
• Bending Load: Bending involves applying a load in a manner that causes a material to curve and results in compressing the material on one side and stretching it on the other.
• Torsional Load: Torsion is the application of a force that causes twisting in a material. 

Load may also be classified as

• Point or Concentrated Load: A load acting at a point of a beam is known as point or concentrated load.
  
• Uniformly Distributed Load: A load which is spread over a beam in such a way that each unit length is loaded to the same extent, is known as uniformly distributed load.
  
• Uniformly Varying Load: A load which is spread over a beam in such a way that it varies uniformly on each unit length, is known as uniformly varying load. Sometimes, the load is zero at one end and increases uniformly to the other. Such a load is known as Triangular Load.