There are three types of load. These are;
- Point load that is also called as concentrated load.
- Distributed load
- Coupled load
Point load is that load which acts over a small distance. Because of concentration over small distance this load can may be considered as acting on a point. Point load is denoted by P and symbol of point load is arrow heading downward (↓).
Distributed load is that acts over a considerable length or you can say “over a length which is measurable. Distributed load is measured as per unit length.
If a 10k/ft load is acting on a beam having length 10′. Then it can be read as “ten kips of load is acting per foot”. If it is 10′ then total point load acting is 100Kips over the length.
Types of Distributed Load
- Distributed load is further divided into two types.
- Uniformly Distributed load (UDL)
- Uniformly Varying load (Non-uniformly distributed load).
Uniformly Distributed Load (UDL)
Uniformly distributed load is that whose magnitude remains uniform throughout the length. For Example: If 10k/ft load is acting on a beam whose length is 15ft. Then 10k/ft is acting throughout the length of 15ft.
Uniformly distributed load is usually represented by W and is pronounced as intensity of udl over the beam, slab etc.
Uniform Distributed Load To Point Load
Conversion of uniform distributed load to point load is very simple. By simply multiplying the intensity of udl with its loading length. The answer will be the point load which can also be pronounced as Equivalent concentrated load (E.C.L). Concentric because converted load will acts at the center of span length.
Mathematically, it can be write as;
Equivalent Concentrated load = udl intensity(W) x Loading length
Uniformly Varying Load (Non – Uniformly Distributed Load)
It is that load whose magnitude varies along the loading length with a constant rate.
Uniformly varying load is further divided into two types;
- Triangular Load
- Trapezoidal Load
Triangular load is that whose magnitude is zero at one end of span and increases constantly till the 2nd end of the span. As shown in the diagram;
Trapezoidal load is that which is acting on the span length in the form of trapezoid. Trapezoid is generally form with the combination of uniformly distributed load (UDL) and triangular load. As shown in the diagram below;
Coupled load is that in which two equal and opposite forces acts on the same span. The lines of action of both the forces are parallel to each other but opposite in directions. This type of loading creates a couple load.
Coupled load triy to rotate the span in case one load is slightly more than the 2nd load. If force on one end of beam acts upward then same force will acts downwards on the opposite end of beam.
Coupled load is expressed as kip.m, kg.m, N.m, lb.ft etc.