What is a Concentrated Load?

A concentrated load is a force applied at a single point on a beam or structure. Beams are commonly used for structural support in homes, commercial buildings, and bridges. A beam must be designed to withstand forces and stress, while minimizing weight, space requirements, and material cost. Incorrectly designed beams can fail prematurely and have catastrophic effects.

A load or force can be either concentrated or distributed. A distributed load is spread out over a large area. It can be uniformly distributed, wherein the amount of force is the same throughout the area to which it is applied; or non-uniform, meaning it is not evenly spread out. A distributed load will influence the design of a beam differently than a concentrated load. A concentrated one can be applied at more than one location on a beam, and multiple loading points may exist on a single beam.

In reality, all loads are applied over some finite area, versus at a single point. When the area is small, it is normally assumed to be a concentrated load, to simplify engineering design calculations. For example, the weight of a person on the end of a diving board would be considered a concentrated type of load, even though the person’s weight is truly distributed over only the area covered by the bottom of his feet.

The two most important characteristics of a concentrated load in beam design are the magnitude of the force and the location where it is applied. How a beam or structure is supported plays an important role in its ability to support this type of load. A concentrated load applied at the center of a long beam, which is supported at both ends, will behave very differently than the same load applied to the end of a cantilevered beam.

A concentrated load can cause a beam to deflect, or bend, when the force is applied. The design and construction of a beam will influence its ability to resist bending when exposed to such weight. The deflection of a beam is a function of its cross-section, how it is supported, the material it is made of, and where the forces are applied. Steel beams are most commonly used in commercial buildings due to their strength and resistance to bending, but beams are also manufactured using other materials, such as wood and aluminum.

Concentrated loads are an important consideration in mechanical engineering and design. Beams and structures are typically designed with a safety factor that allows them to withstand loads or other forces that cannot be predicted in the design. Engineering software is readily available to analyze beams and other structures based on their loading and other design criteria, to ensure that they meet the performance requirements.