Loads act on your piping system in many different ways and all of them cause wear and tear over time. The three main types of loading are point loading, distributed loading, and coupled loading. But never fear! These stresses can be reduced or alleviated with pipe supports.
Stresses, or loads, can be applied to a piping system in many different ways. The three main types of loading are point loading, distributed loading, and coupled loading. While these stresses can be reduced or alleviated with pipe supports, it's important to understand how these types of loads differ in the behavior of both the magnitude and location of the applied stresses.
A point, or concentrated, load is a stress or load that is applied to a single point on a material. Point loading concentrates applied stress into a single spot, thereby magnifying the stress that the material experiences. Therefore, a point load should be used only when the structure is light, or in cases where the load the material will experience is light.
A distributed load is a stress or load that is applied over a measurable area and is generally measured per unit length or per unit area. Distributed loads can be described as either uniformly distributed (UDL) or uniformly varying (non-uniformly distributed).
As their name implies, UDLs have a magnitude that is constant across the length or area of the structure. UDL can be converted into point loading by multiplying UDL intensity by the length or area of the load. This equal point load is also known as the Equivalent Concentrated Load (ECL) because this load will act at the center of the area affected by the UDL.
Uniformly varying loads have a magnitude that varies within the affected length or area at a constant rate. There are two types of uniformly varying one dimensional loads – triangular and trapezoidal loading. Triangular loads have a magnitude that is zero at one end of the affected length and increases at a constant rate until the end of the affected length. Trapezoidal loads are generally formed through a combination of UDL and triangular loading. The stress level increases at a constant rate along the length, then is constant, and finally decreases constantly to the end of the affected length.
Coupled loading involves two forces with equal magnitudes acting in parallel but opposite directions on the same affected length and area. If the loads are not perfectly centered (each with the same distance from the axis of rotation), torque will be present and the affected structure will experience rotation. The image at the top of this post is a real-world example of coupled loading that most have experienced first "hand."
While the types of loads experienced by a structure can vary significantly, stresses on a material must always be analyzed with respect to the material’s strength to ensure that the structure will be safe and able to withstand the applied stresses. If that is not the case, stresses can be alleviated by including composite pipe supports within the system or choosing an inherently stronger material.