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When you think of stirrups, you probably picture cowboys rustling their cattle across the open plains. While that is one application for the word, it has an entirely different meaning when you’re talking about construction. What are stirrups in construction, and what are the different types you might encounter?
What Are Stirrups in Construction?
The stirrups you see in construction are a lot different than those you’ll see hanging from a saddle, but they have much the same purpose — providing stability. In the industry, a stirrup refers to a closed steel loop that adds additional reinforcement to bars and beams in construction to keep them from deforming or collapsing under the project’s weight.
Stirrups come in all sorts of shapes and sizes, depending on the project needs and the shape of the building getting reinforced.
Types of Stirrups in Construction
You may see seven different types of standard construction stirrups on any particular project. They all have three things in common. They must have a 135-degree hook, each hook must be at the proper length and the mandrel — the device that the steel stirrups get bent around — has to be the right size. What do the different types of stirrups look like?
You won’t see single-legged stirrups used very often, but they can be useful when you only need to bind two rods. Instead of a full loop, these single-legged stirrups look more like a flattened U-shape.
Double-legged or two-legged stirrups are some of the most common stirrup configurations in the industry. You need a minimum of four rods to complete this kind of stirrup.
The next step up is the four-legged stirrup, which usually consists of two overlapping stirrups that don’t wrap all the rods. For example, if you have eight rods in two rows of four, the two overlapping stirrups will envelop six rods each, with both wrapping the four in the center.
You can take that same eight-rod design and support it with a six-legged stirrup instead. In this configuration, a single stirrup envelops all eight rods, and additional legs add more support. These extra legs usually stretch between two adjacent rods.
Though the previously described stirrup configurations are for square or rectangular projects, you need a circular stirrup for columns. The stirrup’s exact measurements will vary, depending on the size of the project and the number of rods that require reinforcement.
Helical stirrups get their name from their resemblance to a DNA double helix. Instead of wrapping a perfect circle around the rods, a helical stirrup resembles a spring, providing additional support to primarily circular columns.
7. Lateral Ties
If stirrups aren’t enough to support your project’s needs, you can also add lateral ties. These bars won’t be a complete loop like stirrups, but can provide additional support nonetheless.
The Value of Stirrups in the Construction Industry
From the outside, steel-reinforced concrete might look like an immovable object, but without sufficient stabilization from steel stirrups, it can deform. Even a small amount of deformation can damage the project’s structural integrity, creating a whole host of other problems for contractors to contend with.
Stirrups might look complicated, and many people — even in the industry — aren’t familiar with them, but they are an essential part of any concrete or pile foundation construction. If you’re working with steel-reinforced concrete, understanding stirrups is a vital skill you can’t afford to overlook.