RIGID STEEL FRAME BUILDLINGS VS. QUONSET HUTS: CHOOSING THE RIGHT ONE FOR YOUR PROJECT AND BUDGET

When it comes to a choice of building materials for your facility, you already know steel is the most durable of them all. It’s light, requires a smaller foundation than structures built of other materials, and it is a highly versatile material.

Now you need to decide what type of steel structure is best suited to your needs and budget. As you were driving along the highway recently, you probably saw any number of buildings. Among them were structures that were probably built using a rigid steel frame. A few may have been a more identifiable structure: the Quonset hut, a building with a semi-circular cross-section and often covered in corrugated steel panels.

Let's take a look at the differences between a rigid frame and arch frame (Quonset hut).


RIGID STEEL FRAME CONSTRUCTION
Rigid frame gets its name from the rigid connection between the straight or tapered columns and the horizontal beam members. Due to the stiffness of the connection, this type of frame can hold vertical loads even as a skeleton structure.

When a vertical load is applied, the connection maintains enough rotational stability that as the beams rotate the columns rotate with them, maintaining their angular relationships.

The vertical load is picked up by the beams and transferred through the columns to the ground.

Decreased deflection
Decreased internal bending moments
Increased rigidity
Rigid frames can be designed smaller than typical post and beam systems. However, the columns should be designed to be slightly larger than usual to carry both the axial loads and the internal bending moments required for stability.

THE PROS OF RIGID STEEL FRAME BUILDINGS
Aside from excellent structural stability, a rigid frame structure provides the most efficiency in storage space. The usable space continues to the roof; there is little wasted space.

Design flexibility
High vertical load stability
Efficient storage per square foot
Easily expandable
A rigid frame can support a variety of building types. It is a versatile frame with a broad range of design possibilities. You can design anything from a small storage building to a huge opera house using rigid steel frame construction.

It holds up in high winds and, with the right roof design, can shed snow and rain quickly and easily. If you need to enlarge, you merely attach a new module to the back, a lean-to or other addition on the side, or create new stories on top.

Perhaps the most desirable characteristic of all is the ability of a rigid frame building to have large, clear interior spans of unbroken space. It can span hundreds of feet without the need for internal columns, up to 300 feet without the need for extra bracing. With additional bracing, clear span space can be increased even more.

Rigid frame kits come engineer stamped for your specific location.

THE CONS OF RIGID STEEL FRAME
The only real disadvantage of a rigid steel frame is the initial cost, which tends to be slightly higher per square foot than other frame types. As the size of the building increases, the difficulty of construction increases as well.

QUONSET HUT FRAME
The distinctive Quonset huts, also known as arch frame, are semi-cylindrical structures with self-supporting lengths of steel, typically connected in a semi-circular shape. This structure became popular in World War II because it was easy to ship and construct. It also does not require a concrete foundation if wind stability is not an issue.

The arched design allows the structure to shed snow and rain without build-up. It can withstand high winds as well if anchored properly.

THE PROS OF QUONSET HUTS
Besides the ease of shedding snow and the wind resistance, Quonset huts are probably the cheapest steel building option out there. At least, up until it gets to 40 feet by 60 feet, at which point prices equalize with or become higher than rigid steel frame.

Quonset huts also provide open floor space without internal columns.

THE CONS OF QUONSET HUTS
Aside from being cheaper (at smaller sizes) than a rigid frame, about the only thing a Quonset hut has going for it is its unique look. That’s about it, though. Clear span space is limited to 80 feet in comparison to rigid steel frame at 300 feet.

Limited in expansion potential
Limited design potential
Less efficient storage per square foot
A rigid frame can be expanded outward and upward. A Quonset is limited to becoming a longer building.

The curved design that makes arched frame so distinctive also robs it of square footage. There are fewer square feet of storage space in a similarly sized Quonset hut than a rigid steel frame building because the arched roof reduces headroom and roof space. If your storage or other needs are angular, the rounded shape of the Quonset is also less efficient in floor space.

A Quonset hut cannot be built too high and adding stories is out of the question. Another knock against it is the typical warranty. While a rigid steel frame building comes with up to a 50-year warranty, most Quonset huts only have a 30-year warranty. Also, to qualify for the warranty, the Quonset requires a concrete foundation with a large, thick apron.

Only spray insulation can be used in Quonset huts while any type of insulation is appropriate and installation-friendly for rigid frame steel buildings. Finally, Quonset huts do not come engineer stamped for your location. There are no local building codes for this type of structure.


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