Open Web Trusses vs. Rigid Frames

Whether you’re building a warehouse, barn, manufacturing plant, or workshop, there are different structures to depend on. To realize your vision, you must choose between different styles of structural frameworks. Open web truss and rigid frame designs are examples of popular options.

So, when it comes to frames vs. trusses, what’s the better choice? Let’s look at the options.

What Are Open Web Trusses?

Open web truss frames consist of two parallel chords connected by diagonal and vertical triangulated members. The frames resemble ladders, except diagonal members replace horizontal rungs. Unlike other framing structures, open web trusses do not typically have cross ties — the triangulation of the diagonal members provides the necessary support and stability.

Trusses carry heavy loads, such as the weight of roofs, bridges, and floors. The placement of the diagonal and vertical members allows the structure’s weight to be evenly distributed. Even weight distribution means that open web trusses provide more stable support than traditional roof beams. Additionally, these structures don’t require any extra support beams, so you’ll have an abundance of free-span space beneath the roof for equipment. A further benefit of this type of framing is its ability to prevent wind from lifting the fabric roofing membrane. By keeping the roofing secure, there is less chance of damage to the structure and the equipment inside.

Open truss designs are lightweight because they use fewer materials. However, despite being lightweight, the materials still provide excellent strength and stability for your building needs. A lightweight design also decreases the materials you need when constructing buildings and makes building easier and more manageable.

What Are Rigid Frames?

Regarding strength and design, rigid frames and open trusses are similar. However, rigid frames have vertical columns that support horizontal beams. These structures benefit buildings that require stability against vertical and lateral loads. For example, the frames are ideal for multistory commercial, industrial, and retail operations. They’re also a good solution for areas that experience high winds.

These frames typically do not require support beams, so they also support a free-span interior, benefitting manufacturing warehouses, agricultural businesses, and other buildings where you need wide-open space, whether to store equipment, park large vehicles, or operate production lines. You will have much usable and open space per square foot.

These durable frames also offer a simple design, making them easy to build and possibly leading to quicker construction. This translates to cost savings.

Differences Between Trusses vs. Frames

To decide between open web trusses and rigid frames, you must understand their similarities and differences. We’ll look at some of the areas where the two differ.

Building Size, Type, and Location

Historically, rigid frames were the preferred option for larger buildings. However, technology advancements make open web truss structures just as effective for expansive buildings, even those 250 feet wide and over 1000 feet long.

Rigid frame structures support a free-span interior, so they make excellent warehouses and manufacturing plants. Their box-like construction also means they support multiple stories.

Because of their versatility, open web trusses are an option anywhere — from agricultural to industrial areas. They make fantastic garages and workshops. Like rigid frame structures, they do not require support beams and are great when you want a wide-open space. Open web trusses also allow for the addition of extra height via custom end walls and sidewalls.

Budget

Open web truss buildings and rigid frame buildings have comparable costs. However, in most cases, open web truss structures are more affordable, while rigid frame structures have a higher price tag. The reason behind this is rigid frames rely on steel thickness for strength, while open web trusses get more strength with fewer materials, thanks to their unique design. Because they’re made with fewer materials, open web trusses are generally lighter and provide a better cost-to-strength ratio. Additionally, they stand up to greater snow loads.

Weather Conditions

Both of these structures provide excellent weather protection. Steel withstands extreme weather conditions — from torrential rain and heavy snowfall to wind, fire, debris, and low-magnitude earthquakes. In some instances, steel buildings withstand some hurricanes. Rigid frame structures are resilient against high winds, and open web trusses are also able to withstand harsh weather, including snow and wind. Open web trusses with reliable fabric can handle more than 300 pounds of snow per square foot.

Strength

Both of these structures offer impressive durability. Rigid frames withstand intense weather because of the thicker steel, and fabric structures are custom-engineered for the environment, enabling them to withstand winds exceeding 150 miles per hour (mph). Open web trusses also offer enhanced stability in addition to strength because of the triangulated members, which is why they’re used across industries in various areas.

Engineers analyze multiple configurations to determine the best truss components for load-bearing strength, fabrication cost economy, and a pleasing appearance. Open web trusses regularly outperform other truss designs pound-for-pound for carrying and effectively transferring loads.

Both open web trusses and rigid frames are made corrosion- and rust-resistant through hot-dip galvanization — the components get immersed in a bath of molten zinc. The zinc coating helps the steel become corrosion- and rust-resistant, which adds to the longevity and strength of the structure. It’s important to note that the cost per square foot of galvanization is more affordable for open web structures.

Open-web trusses offer an unobstructed view into the frame, allowing for easier wiring, plumbing, and ductwork installation between trusses. Rigid frames are more enclosed, which makes these processes longer and more complicated. The longer processes increase construction costs and require more on-site planning and communication between tradespeople. For example, plumbing tasks must happen at a specific time before or after another project stage, leading to potential disruptions.

Installation

Installation is another factor to consider. Open web trusses are created off-site and delivered to the worksite already constructed, which takes some of the burdens off of your team. Once they’re delivered, you or an installation team are responsible for lifting, placing, and securing them. Installation is efficient and quick, leading to cost savings.

Rigid frame installation is more complicated — the connections must be precise for maximum strength and longevity. Plus, you may need specialized equipment for larger structures.

The Summary: Open Web Trusses vs. Rigid Frames

Both of these structures provide impressive strength and support buildings that require wide open spaces, like warehouses and garages. Rigid frames are often used to construct multistory buildings; whereas open web trusses are typically the more affordable of the two because their unique construction allows them to use fewer materials. Both offer weather protection, ensuring high performance in strong winds and snow.

When it comes to installation, open web trusses are typically the better option. The installation process is simple and efficient, which mirrors the process of wiring, plumbing, and ductwork.

When deciding between these two structural frameworks, ask yourself these questions:

• Do you need a multistory building?
• What is the weather like in the area where the building will be?
• Is the plumbing and wiring complex?
• What is my budget?
• Is efficient installation a priority?
• Will the building have multiple floors?

Partner With Calhoun Super Structure for Your Next Project

Open web trusses and rigid frames provide many benefits, from strength and rust resistance to wide open spaces suitable for many commercial businesses. However, some nuances will help determine which option will work for you.

If you prioritize cost-effectiveness, installation efficiency, stability, and versatility, open web trusses fit the bill. At Calhoun Super Structure, we design, manufacture, and install fabric structures that use hot-dipped galvanized open web trusses. To see how we’ll assist your construction project, contact us today!