Industrial facilities such as factories, bulk storage, vehicle depots and workshops need to be flexible. Landing a new contract or expanding the business often puts industrial enterprises in the market for more space—and fast. To find the right building solution for their application, customers or architects need to define the needs and constraints of the new building based on the planned use of the building, as well as the location, conditions, life cycle and lead time, to name a few.
While there are many modular and pre-fab options out there, fabric buildings are a highly flexible solution for a wide variety of applications.
Soil and Foundation
Where can you build? Finding a suitable location for a level concrete pad can be challenging, especially in rural or far-flung mining or logistics operations. According to one steel building vendor, clay, peat and loose backfill are examples of poor soil types for both slab foundations and concrete footings. If you put a heavy building on poor soil, it could sink or shift, jeopardizing the entire investment.
In most cases, builders will recommend that the poor soil is removed and replaced with a better soil, such as packed gravel. If the frost line at your site is deeper, this cost will be higher. Another option is to select a different building site with better soil. Neither option is convenient, and both can add unplanned costs to a project.
Steel framed fabric buildings are lighter-weight than traditional concrete buildings which makes them a better choice when it comes to soil conditions. In East Dubuque, Illinois, bulk fertilizer storage company IEI Barge Services began looking for a bulk storage building to accommodate business growth. However, the poor soil conditions at the site would have required costly replacement.
“Because of our soil issues, we simply couldn’t afford to construct a more traditional building,” said Joe Bitter, general manager of Alliant Energy/IEI Barge Services. “The lightweight design of our building allowed us to reach a compromise between soil conditions and cost.”
Energy Use
For off-grid or energy-conscious customers, finding a way to light, heat, ventilate and otherwise power a large industrial structure can be a challenge. Fabric buildings incorporate a few key design elements that make them ideal for energy-constrained deployments. For example, Solar Ship, Inc. builds aircraft that operate on solar power. When the need arose for a new hangar in Brantford, Ontario, Canada, one of the design constraints of the building was to support the company’s commitment to solar power—the building was to operate off-grid. A steel-framed, fabric-clad building from Legacy Building Solutions was selected. The steel frame of the building is engineered to support a rooftop array of solar panels as well as 1.18 kPa (24.64 psf) rain-on-snow load.
In addition to supporting the solar panels, the building’s fabric sheathing is translucent, allowing abundant daylight into the structure, eliminating the need to turn on electric lights during daytime operation. The fabric does not conduct heat, keeping the building at a more consistent temperature as weather conditions change. Fiberglass batt insulation, linings or soffit vents are optional to help deal with cold or hot environments.
Passive Ventilation Options
Some fabric buildings, such as hoop barns, don’t have eaves, as the roof and walls are covered by a single panel. This usually limits passive ventilation to open end walls or exhaust vents near the roof. Legacy Building Solutions uses a patented panel attachment system, meaning that buildings have a combination of upright walls, eaves and soffits. Soffit vents, open walls or ridge vents allow fresh air to flow through the building naturally, allowing exhaust heat to escape at the ridge while heavier, cooler air flows in under the overhangs.
Active Ventilation Options
The steel structural members of a fabric building can support fans, louvers and exhaust vents to gain more control over airflow in the structure. Ventilation components are specified during the design phase and installed during building construction.
Dimensions and Shapes
Prefab and modular building solutions don’t address a key design need most industrial customers have: the need for custom and unique dimensions and shapes of buildings. A good example of this is the Quonset hut or hoop barn, or any structure with a semicircular wall and roof profile. It’s impossible to bring a vehicle close to the wall inside these structures, an essential requirement of many applications, such as storage of pallets or bulk materials.
In Van Buren, Arkansas, Five Rivers Distribution chose fabric buildings for this exact reason. “We like the sidewall columns going straight up instead of curving down like in our hoop buildings,” said Marty Shell, president of the company. “First off, it lets us put more product in there. And our front-end loaders can get much closer to the walls and drive straight down the sides. It gives us more working room and increases our efficiency.”
Custom dimensions and shapes are easily accommodated by steel-framed fabric buildings. For example, the Regional Water Resource Agency in Owensboro, Kentucky, needed a structure to shade existing settling tanks from direct sunlight to prevent algae growth. Legacy Building Solutions designed and constructed an open-walled pavilion over the tanks, 136 feet wide and 112 feet long. The pavilion was constructed while the water treatment system was running, causing only limited downtime. The fabric roof keeps sun off the tanks, while the open walls maintain unrestricted flow of fresh air.
Clear Span
Clear span can be a challenging design feature for some structure types, but it is essential in a space where large vehicles need to maneuver. The fabric building at Solar Ship, Inc. mentioned above measures 176 by 231 feet, for over 40,000 square feet of clear area. The building also measures 60 feet tall at the side wall and 80 feet tall at the peak. The building houses aircraft with up to 160-foot wingspans. That’s why the building also has a sliding door measuring 164 by 59 feet. The building was designed the steel frame which supports the doors as they extend beyond the sides of the building.
Legacy buildings are suitable for extreme spans because the rigid steel frame is the same type as would be used for a steel-sheathed building but is instead sheathed with PVC fabric panels under biaxial tension. The steel frame is engineered for each project for structural soundness.
Mezzanines, Catwalks and Conveyors
Thanks to the steel frame and engineering, heavy loads can be mounted inside a fabric building, such as catwalks, gantry systems or conveyors. For example, an overhead conveyor was essential for IEI Barge Services, where 27,000 tons of fertilizer are turned over three times a year.
In its 77 by 580-foot building, the conveyor load is designed for a fully loaded weight of 350 pounds per lineal foot. The building has to receive product via rail, truck and barge, and includes six concrete storage bays with bin lift gates. Each storage bin is a different size to accommodate the product, and the bins are made of pre-cast panels that can be reconfigured as needed.
Legacy buildings also accommodate reconfiguration of side walls, openings, or end walls.
Corrosion Resistance
Fabric buildings are the most flexible building choice because everything can be customized—even the walls, doors and beams. For example, in the storage of corrosive materials such as fertilizers or salts, the solid steel frame can be coated or galvanized to prevent corrosion. Solid steel is also more corrosion resistant than tubular steel. For example, a salt storage facility at the Municipality of Bethel Park in Pennsylvania had to be designed to house 4,000 tons of road salt.
The exclusive ExxoTec PVC fabric made by Legacy is resistant to common corroding agents like salts, acids and alkalis. The solid steel frame can also be set on concrete side walls to isolate them further. At Bethel Park, cast-in-place concrete walls were added. Good ventilation and rainwater management design choices, such as eave overhangs, can also help mitigate corrosion. The mandate of the Bethel Park facility was to prevent the road salt from contaminating local groundwater, so rainwater management was essential.
Fast Construction
Fabric structures don’t always get the consideration they deserve, but their flexibility and customizability make them a superior choice to pre-engineered and traditional buildings. Legacy uses a different engineering approach than other fabric buildings in the market. According to the company, it was the first to combine the steel frame of a traditional building with fabric panels held under biaxial tension. This panel system also allows the buildings to be erected faster.
Bethel Park Municipal Manager Shawn Arbaugh recalled how the fabric building construction occurred at the same time as other projects: “There was just a flurry of activity. Legacy was able to work with four other contractors to make sure people were not in each other’s way,” he said.
For more information about steel-framed fabric buildings, visit the Legacy Building Solutions website.
Legacy Building Solutions has sponsored this post. All opinions are mine. --Isaac Maw