Structural Factors

Before You Buy: Structural Considerations for Your Custom Fabric Structure

Every design choice can affect material requirements for strength and durability. Knowing your options is key to the success of your design and the lifespan of your building.

To construct a long-lasting fabric structure, all materials must be carefully chosen for quality and durability.

Structural Frames vs. Open Web Trusses

Legacy Building Solutions uses structural steel frames for all fabric buildings. We were the first to attach fabric cladding to a solid steel frame, rather than the open web trusses used by many fabric structure manufacturers.

The Problem with Open Web Trusses
There is controversy in the industry regarding the structural integrity of web truss designs. One type of structural failure is “chord plastification,” where a thin steel web within the truss “punches” through the wall of the supporting web frame, eventually leading to instability or structural failure.

Solid Steel Beams or Hollow Web Trusses?
The frame pieces of open web trusses are hollow and connected only by welded steel cords. Legacy uses solid steel I-beam frames. This makes a significant difference in the building’s structural integrity.

More than Strength – Other Advantages of Structural Frames

  • Design flexibility: Rigid steel frames use proven engineering principles for unlimited design options.
  • More useable space: Straight sidewalls create interior space and allow large doors in any location.

Secondary Framing Features

To further reinforce our steel frame designs, Legacy includes secondary framing practices that add to the strength and lifespan of our fabric buildings.

  • Purlins
  • Flange Braces
  • Cross Cables and Bracing Rods

Fabric and Fabric Pressure

Fabric pressure and tension play a critical role in the strength and durability of fabric covered structures.

Individual Bay Panels
Unlike the monocover fabric buildings of the past, all Legacy buildings are constructed with individual panels at the roof, walls and soffit. Roof panels, typically 20 feet wide, are attached to the frame via a keder rail. Fabric panels are double layered in any area where they contact steel.

Keder Rail Attachment: Screws vs Bolts
In most keder rail systems, the rail is secured to the trusses with TEK screws. These connections are vulnerable to corrosion and improper installation. Legacy has replaced these screws with ½-inch diameter bolts. The bolts are easier to install and last longer—especially in corrosive environments.

Endwall Design

Endwall fabric has a critical impact on the longevity, functionality and appearance of the building.

Fabric Attachment
Every endwall features our patented keder attachment system. Endwall fabric is tensioned vertically and horizontally and supported by girts. Fabric panels in the endwall are double-reinforced in all areas where they touch steel frame members.

Reinforced Structural HSS Columns
Legacy offers a column design with specially reinforced hollow structural sections (HSS). HSS endwall columns provide strength at 46 KSI while minimizing the need for lateral bracing.

Materials Used

Steel 
Our durable steel frames feature 55 KSI steel welded by our own highly skilled and certified welders. Steel frames are available hot-dip galvanized, primed or painted.

Fabric
Legacy’s premier fabric is ExxoTec™, a PVC fabric with superior strength and performance characteristics at a competitive price. ExxoTec™ is exclusively available through Legacy Building Solutions.

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