Long-Span Structures: Critical Factors for a Successful Project

    Ontario International Airport Legacy Project
    January 10, 2022 | Tension Fabric Structures, ExxoTec, Building Design

    By definition, everything Legacy builds is a long-span structure. Long span is defined by the width of the building, the span of the roof frame across the entire structure. Anything more than 20 meters is considered long span, but for Legacy that’s on the low side. These wide open structures are also known as clear span or free span buildings.

    A key component of our long-span buildings is that there aren’t central column supports, and that gives our customers unobstructed floor space.

    Long-span buildings are for people (or organizations or horses) who need a lot of space. Good examples include sports facilities, warehouses, hangars, equestrian arenas and bulk storage.

    Professional Design and Installation

    Due to the nature of long-span construction, the framing members and trusses require special care for installation. Long-Span structures may need bracing during craning and construction to keep the materials true. Before constructing a long-span structure, make sure the contractor and building installation crews have experience working with buildings of similar size.

    Legacy, for example, uses our own crews for most installations, so their training and experience make them experts in long-span buildings.

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    A licensed engineer should also be consulted in the planning and design stages of a long-span structure. The engineer will make sure that the building is structurally sound and meets local building codes. Because the roof of the structure is not supported with interior columns, the structure must be designed to withstand snow, wind, rain and seismic movement without excessive deflection.

    For sports facilities, the appearance of a long-span structure inside is as important as the functionality of the structure. In these cases, an architect is typically part of the team designing the building.

    Materials Used in Long-Span Building Construction

    Certain construction materials are better suited for long-span structures. Long-span structures must be made of materials light enough to not require interior supports, yet sturdy enough to withstand the pressures placed on the structure.

    • Steel is a common building material for long-span structures. Steel is strong and relatively lightweight, so it is suitable for the building frame and/or the outside cladding. Legacy was an innovator when it shifted to solid steel frames a few years back. It allows us to create long-span spaces up to 300 feet wide.
    • Wood, particularly wooden trusses, may be used for smaller long-span buildings. Long wooden beams are more expensive and harder to locate, so wood is less common for larger buildings.
    • Structural fabric is a common choice for long-span structures because fabric structures are lightweight, inexpensive and can quickly cover large surfaces. Legacy uses a PVC-based fabric called Exxotec™ that is unique to our buildings. It’s tough, it’s beautiful and it has a 25-year pro-rated warranty (for the 28 oz. fabric).

    In addition to strong frames and tough exterior cladding, Legacy fully customizes every building we install. There are no off-the-shelf buildings because we believe every customer has unique requirements. Our design team isn’t interested in shoe-horning you into a building that only partially meets your needs. Contact Legacy if you want the whole package: a long-span building that is state-of-the-art in terms of engineering and functionality.





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