While most architectural terms are cut-and-dried, “long span” is more subjective. And the definition is more or less what you expect it to be – a building or other structure that spans a long area. By general consensus, long span structures are at least 20 meters (about 65 feet).
The advantage of long span buildings is that there is more space inside. Long span buildings are popular for sports arenas and other applications requiring maximum visibility, and for bulk storage and retail uses requiring large clear area.
Professional Design and Installation
Due to the nature of long span construction, the construction materials including framing members and trusses are oversized and 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.
A licensed engineer should also be consulted in the planning stages of a long span structure. The engineer will ensure 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 and rain over long distances without excessive deflection.
For many long span structures, especially those used for sports stadiums and other high-profile applications, the appearance 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.
- 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. Many long span structures, such as the Munich Olympic Stadium, use fabric to create eye-catching shapes not available with other materials.
- Glass curtain walls on non-load-bearing walls provide a unique appearance and unite the inside and outside of the building.
Long span structure construction is a lengthy process. Before embarking on a long span construction process, be sure that you are using the right materials and the right installation team.