What Is a Long-Span Structure? Here It Is

Have you ever walked into a stadium, exhibition hall, or airport and wondered how they managed to create such vast, open spaces with no internal columns? How do they accommodate thousands of people while maintaining flexibility? What makes these spaces so functional yet visually striking? Long-span structures make it all possible, but how do they work, and what are the real benefits and challenges? Let’s dive in and explore how these engineering wonders shape the spaces we interact with every day.

In this guide, you’ll learn about:

• What long-span structures are
• Their benefits and challenges
• Real-world examples
• Structural types and materials used in long-span designs
• Differences between long-span and short-span structures
• The differences between long-span, short-span, and large-span structures

Let’s not waste time and dive right in!

What Are Long-Span Structures?

Long-span structures are buildings or frameworks with an uninterrupted space of over 30 meters (100 feet). They don’t have internal columns or supports, creating a wide, open area. These structures are often used where large, column-free spaces are needed, such as in airports, sports arenas, exhibition halls, or aircraft hangars.

Pros & Cons of Long-Span Structures

Pros of Long-Span Structures

• No internal columns create large, open spaces, making the area flexible for various uses like sports events, exhibitions, or warehouses.
• Materials like steel and concrete are strong and durable, meaning the building lasts longer with less need for maintenance.
• Clear sightlines in arenas, auditoriums, and event spaces provide better views for large audiences.
• The large, open design makes these buildings stand out and often turns them into landmarks.
• Fewer supports allow the space to be easily adapted for new uses, such as converting a sports venue into a concert hall.

Cons of Long-Span Structures

• Special materials and complex designs can increase the cost of construction.
• Building large spans requires advanced engineering, which can extend the design and construction time.
• Large roofs and lightweight designs can be more vulnerable to extreme weather, requiring extra protection against high winds or earthquakes.
• Steel and other materials need regular inspection and care to prevent issues like rust or wear.
• Only a few materials like steel and reinforced concrete can support long spans, which limits material options.

Applications of Long-Span Structures

Long-span structures are used in a variety of building types, and their applications are diverse. Some common uses include:

• Sports Stadiums: These require wide open spaces for spectators, without any columns obstructing views.
• Exhibition Halls: In exhibition spaces, flexibility and large floor areas are key to showcasing large items or accommodating large crowds.
• Airports and Hangars: Aircraft hangars, in particular, need large spaces to house planes, making long-span structures ideal.
• Industrial Buildings: Some factories or warehouses use long-span designs to allow for large machinery or bulk storage needs without interfering with workflow.

5 Iconic Long-Span Structure Examples Worldwide

Here are five iconic long-span structures that have set new standards in architecture and engineering:

1. Sydney Opera House, Sydney 

The Sydney Opera House is a prime example of long-span architecture, famous for its unique roof design. The roof features precast concrete shell segments, each spanning over 15 meters. These reinforced concrete segments were a groundbreaking innovation when built (1957-1973), allowing the structure to have a large, open interior without the need for support columns.

The roof’s large spans provided expansive performance spaces beneath, offering both unobstructed views and excellent acoustics. The Sydney Opera House continues to be a masterpiece of long-span engineering, showing how shell structures can create spacious, column-free areas with stunning visual appeal.

2. Beijing National Stadium (Bird’s Nest), Beijing 

The Beijing National Stadium, or “Bird’s Nest,” is a modern example of long-span steel design. Built for the 2008 Summer Olympics, the stadium features a steel frame that spans over 80 meters at its widest point, with no internal supports blocking the seating area. The interwoven steel beams create a “nest” that holds up the roof, covering a space of over 330 meters without relying on load-bearing walls or columns.

This long-span design allows for large crowds to gather in a single uninterrupted space, a crucial feature for stadiums. The Bird’s Nest demonstrates how modern steel construction can create bold, expansive structures that are both functional and visually stunning.

3. The O2 Arena, London 

The O2 Arena is known for its iconic long-span roof, which stretches over 100 meters. The roof is made from steel and tensioned membrane fabric, supported by a series of masts and cables. This design allows the structure to be lightweight and efficient while covering a vast area without internal columns, maximizing usable space inside.

The O2 Arena’s roof design is key to its function as a multi-purpose venue, providing unobstructed views for concerts, sports events, and other large gatherings. It showcases how steel and tensioned fabric can work together to create a flexible and visually striking long-span structure.

4. Heinz Field, Pittsburgh 

Heinz Field in Pittsburgh is a notable example of long-span steel truss engineering in sports stadiums. The stadium features a cantilevered roof system supported by steel trusses, spanning approximately 50 meters across the seating areas. This design eliminates the need for internal columns, offering fans an unobstructed view of the field.

The steel trusses used in Heinz Field’s roof are a common solution for long-span stadiums, providing strength, efficiency, and the ability to withstand heavy loads like wind and snow. The design balances structural integrity with functionality, making it ideal for large public venues.

5. Dallas/Fort Worth International Airport (DFW), Dallas, Texas 

Dallas/Fort Worth International Airport is a great example of long-span roof design in transportation infrastructure. The airport’s roofs span up to 60 meters across multiple terminals, creating spacious, open areas that improve passenger flow and the overall experience. The roofs combine steel supports (trusses and beams) with concrete slabs, creating wide, column-free terminal spaces.

This design not only increases efficiency but also enhances the airport’s aesthetic appeal, offering clear sightlines and a sense of openness in a busy, large-scale environment. DFW Airport shows how long-span structures can optimize functionality and user experience in complex public facilities.

Structural Types of Long-Span Structures

When designing long-span structures, it’s crucial to choose systems that can support large distances while staying strong, stable, and efficient. These structures are usually divided into two categories: bending structures and funicular structures. Each has its strengths and is suited for different types of projects.

1. Bending Structures

Bending structures handle both pulling (tension) and pushing (compression) forces. These are often used in large buildings and bridges where the structure needs to support heavy loads over long distances.

• Trusses: A common bending structure made up of triangular units. They’re great for large spans, often seen in roofs and bridges. Steel trusses can span up to 190 meters (623 feet), making them ideal for stadiums or large exhibition halls.
• Plate Girders: These are deep beams made by welding steel plates. They can span up to 60 meters (200 feet) and are used in bridges or large roofs. However, they aren’t as material-efficient as trusses.
• Two-Way Grids: These distribute loads in both directions across a surface, forming a grid. They’re great for covering large areas, like airports or exhibition halls, and can span up to 91 meters (300 feet).
• Space Trusses: These are 3D trusses that handle very large spans (up to 190 meters/623 feet). They’re often used in large roofs or long-span bridges.

2. Funicular Structures

Funicular structures only handle either tension (pulling) or compression (pushing) forces, making them efficient for very large spans with minimal material.

• Parabolic Arches: These arches distribute compressive forces evenly, making them ideal for long-span bridges and roofs. They often combine with steel or concrete for added strength.
• Dome Structures: Domes are compression-based structures, efficient for creating large open spaces. The largest steel domes can span over 200 meters (669 feet), often used in stadiums and public buildings.
• Tension Cable Systems: These use steel cables stretched across a span. They’re lightweight and can support large distances (up to 72 meters/236 feet). Tension-cable systems are common in sports stadiums and exhibition halls.
• Bicycle Wheel Roofs: A tension-based design where cables form a wheel-like pattern. They’re lightweight and strong, often used in temporary structures or places that need easy construction.
• Tension-Membrane Systems: These use fabric stretched over cables, creating a flexible, lightweight structure. They’re often used for sports arenas or pavilions.

3. Hybrid Systems

Some modern long-span structures combine both bending and funicular elements to achieve the best performance and look.

• Composite Roofs: These combine steel trusses with tensioned cables or fabric membranes to create lightweight, strong roofs. They are great for column-free spaces.
• Steel and Concrete Combinations: In some buildings, concrete is used for compression elements (like arches), while steel handles tension (like cables or trusses). This mix improves strength and cuts costs.

Materials for Long-Span Structures

Choosing the right material is key to making a long-span structure strong and efficient. Here are some materials commonly used:

• Steel: Steel is often the material of choice for long spans due to its high strength-to-weight ratio. Steel trusses, plate girders, and cable systems are commonly used in long-span structures, with steel able to span up to 190 meters (623 feet) in some cases.
• Timber: Glulam (glue-laminated timber) is used in some long-span structures, especially in areas with access to forests. It’s often used for trusses and compression forms, with spans of up to 45 meters (150 feet) for trusses and 93 meters (305 feet) for domes.
• Concrete: Concrete is ideal for compression-based funicular structures, like arches and domes. It’s less common in bending structures but excels in supporting large spans with less material.
• Fabric and Membrane: Tensioned fabric structures, like those used in sports arenas, rely on lightweight materials supported by cables. These can span large areas with minimal cost and material.
• Composite: Sometimes, designers combine materials like reinforced concrete with steel or timber with metal connectors to get the best of both worlds—strength, flexibility, and lower costs.

Long-Span vs. Short-Span Structures

The main difference between a long-span and short-span structure is the length of the span and the complexity of their design.

Long Span Structures

• Span over 30 meters (100 feet) or more without internal columns.
• Designed to create large, open spaces.
• Requires advanced engineering, specialized materials, and often higher construction costs.
• Commonly used for sports stadiums, exhibition halls, and aircraft hangars.

Short Span Structures

• Span under 30 meters (100 feet).
• Can rely on simpler engineering solutions and may use internal columns or supports.
• More cost-effective and easier to construct.
• Suitable for smaller buildings, warehouses, and office spaces.

In summary, the key difference is the span length. Long-span structures need more complex engineering and materials to create larger, unobstructed spaces.

Long-Span vs. Large-Span Structures

Though “long span” and “large span” are often used interchangeably, they refer to different aspects of structural design:

Long Span

• Refers to structures that span over 30 meters (100 feet) without internal supports or columns.
• Focuses on the distance of the span and the engineering required to create large, uninterrupted spaces.
• Common in buildings like sports arenas and exhibition halls.

Large Span

• Refers to structures with spans over 100 meters (328 feet) or more.
• Emphasizes the overall size and scale of the space, often for massive industrial or recreational purposes.
• Examples include large airport terminals or major exhibition halls.

“Long span” is about the distance the structure covers, while “large span” is more about the overall scale and width of the structure. All large-span structures are long-span, but not all long-span structures are large-span.

Conclusion

That’s it: Long-Span Structures.