One of the symbols of Paris and France as a whole, as well as one of the most famous buildings in the modern world, the Eiffel Tower’s construction officially began in 1887 and was completed in 1889. The steel structure of the tower consists of approximately 18,000 components, weighing more than 7,000 tons, with over 5,300 design drawings produced. At the time of the building’s completion, the Eiffel Tower stood at about 300 meters, making it the tallest truss structure in the world until 1930. The creation of the Eiffel Tower likewise accomplished a great journey from the age of wood and stone construction to the modern age of reinforced concrete.
This article will help you learn in detail what a truss structure is. As well as the characteristics and typical truss structure of buildings.
Introduction of truss structure:
A truss structure is a framework composed of members connected at their ends by pin joints. All members lie within the same plane and primarily bear axial tension or compression forces, efficiently transferring loads through the structure. Typically, these members are arranged in triangular units, as the inherent stability of triangles ensures the overall rigidity of the structure. However, other geometric configurations can also be used.
Classification of truss structures:
- Space truss structure: mainly used in the construction of large-span space buildings. It can link the trusses together to maintain the complete three-dimensional grid system stress, which makes its space system stronger, has a larger span, and can share the load more reasonably. It is usually used in large-span structural buildings.
- Special-shaped space truss structure: This is a special building structure that mostly appears in construction projects that require large spans and non-traditional shapes. They also often appear in architectural design, creating unique architectural forms and aesthetic effects.
- Special-shaped space tube truss structure: It has high flexibility and adaptability and can meet the needs of various complex building structure spaces. The special-shaped space tube truss structure has more impact and architectural beauty in terms of architectural vision. It can be applied to large-span buildings, realize a large-space column-free design, and enhance the artistic value of the overall building.
Features of the truss structure:
- A space truss is capable of bearing loads from multiple directions. Unlike a planar truss, which only functions effectively within its own plane, a space truss efficiently distributes and transfers both vertical and horizontal loads through its members. The mutual constraints between members create a stable spatial system. For example, when subjected to uneven loading, a planar truss may experience torsional buckling, whereas a space truss resists such deformation due to the restraining effect of its three-dimensional grid members. Additionally, space trusses are typically statically indeterminate structures, meaning they can retain some load-bearing capacity even if certain members fail or sustain localized damage.
- Special-shaped space truss structure: These are less regular than traditional ones. They are designed in geometric shapes to meet specific architectural functions and modeling requirements. For example, the roofs of some buildings look wavy, and the sizes and shapes of the peaks and troughs are different. This irregular shape is achieved through the asymmetric arrangement of rods and special node connections. Special-shaped space trusses can form complex spatial curves and surfaces, guide the flow of rainwater, bend in multiple directions in three-dimensional space, and create shapes such as hyperbolic paraboloids and free-form surfaces to give the building a more dynamic appearance. At the same time, the truss structure can be differentiated according to the internal functions required, and the undulating spaces formed in different areas can also provide the audience with a diverse spatial experience.
Due to the irregular shape of the special-shaped space truss, its stress condition is much more complicated than that of the regular space truss. The complex shape of the special-shaped space truss will also affect its ability to bear horizontal loads.
- Special-shaped space tube truss structure: The special-shaped space tube truss structure is not restricted by conventional geometry and can allow for free twisting and large-angle buildings. This structure is not as monotonous as ordinary planes or simple curved surfaces. The free-form surface can shape the space with smooth lines and variable structural designs and has good spatial adaptability, better adapting to various complex architectural space requirements and creating rich and varied spatial experiences.
Due to the irregular shape of this special-shaped space tube truss structure, the force is relatively complex, and the load transfer is not linear like ordinary structures. However, the full utilization of materials can be considered at the beginning of the design, and the materials can play the maximum role in tension and compression through precise calculation. At the same time, the pipe is the most critical part of the specially-shaped space tube truss. The same material can have higher strength and rigidity than solid rods. If the aesthetic requirements for the building are high, it is necessary to match the node’s appearance with the entire structure of the special shape, and the overall visual effect cannot be destroyed. For example, in a tube truss building with a unique shape, the knot can be hidden or decorated next to it to integrate with the pipe fittings.
*The Yangcheng Lake Hairy Crab Museum is located in Suzhou City, Jiangsu Province. It was built by Suzhou Wujiang XTD Steel Structure Engineering Co., Ltd., with a construction area of approximately 4,630 square meters, and is an irregular space structure.
*The East Zhejiang Canal Museum is located in Shaoxing and was built by Suzhou Wujiang XTD Steel Structure Engineering Co., Ltd. It is an irregular space structure with an approximately 34,000 square meter construction area.
Truss structure architectural example:
Machinery Pavilion at the Paris Exposition of 1867
*The Paris World Expo Machinery Pavilion was designed by engineers J.B. Krantz and Eiffel and completed in 1867. It used three steel-hinged arches with a truss structure in a cross-section. There were 20 such steel arches, 115 meters wide and 420 meters long, and the interior space was extremely large.
Sydney Opera House, 1973
*The Sydney Opera House was built in 1973 by architect Jørn Utzon. It has a unique shape consisting of three large shells, which are made of prefabricated concrete components and steel truss structures. It is located in Sydney, Australia, and is one of the most representative buildings of the 20th century.
*The San Francisco International Airport terminal building was designed by Skidmore, Owings & Merrill (SOM) and other collaborative teams. The design was completed in 1995 and completed in 2000. The skylight was made using the spatial truss structure.