Hollow Section Pillars

Hollow-section columns are structural elements widely used in civil engineering and architecture, characterized by a hollow internal geometry. This study addresses the circumstances of use, advantages, disadvantages, design aspects, materials, practical examples and maintenance considerations, based on technical standards and academic references.

 

Circumstances of Use

Hollow section columns are preferred in specific situations where their geometric and mechanical characteristics offer significant advantages:

1. Structures Subject to Dynamic Loads :
• On bridges, viaducts or tall buildings, where resistance to bending and torsion forces is critical;
• The hollow section provides greater torsional rigidity and resistance to lateral loads such as wind or earthquakes.

 

2. Weight and Material Optimization :
• In structures where self-weight is a limiting factor, such as large-span roofs or prefabricated structures;
• Weight reduction allows savings on foundations and transportation.

 

3. Service Integration :
• The internal space can be used for the passage of electrical cables, water pipes, gas or air conditioning systems, especially in commercial or industrial buildings.

 

4. Aesthetic and Architectural Requirements :
• The hollow section allows for lighter, more modern designs and is often used in exposed structures such as pavilions or urban sculptures.

 

5. Corrosive or High Temperature Environments :
• The hollow section can be filled with corrosion or fire resistant materials, increasing the durability of the structure.

Advantages of Hollow Section Pillars

1. Structural Efficiency :
• The distribution of material on the periphery of the section increases the moment of inertia, improving resistance to bending and torsion;
• The strength/weight ratio is superior compared to solid sections.

 

2. Self-Weight Reduction :
• Lower weight means lower loads on the foundations and lower transportation and assembly costs.

 

3. Application Versatility :
• They can be manufactured in different materials (steel, concrete, composites) and shapes (circular, rectangular, square).

 

4. Service Integration :
• The internal space can be used for electrical, hydraulic or air conditioning installations, reducing the need for external ducts.

 

5. Resistance to Dynamic Efforts :
• Hollow section is particularly effective in structures subject to variable loads, such as bridges or tall buildings.

Disadvantages and Limitations

1. Manufacturing Complexity :
• The production of hollow sections, especially in unconventional shapes, can be more complex and expensive.

 

2. Risk of Water Accumulation :
• In outdoor environments, the hollow section can collect water, leading to corrosion or freezing problems.

 

3. Difficulty of Inspection and Maintenance :
• The internal space may be difficult to access, complicating inspection and repair of any damage.

 

4. High Initial Costs :
• The manufacture and assembly of hollow columns may have higher initial costs than solid sections.

 

5. Behavior in Case of Collapse :
• In extreme overload situations, the hollow section may experience catastrophic failure due to local wall instability.

Materials Used

1. Steel :
• Steel hollow sections are widely used due to their high strength and ease of fabrication;
• Example: Circular or rectangular tubular profiles.

 

2. Reinforced Concrete :
• Hollow section reinforced concrete columns are used in large structures such as bridges or tall buildings;
• Concrete can be precast or cast on site.

 

3. Composites :
• Composite materials, such as carbon fiber or fiberglass, offer high strength and lightness, and are used in special applications.

Practical Examples

1. Eiffel Tower (Paris, France) :
• It uses hollow sections in wrought iron, combining lightness and resistance.

(https://www.paristickets.com/pt/eiffel-tower/architecture/ )

2. Vasco da Gama Bridge (Lisbon, Portugal) :
• Hollow reinforced concrete columns withstand extreme dynamic and environmental loads.

( https://www.lusoponte.pt/vasco-da-gama/projecto/principais-caracteristicas )

3. Beijing Olympic Stadium (China) :
• The structure uses hollow steel sections to create a lightweight and aesthetically striking roof.

( https://pt.wikiarquitectura.com/constru%C3%A7%C3%A3o/Estadio-olimpico-de-Pequim/ )

Maintenance and Durability

1. Corrosion Protection :
• In steel structures, the application of protective coatings or the use of stainless steel is essential;
• In concrete structures, the use of high-strength concrete and protected reinforcement is recommended.

 

2. Drainage of Internal Space :
• In outdoor environments, the hollow section must be equipped with drainage systems to prevent water accumulation.

 

3. Regular Inspection :
• Periodic inspection of the internal space and section wall is crucial to ensure the integrity of the structure.

Conclusion

Hollow section columns are an efficient and versatile structural solution, suitable for a variety of applications. Their use must be carefully planned, considering the advantages and disadvantages, as well as the specificities of the project. Optimizing the dimensioning, the appropriate choice of materials and regular maintenance are critical factors for the success of this solution.

Sources and Bibliographic References

UniAsen . Hollow sections: characteristics and applications . Available at: https://uniasen.com/pt/produtos/secoes-ocas/ . Accessed on: January 30, 2025.

SkyCiv . (2019). Benefits of different steel sections . Available at: https://skyciv.com/pt/technical/benefits-of-different-steel-sections/ . Accessed on: January 30, 2025.

Other Bibliography Consulted

Carvalho, AL (2013). Modelling of hollow reinforced and prestressed concrete columns [Master’s Dissertation, University of Porto]. Open Repository of the University of Porto. Available at: https://repositorio-aberto.up.pt/bitstream/10216/67435/2/64831.pdf

Gomes, RF (2016). Study of beam-column connections using rectangular or hollow square profiles [Master's Dissertation, University of Coimbra]. Estudo Geral - University of Coimbra. Available at: https://estudogeral.uc.pt/bitstream/10316/38460/1/Estudo%20de%20ligacoes%20viga%20pilar%20usando%20perfisretangulares%20ou%20quadrados%20ocos.pdf

ResearchGate . (2003). Behavior of hollow-section reinforced concrete beams subjected to bending, shear and torsion . Available at: https://www.researchgate.net/publication/242301936_Comportamento_de_vigas_de_betao_armado_de_seccao_oca_submetidas_a_flexao_corte_e_torcao . Accessed on: February 3, 2025

Author: Eng. Francisco Quisele Jr.

Date of publication : 02/05/25