Why Choose a Steel Portal Frame?
Steel portal frames are favoured for their material efficiency and space optimisation. Trusses, while also used for large spans, require more intricate fabrication, which can increase costs and construction time. Steel portal frames, on the other hand, offer a streamlined, cost-effective solution that maximises usable space within a building.
Typically, steel portal frames can span between 15 to 35 meters, but with careful design, can be made to span larger distances. A clear height (from the top of the floor to the underside of the haunch) is typically between 6 and 12m. A roof pitch of around 6° is commonly adopted
In a nutshell, steel portal frames are about creating large, open spaces with a strong, efficient steel framework. It is the go-to method for building expansive warehouses and industrial structures, thanks to its durability and flexibility.
Structural Considerations and Load Analysis
The design process for a steel portal frame begins with a thorough load analysis. At AWA we calculate the various forces the structure will need to withstand, including dead loads (the weight of the structure itself) and imposed loads (such as people walking on the roof or maintenance activities) and environmental loads such as wind and snow. These loads are combined using various load combinations to determine the overall loading on the structure.
Once the loads are calculated, we perform hand calculations to initially size the members. To optimise the design, we then use specialised software like Tekla Portal Frame Designer. This software runs calculations in accordance with Eurocode 3, the UK’s standard for steel structures, to determine the appropriate section sizes for the columns and rafters.
One of the key benefits of combining hand calculations with advanced software is the ability to accurately model the entire structure. While the load on each frame in a building is typically consistent, frames at the ends of the building experience additional wind loads. These nuances can be precisely modeled using software, ensuring that the entire structure is designed to withstand all potential forces.
Sustainability and Efficiency
The efficiency of steel portal frames – both in terms of material usage and space maximisation – makes them a sustainable option for large-span buildings. Buildings of this nature are typically built to last 50 years.
Conclusion
Steel portal frames are an efficient and versatile solution for large-span buildings in the UK. Their ability to provide wide, unobstructed spaces with minimal material usage makes them ideal for a range of applications, from warehouses to commercial buildings. By combining hand calculations with advanced software, we can ensure that these structures are both robust and compliant with UK standards.
If you are moving to a new warehouse or upgrading your existing building and require detailed drawings for your portal frame, don’t hesitate to get in touch, you can call us on 01794 524447 or email mail@awaengineers.com
Frequently Asked Questions (FAQs)
What is a steel portal frame building?
A steel portal frame building features a structure with rigidly connected steel columns and rafters, offering large, open spaces without internal supports, ideal for warehouses and industrial buildings.
What is the typical span of a steel portal frame in the UK?
Steel portal frames typically span between 15 to 35 meters.
Why do I need a steel portal frame structural engineer?
Engineers perform load assessment, structural analysis and member design to ensure the building is Eurocode compliant.