What do you need to know about portal frame buildings?

• A portal frame building comprises a series of transverse frames braced longitudinally. • The primary steelwork consists of columns and pitched rafters. • The light gauge secondary steelwork consists of side rails for walls and purlins for the roof.

What kind of steel is used in portal steel frames?

It widely used in light steel buildings such as warehouses, workshops, sheds, garages. Portal steel frame refers to the use of welded or hot rolled H-section steel as the main load-bearing framework, and cold-formed thin-wall steel (C/Z section steel or channel steel) as purlins and wall girt.

How is the span of a portal steel frame determined?

The span and column spacing of the portal steel frame mainly determined according to the building requirements. The main issues to consider in the architectural design are the determination of the temperature interval and the layout of the bracing system.

Which is the primary force skeleton of the portal steel frame?

Steel columns, roof beams, and bracing systems constitute the primary force skeleton of the portal steel frame. It is the primary framing. Roof purlins and wall girt not only support the roof and walls but also provide lateral support for the main structural beams and columns, which form the secondary framing of portal steel frame buildings.

What kind of structure is a portal steel frame?

Because of its lightweight and comfortable construction, it widely used in Workshop, Warehouse, Stadiums, and High-rise buildings. The portal steel frame is a traditional structural system. The mainframe includes Steel Column and Roof Beam, and the secondary structure includes Bracing, Strut, Purlins, and tie rods.

Why are portal frames used in the UK?

They were originally used because of their structural efficiency, meaning that large spaces could be enclosed with little use of materials and for a low cost. Tata Steel suggest that today, 50% of constructional steel used in the UK is in portal frame construction. (Ref. SteelConstruction.info, Portal Frames .)

How is the eaves Haunch used in a portal frame?

The haunch also adds stiffness to the frame, reducing deflections, and facilitates an efficient bolted moment connection . The eaves haunch is typically cut from the same size rolled section as the rafter, or one slightly larger, and is welded to the underside of the rafter. The length of the eaves haunch is generally 10% of the frame span.

Which is the most common portal structure system?

Portal Steel Frame Buildings is the most common structure system. It widely used in light steel buildings such as warehouses, workshops, sheds, garages.