Portal Frame Roof Structure

Portal frames were world war ii s answer to the need for efficient low cost construction.

Portal frame roof structure. Mono pitch portal frame it is a simple variation of the pitched roof portal frame and tends to be used for smaller buildings up to 15 m span. Steel portal frames usually have pinned bases and moment connections at the column rafter interface and mid span apex splice in the rafter. As such this type of structure is used for depots warehouses and out of town shopping. These include steel reinforced concrete and laminated timber such as glulam the connections between the columns and the rafters.

Portal frame structures can be constructed using a variety of materials and methods. Their most widespread applications lie in warehouses barns and other large single story industrial structures. Tied portal frame in a tied portal frame the horizontal movement of the eaves and the bending moments in the columns and rafters are reduced. Steel portal frame structures provide an efficient and cost effective means of creating large column free spaces.

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. Portal frame structures are designed to span between supports and rely on fixed joints with moment resisting capacity where vertical supports connect to horizontal beams or trusses. Steel columns roof beams and bracing systems constitute the primary force skeleton of the portal steel frame.