What is portal frame structure?
Portal frame is a construction technique where vertical supports are connected to horizontal beams or trusses via fixed joints with designed-in moment-resisting capacity. The result is wide spans and open floors. Portal frame structures can be constructed using a variety of materials and methods.
What is a portal frame rafter?
From SteelConstruction.info. Portal frames are generally low-rise structures, comprising columns and horizontal or pitched rafters, connected by moment-resisting connections.
What is the maximum span of a portal frame?
50 m
The vast majority of portal frames use hot-rolled steel sections for the column and rafter members. Using such sections, frames economically achieve spans of up to 50 m [2]. For longer span frames, an alternative to the use of hot-rolled steel sections could be fabricated steel beam sections [3], [4].
How many types of portal frames are there?
The portal frame structure has various forms: single-span, double-span, high-low-span, and multi-span, a single ridge, multiple ridge, or single slope, double slope, multiple slopes, flat slope, etc. Single-span rigid frames are mostly used in buildings with low lateral space requirements.
What foundations are used for portal frames?
Portal frames are generally fabricated from steel, reinforced precast concrete, or laminated timber sometimes referred to as ‘glulam’.
Why are portal frame structures popular?
A portal frame is a type of structural frame commonly seen in warehouses, garages, barns and sheds – anywhere a large open space is required for minimal cost. They are one of the most popular structural applications for commercial and industrial buildings because of their superior strength and structural efficiency.
What are the advantages of a portal frame?
Advantages of Portal Frames
- Quick and easy to build.
- Cost-effective.
- Can be used for multiple purposes.
- Low maintenance.
- Aesthetically pleasing.
What is a portal frame structure?
In countries where this technology is highly developed, the steel portal frame is the dominant form of structure for single-storey industrial and commercial buildings. It has become the most common structural form in pitched roof buildings, because of its economy and versatility for a wide range of spans.
What is a tied roof portal frame?
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. 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).
What is the basic composition of portal structure?
BASIC COMPOSITION • The portal structure is designed in such a way that it has no intermediate columns. • A portal frame building comprises a series of transverse frames braced longitudinally.
What are the characteristics of a steel building portal?
The roof and wall panel serves as envelope and closure of the entire structure, while also increasing the overall stiffness of the steel buildings. The span of the portal frame usually is 9～36m. When the widths of the side columns are not equal, their outer sides should be aligned. The average height of the portal frame should be 4.5～9.0mm.