end wall section of a steel portal frame (tute 3)

As far as steel framing goes, the portal frame is the most common. The load is shared across the frame but isn't absorbed into the structure, instead all loads are transferred to the footing.

One of the great advantages of portal framing is that it can span long distances, (15-45m), therefore a building can have large open spaces without the interference of columns.

At times of great development it is somewhat surprising that portal frame sizes are governed by the size of the truck transporting them. If the frames are too large then consideration would have to be given to special transporting or additional field splices. Problems come with using field splices though because these joints weaken the overall beam. To counter this they are usually placed as close as possible to a dead load.