Structural steel frame

A steel portal frame erected off a finished slab, with the columns plumbed, the rafters seated and the purlins going on. The bays are being closed one at a time from a ladder rather than all at once, which keeps the erected part of the frame stable while the next bay is landed.

Steel is set out to the holding down bolts cast weeks earlier, so the accuracy of the frame is decided by the civil work under it. Getting the base plates and bolt groups right at foundation stage is what avoids packing and re drilling later.