Foundations
Work on site starts with foundations and setting out.
Before erection commences the position of the column bases, most usually laid by others, should be verified by the steel contractor. Minor discrepancies in the position of the column bases can normally be accommodated by the holding down bolt detail, and levels are usually adjusted using steel shims, inserted between the steel and the concrete, the gap being grouted once the steelwork is positioned.
Columns are fixed to foundations via a steel base plate and holding down bolts
The foot of a column is usually welded to a steel base plate, drilled to receive the holding down bolts. The bolts are cast into the concrete footing. In view of the tolerance considerations, the bolts are unlikely to fit if they are cast into the footing in advance, unless provision for considerable freedom of movement is made.
