Typically columns are attached at the base using holding-down (HD) bolts.  These pass through a base plate attached to the concrete by means of ‘starter bars’ welded to the top face.   The most efficient layout is for the base plate to extend beyond the face of the concrete as this gives a greater lever arm for the HD bolts.  However, this is very inefficient for precasting since the base plate will not fit within the mould.  It is usual therefore for the base plate to be flush with the column profile.

An alternative to the base plate is to use column shoes.  These are in effect ‘mini’ base plates, taking a single HD bolt, and incorporating the starter bars. Usually associated with each column shoe is the corresponding element that is cast into the foundation.  Some systems have a male insert that stands proud of the foundation.  Others have a female insert and a connecting bolt.   The advantage of the female insert in the foundation is that the surface remains flush, and free from trip hazards or projections that could become damaged by vehicles.

Column shoes are equally suitable for round, rectangular or unusual shapes (see above), and are very cost effective relative to base plates, especially where column sizes are large.