Column splices are used to join individual lengths of columns in line.
Because of limitations on the size of components which can be transported, columns are typically delivered to site in lengths of not more than three storeys. In multi-storey construction it is therefore necessary to join individual lengths. These connections are referred to as column splices and various details can be used.
Column splices are required to transmit compressive stresses between the connected lengths.
The structural actions in a column splice involve the transmission of compression stresses from the upper length of column to the lower.
A variety of splice details are possible: welding, capping plates, and splice plates.
The connection can be achieved by welding in which case the compression forces are transmitted directly from the member above to the member below. A welded connection like this is usually used only in the fabricators shop.
An alternative is to use shop-welded capping plates to each column length. These are bolted on site to locate the plates together. A considerable advantage is that different cross-sectional sizes can be accommodated.
Splice plates are also common; they require no welding in the fabrication shop and provide some tolerance during erection. Packing plates can be used where the column cross-sections are not the same size.
The connections using capping or splice plates are more likely to be used on site because they are quicker to erect, require no weld inspection, and they are therefore cheaper. Tolerance problems between the two shafts are also avoided, as the end plates can be used as spreaders, or packing plates can be inserted under the flange plates and the web if necessary.
Aspects other than structural characteristics should also be considered.
With some care, the connection can be detailed so that it can be accommodated within the net column section, providing a flush surface and minimising the overall size of the clad column.
Splice plates are unlikely to be acceptable as an exposed joint and is not suitable for circular hollow section columns.
Welded splices are suitable for use in a truss which is fully fabricated in the shop. It is much better than splice or end plates for exposed roof trusses because there are no obstructions to trap water and cause corrosion.