Column bases are structural elements used in the design of steel structures to transfer the column load to the footings.
Types of Column bases
- Slab base
- Gusseted base
Slab bases are used where the columns have independent concrete pedestals. A thick steel base plate and two cleat angles connecting the flanges of the column to the base plate. In addition to these, web cleats are provided to connect the web of the column to the base plate. These web cleats guard against the possible dislocation of the column during erection. The ends of the column and also the base plate should be mechanized so that the column load is wholly transferred to the base plate.
Area of base plate= (load of column)/(permissible bearing stress in concrete)
Gussetted bases are provided for columns carrying heavier loads requiring large base plates. A gusseted base consists of a base of reduced thickness and two gusseted plates are attached one to each flange of the column.
The gusseted plates, cleat angles and fastenings (bolts, rivets) in combination with bearing area of shaft shall be sufficient to take all loads.