Question

Discussion topics: Why we use "Base Plate" to connect a column to foundation and what is the role of "Grout" between base plate and foundation?

Answer 1

Base plate:

Column base plates are used to connect a steel column with a R. C. C or plain concrete foundation. Cross sectional area of steel column is very much lesser than the cross sectional area of concrete because of higher strength of steel than concrete. Because of the smaller cross sectional area of steel huge load carried by the steel column will be transferred to the small portion of concrete area just below the steel cross section. As huge compressive load is transferred over a small concrete area it causes excessive compressive stress in concrete which is higher than the bearing capacity of concrete there by causing the concrete to fail.

To overcome this effect, one steel base plate of relatively larger area is provided between column and the concrete base. This plate helps to distribute concentrated load of column to a larger area of concrete thereby reducing the compressive stress acting on the concrete base below to less than the bearing capacity of concrete and hence foundation becomes safe..

Grout:

One of the important reasons of providing grout is filling the void spaces in the concrete surface in order to increase the friction between the steel plate and concrete foundation. A suitable grout provides a full contact between the base plate and footing which makes it easy to transfer the load from column to the foundation.