High Strength Concrete Columns Capacity through Lower Strength Concrete Floors

Abstract

Nine sandwich column specimens were tested to study difference in behavior of columns in presence of lower strength slab concrete in column-slab joint region. Column portions were made of higher strength concrete as compared to floor concrete. These specimens were divided in three groups, with three specimens in each group. Specimens were also designed to study the influence of aspect ratio on the behavior of column specimens. The data from these tests combined with that from the previously reported similar studies was analyzed to find the appropriate parameters for the estimation of apparent strength of the concrete to be used in the calculation of load carrying capacity of columns. Mechanics of material approach was used to evolve suitable expressions for estimating apparent concrete strength of corner, edge and interior columns. These empirical expressions can be expressed as: (for corner columns) (for edge columns) (for interior columns)

Where;