Title:
Behavior of Columns Continuous Through Concrete Floors
Author(s):
C.C. Shu and N. M. Hawkins
Publication:
Structural Journal
Volume:
89
Issue:
4
Appears on pages(s):
405-414
Keywords:
columns (supports); concrete slabs; high-strength concrete; connections; reinforced concrete; structural design; Structural Research
DOI:
10.14359/3023
Date:
7/1/1992
Abstract:
Concerns the behavior of high-strength concrete columns intended to be continuous through lower strength concrete floors. Tests were made on 54 sandwich column specimens, consisting of high-strength concrete ends framing a lower strength, variable depth, concrete central section. Restraint from the higher strength upper and lower parts of the column increased the capacity of the lower strength central portion of the column. The magnitude of that effect varied with the ratio of the depth of the central part to the column's side dimension and the ratio of the concrete strength for the upper and central parts of the column. Based on the results of this investigation, a formula was developed for the effective concrete strength of a sandwich column. From that formula a simplified expression was developed suitable for incorporation into code provisions such as ACI 318. That formula can be said to provide a lower bound to the effective concrete strength for edge and corner columns where there are low-strength concrete slabs and/or beams continuous through a higher strength column.