TRANSMISSION OF INTERIOR CONCRETE COLUMN LOADS THROUGH FLOORS

Clause 10, 15.3 of the 1995 ACI code (ACI 318-95) defines the effectiv e strength of a high-strength concrete interior column with an interve ning normal strength concrete slab. This provision is based on laborat ory tests in which no load was applied to the slab. Such tests may ove restimate the strength of the column because they do not properly mode l the confinement conditions of the column-slab joint. This paper repo rts experimental results of tests with properly modeled confinement co nditions. The test results show that the intensity of slab load, the a spect ratio of the joint, and the rectangularity of the column affect the strength of an interior column-slab joint. A new design equation r eplacing the provision in Clause 10.15.3 is proposed.