A SIMPLIFIED METHOD FOR ESTIMATING LOAD CAPACITY
OF THREE-SIDE FIRE-DAMAGED COLUMNS/BEAMS
34th Our World in Concrete and Structures (OWICs) - 2009
L X Liu*, Florida Atlantic University, Boca Raton, FL, U.S.A.
D V Reddy, Florida Atlantic University, Boca Raton, FL, U.S.A.
K Sobhan, Florida Atlantic University, Boca Raton, FL, U.S.A.
Simplified method, RC column, high temperature exposure, cross-section
enlargement, interactive diagram, load capacity
A simplified method is proposed to calculate the load capacity of RC columns and
beams fire-damaged on three sides, taking into consideration the cross-section size,
the load eccentricity, and the non-uniform and asymmetrical temperature distribution
during fire exposure. The simplification is in two aspects: (i) the cross-section is
replaced by an equivalent cross section, and (ii) the curved interactive axial forcemoment (N-M) diagram is approximated by a piecewise straight line relationship.
The accuracy of the method is verified with three sets of experimental test results of
21 columns. The method yields reasonably accurate predictions for the load capacity
of RC columns fire-damaged on three sides, during or after fire exposure. In addition,
the paper includes one worked example to illustrate the use of this method for
predicting the load capacity of an eccentrically loaded RC column heated on three
sides. The results are compared with the experimental results, and the good
agreement indicates that the adequacy of the simplified method for design.