Seismic Resistance of Fire-Damaged Reinforced Concrete Columns

A study was carried out on the assessment of the residual strength and lateral/seismic load capacity of reinforced concrete columns after fire exposure. The mechanical properties of concrete after fire exposure, such as residual tension and compression strength, stiffness and constitutive responses, were reviewed. A nonlinear finite element analysis program, developed for three-dimensional reinforced concrete structures, was employed to estimate the post-fire axial and lateral performance of two full-scale reinforced concrete columns, tested previously at the National Research Council Canada. The results of the axial load-deformation response obtained from the analysis were compared and verified successfully with the test data. The lateral load and deformation responses of the specimens were then estimated using the numerical program. The results showed that both the lateral/seismic load capacity and ductility of the two reinforced concrete column specimens decreased noticeably due to the fire exposure. Studies are suggested on fire damage mitigation and post-fire shear strength recovery of reinforced concrete columns.