FLEXURE AND SHEAR BEHAVIOR OF CONCRETE BEAMS DURING FIRES

This paper describes the results of a research program to study the behavior of reinforced concrete beams exposed to severe fires. Data are presented from fire tests of six full-scale beams continuous over one support that were fabricated using normal-weight concrete. Four beams were exposed to the standard ASTM E119 fire, and two to a short-duration high-intensity (SDHI) fire developed using realistic fire-load and compartment-ventilation parameters. All six beams developed significant shear cracks near the continuous support rather early in the fire, but eventually failed from excessive flexural cracking and deformation. Mathematical models for predicting thermal and structural response of concrete beams exposed to natural fires, as well as the ASTM standard exposure, were also developed. These models predicted the experimental behavior with sufficient accuracy for purposes of limit-states design.