Effect of burning by fire flame on the behavior of reinforced concrete beam models

الملخص EN

This research is devoted to investigate the behavior of reinforced concrete beams loaded and exposed to fire flame.

In this study, some mechanical properties and deflection behavior of rectangular reinforced concrete beam specimens under the effect of burning is presented.

The concrete specimens and beams were subjected to fire flame temperatures ranging from (25-800 °C) at different ages of 28, 60 and 90 days, three temperature levels of 400, 600 and 800 °C where chosen for exposure duration of 1.0 and 2.0 hours.

Load-deflection curves indicate changing response with the fire exposure.

Also, it was found that the shrinkage values increase with temperature increase.

Results indicate remarkable reduction in flexural strength after exposure to fire flame.

The residual flexural strength is (88 and 81 %) with 1.0 and 2.0 hour exposure periods respectively at fire temperature (400 ºC), while the residual at fire temperature (600ºC) is (66 and 53 %) with 1.0 and 2.0 hour exposure periods respectively, while the residual at fire temperature (800 º C) is (45 and 36 %) with 1.0 and 2.0 hour exposure periods respectively.

It is found that the ACI 318 / 2008-Code equations are safe to predict bending moment capacity for fire temperature (400 º C), while at burning (600 º C) gave overestimated results to predict moment capacity, but become unable to predict moment capacity at fire temperature (800 º C).