Title: Effect of Sustained Service Loading on Post-Fire Flexural Response of Reinforced Concrete T-Beams

Author(s): Chanachai Thongchom, Akhrawat Lenwari, and Riyad S. Aboutaha

Publication: Structural Journal

Volume: 116

Issue: 3

Appears on pages(s): 243-254

Keywords: elevated temperatures; finite element analysis; fire damage; flexural response; reinforced concrete beams; sustained service loading; thermal response

DOI: 10.14359/51714477

Date: 5/1/2019

Abstract:
This paper presents the effect of sustained service loading at elevated temperatures on the residual flexural response of reinforced concrete (RC) T-beams after exposed to elevated temperatures of 700 and 900°C (1292 and 1652°F) for 3 hours and then cooled in air. Two beams were subjected to a constant simulated service loading equal to 22.6% of undamaged (unheated) flexural strength, while the counterpart beams were exposed to fire without any applied sustained load. The test results showed that the bottom (tension) steel reinforcements in all fire-exposed beams had experienced the peak temperatures that were higher than a critical value (593°C [1099°F]) before the post-fire static test. The post-fire static test results showed that the sustained loading has a detrimental effect on the post-fire flexural response of RC beams. The effect was more pronounced on the post-fire stiffness and ductility than on strength. In the paper, simplified finite element models for predicting the temperature response and post-fire load-deflection relationships of fire-exposed RC beams are also described.