Studying the Flexural Behavior of Reinforced Concrete Beams under the Effect of High Temperature: A Finite Element Model

摘要

The strength of concrete elements can be greatly a?ected by elevated temperature as in fres, and so a great concernmust be taken regarding its behavior under such condition. In this paper, a fnite element model was built up usingABAQUS software to investigate the ?exural behavior of reinforced concrete (RC) beams subjected to serviceload under elevated temperature. The beam was simply supported and was loaded at one-third and two-third ofspan length. The study consisted of three RC beams models; the frst model simulated a control beam specimenat ambient temperature 20 °C, while the other two models demonstrated damaged beams specimens accordingto two high temperatures 400 °C and 800 °C, respectively. Each RC beam had 2 m span length, 300 mm heightand 200 mm width. The steel reinforcement confguration was 3?16 mm (Grade 60) main bars at the positivemoment region in the beam bottom, 2?14 mm (Grade 60) secondary bars at the beam top, and ?10 mm /150 mmclosed stirrups. The model was validated by comparing its results with the theoretical results from ACI code andliterature. Several mechanical properties were investigated including concrete compressive strength, modulus ofelasticity, and reinforcing steel yielding strength. The test results showed a reduction in the ?exural capacity of theRC beams, tested at 400 °C and 800 °C, of 17.6% and 88.2%, respectively, with respect to the control beam. Themaximum service load carried by the beam, at one-third and two-third of the span length, decreased by 17.1% and88.1% for the 400 °C and 800 °C high temperature, respectively. The results also showed an increase in de?ectionwhen the temperature increased due to the loss in sti?ness.