Effect of heated areas on thermal response and structural behavior of reinforced concrete walls exposed to fire

• Published in: Engineering structures Vol. 207; p. 110165
• Main Authors: Ryu, Eunmi, Kim, Heesun, Chun, Yeonju, Yeo, Inhwan, Shin, Yeongsoo
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 15-03-2020; Elsevier BV
• Subjects: Behavior; Compressive strength; Concrete; Concrete properties; Concrete strength; Eccentric loads; Experimental study; Finite element analysis; Finite element method; Fire; Fire damage; Fire exposure; Heat; Heat transfer; Heated area; Mathematical analysis; Moisture; Moisture clog; Propagation; Reinforced concrete; Reinforced concrete walls; Residual strength; Structural behavior; Temperature; Thermal response; Time compression; Walls; Concrete strength; Temperature; Heated area; Reinforced concrete walls; Fire; Moisture clog; Finite element analysis; Experimental study; Residual strength
• ISSN: 0141-0296; 1873-7323
• DOI: 10.1016/j.engstruct.2020.110165

•Thermal and structural behaviors of RC walls under and after fire are investigated.•Variables of the study are fire exposure time, compressive strength, and heated area.•There is an eccentric loading effect of fire damaged walls depending on heated area.
The purpose of this study was to investigate variations in the thermal and structural behavior of reinforced concrete (RC) walls according to the fire exposure time, compressive strength of the concrete, and the heated area. To this end, fire and axial loading tests were performed to obtain the temperature distributions and residual strengths. Heat was applied to the walls according to the ISO 834 standard time–temperature curve for 1 or 2 h. The fire test results demonstrated significant dependence of the heat propagation through the wall along the thickness on the moisture clog formed during heating. In order to show the effect of moisture clog on the heat propagation, heat transfer analyses were performed, and the results of temperature distributions obtained from the finite element (FE) model including the moisture clog zone were in good agreement with experimental results. The axial loading test results also indicated that the structural behaviors of the fire-damaged walls were affected by the fire exposure time, concrete strength, and heated area. In particular, the wall heated only on the front surface showed eccentricity, which reduced the residual strength considerably. Numerical studies for the structural behaviors of the fire damaged concrete walls were also conducted considering the eccentric loading effect due to fire. As results from the validation, the proposed simplified modeling approach was able to predict the asymmetric behaviors of fire damaged concrete walls owing to fire damage.