Effect of Wall Thickness on Thermal Behaviors of RC Walls Under Fire Conditions

Abstract

The objective of this paper is to investigate the effect of thickness and moisture on temperature distributions of reinforced concrete walls under fire conditions. Toward this goal, the first three wall specimens having different thicknesses are heated for 2 h according to ISO standard heating curve and the temperature distribution through the wall thickness is measured. Since the thermal behavior of the tested walls is influenced by thickness, as well as moisture content, three additional walls are prepared and preheated to reduce moisture content and then tested under fire exposure. The experimental results clearly show the temperatures measured close to the fire exposed surface of the thickest wall with 250 mm thickness is the highest in the temperatures measured at the same location of the thinner wall with 150 mm thickness because of the moisture clog that is formed inside the wall with 250 mm of thickness. This prevents heat being transferred to the opposite side of the heated surface. This is also confirmed by the thermal behavior of the preheated walls, showing that the temperature is well distributed in the preheated walls as compared to that in non-preheated walls. Finite element models including moisture clog zone are generated to simulate fire tests with consideration of moisture clog effect. The temperature distributions of the models predicted from the transient heat analyses are compared with experimental results and show good agreements. In addition, parametric studies are performed with various moisture contents in order to investigate effect of moisture contents on the thermal behaviors of the concrete walls.

Thermal Disinfestation of Stored Grain Insects Using Solar Energy

“…Grain heating time to reach the target temperature of 50 o C is approximately 80 minutes. Interestingly, the temperature profile of the grain bulk is similar to the thermal behavior of reinforced concrete walls after fire exposure in another study (Kang et al, 2016). In the present work, the grain bulk center had much lower temperatures than the peripheral of the grains near the source of the heating coils.…”

Effects of Severe Accident Conditions on Integrity of RPV Pedestal of Fukushima Daiichi Nuclear Power Plant

“…Shah et al (2017) reported the vulnerability of thin elements like slabs whose concrete will spall in post-earthquake fire events, resulting in the melting of reinforcement. Kang et al (2016) reported that the experimental results clearly showed that the temperature measured close to the exposed surface was higher in the thicker walls than that measured at the same location of the thinner walls. This is because the moisture clog inside thick walls with 200 mm and 250 mm thicknesses prevents heat transfer and acts as insulation.…”

A review on research of fire-induced progressive collapse on structures

“…Different reinforcement configurations with different faces of fire exposure studies give a better understanding of their behavior (Song et al , 2019). Cross-section of the member, cover thickness and material quality also play a significant role in the thermal behavior of members (Kang et al , 2016; El-Hawary et al , 1997). The different loading circumstances on the column under temperature effects give different bending behavior (Raut and Kodur, 2011).…”