Temperature Distribution Characteristics of Concrete during Fire Occurrence in a Tunnel

Abstract

Fire in a tunnel or an underground structure is characterized by a rise in temperature above 1000 °C in 5–10 min, which is due to the characteristics of the closed space. The Permanent International Association of Road Congresses has reported that serious damage can occur in an underground structure as a consequence of high temperatures of up to 1400 °C when a fire accident involving a tank lorry occurs in an underground space. In these circumstances, it is difficult to approach the scene and extinguish the fire, and the result is often casualties and damage to facilities. When a concrete structure is exposed to a high temperature, spalling or dehydration occurs. As a result, the cross section of the structure is lost, and the structural stability declines to a great extent. Furthermore, the mechanical and thermal properties of concrete are degraded by the temperature hysteresis that occurs at high temperatures. Consequently, interest in the fire safety of underground structures, including tunnels, has steadily increased. This study conducted a fire simulation to analyze the effects of a fire caused by dangerous-goods vehicles on the tunnel structure. In addition, a fire exposure test of reinforced-concrete members was conducted using the Richtlinien für die Ausstattung und den Betrieb von Straßentunneln (RABT) fire curve, which is used to simulate a tunnel fire.

Temperature Distribution Curve Analysis on Concrete through LS-DYNA

“…The International Tunneling Association (ITA) establishes guidelines for tunnel safety, particularly regarding heat emission and fire duration, to safeguard tunnel structures from fire incidents. These guidelines recommend maintaining a maximum allowable temperature of 380 • C to prevent concrete structure deterioration [32,33]. In both cases, the temperature is over the ITA's permissible limit of 380 • C in the experiment and simulation with the different concrete depths.…”

A review on behavior, material properties and finite element simulation of concrete tunnel linings under fire

“…The German Ministry of Transport developed RABT fire curve in 1985 for both railway and highway tunnels as a part of the Eureka project (Kim et al, 2019;Lönnermark, 2005). Temperature of RABT curve rises to 1200°C within 5 minutes of fire exposure at a sharp gradient of 240°C/min, then it remains constant at 1200°C until 30 minutes and 60 minutes respectively for highway and railway tunnels.…”

Special Issue on “Buildings and Structures under Extreme Loads”

“…In conclusion, it is known that both man-made attacks and accidents can yield to explosions and fire loads that could push the constructional materials, and thus the structures, to their capacity limits. Blast loads analyses, in this regard, are reported in [18][19][20], while fire effects on a tunnel structure are analyzed in [21].…”