Fire tests of cut and cover tunnel roof segments at positive moment region

Download
2011
Arsava, Kemal Sarp
The most important issue during a tunnel fire is safety of human life. The tunnel fire structural research and investigations have gained more importance in the last decade but studies show variable results depending on the concrete quality and tunnel design fire. For instance, a certain type of concrete with high moisture content can tend to explode in the first 10-15 minutes of fire with rapid increase of heat release rate. A sudden collapse of the tunnel roof during the fire is unacceptable. Especially in Netherlands, the possible sagging of cut and cover tunnel roof is undesired and prevention systems are applied. The main purpose of this research is to investigate fire response of the positive moment region of cut and cover tunnel roof through an experimental and analytical program without use of any protection. In this context a standard one cell rail road cut and cover tunnel has been designed for loads of backfill, lateral earth pressure and self weight. The typical concrete cover used in Turkish railroad tunnels is 6 centimeters. Four pairs of representative sample tunnel roof segments have been manufactured and only one segment out of each pair are tested under 2 hours extreme design tunnel fire in a furnace. Out of these four types, two types have been internally pre-stressed to simulate the internal loads at the positive moment region of the tunnel roof. Four pairs of sample segments are simply supported during the static load test and static load is applied at the mid-span to measure the difference in the post-fire structural performance. Compressive strength of concrete, tensile strength of reinforcing bars, electron microscope evaluation of concrete, moisture content of concrete are recorded during the test program. A finite element based solution is developed to simulate the results of static load tests. Post-fire structural performances of burnt segments are observed to be not much different than the unburnt segments.

Suggestions

3D forest fire propagation simulation
Koese, Kivanc; Grammalidis, Nikolaos; Yılmaz, Erdal; Cetin, Enis (2008-05-30)
The increase in the number of forest fires in the last few years dispatch governments to take precautions. Besides prevention, early intervention is also very important in fire fighting. If the firefighters know where the fire will be in some time, it would be easier for them to stop the fire. Therefore a big need for simulating the fire behavior exists. In this paper we are proposing a system which can simulate the propagation of fire in time. Also this system can visualize the propagation of fire in any 3...
An experimental study on the burning rates of interacting fires in tunnels
SHAFEE, SINA; Yozgatlıgil, Ahmet (2018-03-01)
Multiple fires may occur in close proximity in process industries, power generation and fuel storage facilities and confinement conditions such as tunnels, which can lead to a considerable alteration in fire characteristics and safety design. The topic is of significant importance to the fire safety research because there is little work in the literature that investigates the case of interacting fires, which have a destructive potential. In this work, we study the effects of an adjacent fire source on the b...
An experimental study on the effects of blockage ratio and ventilation velocity on the heat release rate of tunnel fires
Kayili, Serkan; Yozgatlıgil, Ahmet; Cahit Eralp, O. (SAGE Publications, 2011-8-26)
It is very important to accurately predict the fire-induced air velocity, temperature, and smoke concentrations in tunnel fires to design efficient fire protection systems. In this study a scaled model of a tunnel was constructed based on Froude number scaling and wood sticks with different configurations which were burned in a controlled environment. Model vehicles having a square base were built according to the wood crib theory. The impact of varying longitudinal ventilation velocity and the cross-sectio...
Structural fire performance of concrete and shotcrete tunnel liners
Caner, Alp; Munfah, N (2005-12-01)
Tunnel liners can suffer significant structural damage when exposed to long duration fires. The resulting damage to the tunnel liner can produce casualties, major service disruptions, and financial loss. Structural fire performance studies have generally focused on buildings exposed to standard fires. Tunnel fires typically have high temperatures and heat release rates compared to building fires. In this paper, an analytical method is provided for assessing the structural fire performance of concrete or the...
An Experimental and numerical study on the combustion characteristics of pool fires in tunnels
Shafee, Sina; Yozgatlıgil, Ahmet; Department of Mechanical Engineering (2017)
This work presents the results of experimental and numerical analysis on tunnel fires in an attempt to improve existing knowledge on the fire dynamics and related safety measures in various tunnel fire scenarios. Results are grouped into four parts in which the effects of tunnel wall coating, inclination, tunnel obstruction and existence of secondary fire source in close vicinity were investigated on tunnel fire characteristics. A 1/13 longitudinally ventilated scaled tunnel model constructed based on Froud...
Citation Formats
K. S. Arsava, “Fire tests of cut and cover tunnel roof segments at positive moment region,” M.S. - Master of Science, Middle East Technical University, 2011.