An analysis of tunnel fire characteristics under the effects of vehicular blockage and tunnel inclination

Date

2018-09-01

Author

SHAFEE, SINA
Yozgatlıgil, Ahmet

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

221
views

0
downloads

It is known that the blockage and inclination conditions of tunnels are among the important factors affecting fire safety considerations, as these factors could change the characteristics of possible fire incidents as well as smoke movement in tunnels. In the present work, we analyze the variations of the tunnel fire burning rate, heat release rate and smoke backlayering as being functions of these two factors. Ethanol pools were used as fire sources in a reduced scale tunnel model with longitudinal ventilation ranging between 0 and 1.5 m/s. The blockage ratio of the tunnel, which was defined as the ratio of the cross-sectional area of the blockage to that of the tunnel, was tested under three cases: 0% (i.e., no blockage), 14% and 56% blockage. The latter two blockage ratios respectively correspond to that of a typical small vehicle and a railroad carrier. The tunnel inclination grade was varied between -6% and +3% to represent uphill and downhill slopes. Numerical simulations were also performed using Fire Dynamics Simulator (FDS) to rationalize some of the experimental results. Measurements and predictions indicated that the blockage affects the burning rate of tunnel a fire due to changes in the air entrainment at wake flow, local ventilation over the fire and flame dragging. Increasing the ftre-blockage separation distance had an adverse effect on the burning rates. The temperature results emphasized the effect of blockages on tunnel ceiling temperatures, which increased as high as 300% compared to that of the no blockage case. The results indicated the major effects of the tunnel sloping grade on the fire heat load as well as the tunnel ceiling temperature. The critical ventilation velocity was achieved in the range of 0.75-1.25 m/s for the limiting cases of -6% and +3% tunnel inclination, for which a fit was proposed as a function of inclination grade. Finally, a statistical model based on an analysis of variance approach was applied on the obtained results, which demonstrated that among the factors contributing to the fire heat release rate variations in this study, the ventilation velocity accounted for 45% of the variation, followed by tunnel blockage at 25%, and inclination at 19%.

Subject Keywords

Geotechnical Engineering and Engineering Geology, Building and Construction

URI

https://hdl.handle.net/11511/42357

Journal

TUNNELLING AND UNDERGROUND SPACE TECHNOLOGY

DOI

https://doi.org/10.1016/j.tust.2018.05.019

Collections

Department of Mechanical Engineering, Article

Suggestions

OpenMETU
Core

An approximate procedure for estimating the member demands in mid-rise reinforced concrete buildings Akpinar, Ugur; Binici, Barış; Yakut, Ahmet; Tuncay, Kağan (Springer Science and Business Media LLC, 2020-01-01) Seismic assessment of mid-rise reinforced concrete buildings is important for urban seismic risk reduction. Nonlinear time history analysis is the state-of-the-art analysis tool for this purpose. However, the number of such buildings may reach to several tens of thousands in metropolitan cities of earthquake prone countries. This necessitates faster yet sufficiently accurate assessment methods to mitigate the seismic risk. In this study, a simple and efficient approach is developed and validated for the ass...
A screening procedure for seismic risk assessment in urban building stocks Sucuoğlu, Haluk; Yakut, Ahmet (SAGE Publications, 2007-05-01) An effective step for seismic risk mitigation in large urban areas under high seismic risk is to identify the most vulnerable buildings that may sustain significant damage during a future earthquake. Once they are identified properly, existing seismic risks may be reduced either by retrofitting such buildings, or by replacing them with new buildings in view of a particular risk-mitigation planning strategy. A fast and simple seismic risk-assessment procedure for vulnerable urban building stocks is proposed ...
Economic assessment of the seismic retrofitting of low-cost apartment buildings Arıkan, Mehmet Fırat; Macit, G (Informa UK Limited, 2005-07-01) When structural retrofitting of buildings is required due to seismic safety considerations, building owners or government officials are faced with a crucial decision whether to demolish and rebuild their buildings, or retrofit them. Simple decisions based on fixed proportions, such as demolish and rebuild if retrofit costs exceed 40% of the replacement cost, may be misleading. A financial analysis should be carried out considering all the revenues and costs of the building during its life time. A low-cost r...
Prediction of damage in R/C shear panels subjected to reversed cyclic loading Hindi, R; Mansour, M; Dicleli, Murat (Informa UK Limited, 2005-01-01) In this paper, the damage prediction of shear-dominated reinforced concrete (RC) elements subjected to reversed cyclic shear is presented using an existing damage model. The damage model is primarily based on the monotonic energy dissipating capacity of structural elements before and after the application of reversed cyclic loading. Therefore, it could be universally applicable to different types of structural members, including shear-dominated RC members. The applicability of the damage model to shear-domi...
Effect of modifying bearing fixities on the seismic response of short- to medium-length bridges with heavy substructures Hindi, R; Dicleli, Murat (SAGE Publications, 2006-02-01) The effect of modifying the fixity conditions of the bearings on the seismic response and vulnerability of existing bridges with heavy substructures is studied. For this purpose, nonlinear seismic analysis of a typical bridge with heavy substructures is conducted to assess its seismic response and vulnerabilities. Next, the bearings are modified to obtain four different configurations of bearing fixities over the substructures. Nonlinear seismic analyses of the bridge are conducted to assess its seismic res...

Citation Formats

S. SHAFEE and A. Yozgatlıgil, “An analysis of tunnel fire characteristics under the effects of vehicular blockage and tunnel inclination,” TUNNELLING AND UNDERGROUND SPACE TECHNOLOGY, pp. 274–285, 2018, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/42357.