Search Documents

By A. F. Giamei, F. Landis, M. O. Duffy, R. J. Mador

"The directional solidification of complex advanced gas turbine airfoils must be carried out without the nucleation of undesirable grains and with minimal shrinkage. Such problems are typically eliminated by using a number of mold design and process iterations. A more efficient approach is envisioned where a solidification model is generated and utilized to accelerate process development. Towards this end, the directional solidification (DS) of simple geometrical shapes in a crystal grower apparatus has been simulated with MARC finite element nonlinear thermal analyses.The finite element models of cylindrical (2D) and rectangular (3D) cross-section bars in the DS environment are presented. Temperature dependent properties, the impact of latent heat of fusion and a time-dependent radiation boundary condition constitute the more salient features of the MARC models. Solidification zone thermal behavior is predicted during the withdrawal transient for the specific case of nickel based superalloys grown in ceramic shell molds. Comparisons of analytical results with experiments demonstrate notable prediction accuracy. INTRODUCTIONSingle crystal and uni-directional crystal turbine blades require tightly controlled conditions if metallurgically and mechanically acceptable parts are to be produced. Gated blade geometry and process parameters must be precisely determined if incorrect grain structure, orientation and shrinkage are to be avoided. Since purely experimental development programs designed to evaluate these parameters can be excessively costly and time-consuming, an effort combining engineering analysis and verification by experiment has been initiated at Pratt & Whitney. Comparison of analytical predictions and measured data for geometries simpler than a turbine blade, namely cylindrical and rectangular bars, comprised the initial stage of this effort. Subsequent tasks involve modeling geometries of increasing complexity and ultimately the simulation of the directional solidification of the turbine blade, shown schematically in Figure 1. This paper summarizes the results of the initial stage of the effort."

Jan 1, 1986

By M Oldenburg, P J. Digby, L Nilsson

A constitutive model for the simulation of fracture and fragmentation processes in rapidly loaded rocks is studied. The model was included in a wave propagation finite element code. The results obtained from two different configurations of explosive charge and reflecting surfaces in a plane strain problem were studied. The evolution of the time-dependent fracture pattern is presented.

Jan 1, 1985

By O. E. Wheeler

The term "finite element analysis" is heard and seen in print a great deal these days; a few words on what precisely it is are in order. In the broadest sense, finite element analysis is an application of an idea developed by a nineteenth century mathematician named Rayleigh. His basic idea was to decompose any problem in mathematical physics into a large number of simpler problems, solve the simpler problems, and then put those solutions together to form an approximation to the solution of the original problem. The scheme works nicely because of two features: first, much of the difficulty in solving practical problems of mathematical physics stems from irregularities in the boundaries and the simpler problems can be chosen with regular boundaries and second the smaller problems are solved for small physical areas where simple approximations of the solution do not differ much from the true solution. In the narrower sense, in which we are now interested, finite element analysis is a technique of using imaginary simple structural elements to construct analytical models of real structures. A direct parallel with the Rayleigh approach exists since the "finite elements" have simple boundaries and are restricted to simple behavior within a single element. Although the correspondence between Rayleigh's ideas and finite element analysis is now widely recognized, the computational tool, as it has developed over the last thirty years, comes not from the discipline of physics but rather from that of structural engineering. It is interesting that it came not from the traditional research community, the universities, but instead from working

Jan 1, 1974

By J. G. Henning, R. Edrissi

This paper describes a practical methodology, based on numerical modeling, for the prediction of progressive failure of underground-mine stopes having cable-bolt support. A case study of the 40-761 scope at the Kidd Creek mine, Timmins, Ontario, Canada is presented. Scope 40-761 was mined by blast hole open sloping in 1986 and was a lead scope within a mining block located between levels 36-1 and 38-2. Initially designed to peak at level 38-2, the scope back caved upwards =40 m towards level 36-1. After caving began, cable bolts were installed above the stope from level 36-1. The stope eventually stopped caving when the falling rock mass encountered a sufficiently high cable density. This paper provides details of the geomechanical data and modeling results of the case study. Numerical modeling of cable bolts around the mine stoke was carried out using a finite-element modeling software. The software, known as e-z tools, was developed by the first author.

Jan 1, 1996

By H. Stigzelius

FINLAND'S recent mining history is both dramatic and pitiful in its shifting fortunes, dominated as it has been, by the country's proximity to the border zone of opposing dictatorships and social traditions; Fascism to the south, Communism to the east, and Democracy to the west. After 108 years under Russia's more or less harsh rule, Finland gained its democratic independence during the 1917 revolutionary strife in Russia with the official help of Germany and spontaneous help of other neighbors. The young nation was attacked by Russia in 1939 and again in 1941. It is common knowledge how the Finns fought with everything they had and everything they could get against their overwhelming adversary, and how by force of circumstances they landed in the Axis camp in 1941. Finland has never been known as a mining country in the same way as near-by Sweden, whose abundant iron and copper smelters during long periods so greatly contributed to the nation's welfare. Its largely barren, Archaean-granite geology long seemed forbidding. Some mining was done, to be sure; copper and tin at Pitkaranta near the Russian border, and lead and copper at Orijarvi. But towards the end of the last century the absence of a single producing mine cast a pessimistic shadow of truth over the Finnish poet Runeberg's words, that

Jan 1, 1946

By V. Vahatalo, E. Hakapaa, H. Tanner

Recently modernized, the surface plant of the Outokumpu mine in Finland incorporates a number of ideas meriting close scrutiny from this side of the Atlantic. The mining methods make extensive use of concrete in some unusual ways. Design of the headframe and surface plant represents the latest thinking of European engineers and includes an integral Koepe hoist. The deposit is in eastern Finland, province of North Karelia, 30 miles west northwest of Joensuu and at 60'44' N, latitude. Pyrrhotite, pyrite, chalcopyrite, and sphalerite mineralization occurs in a shear zone in quartzite near a body of serpentinite. Two lenses have a total length over 12.000 ft, with remaining reserves of the 3 to 4 pct Cu ore estimated at about 15 million metric tons.

Jul 1, 1955

By Viswanadham B. V. S., Babu K. V

Wind energy is one of the most economical renewable energy sources. In order to support wind turbines onshore or offshore open-ended monopile foundations are widely used. Unlike conventional structures, wind turbine foundations experience a large magnitude of lateral loads in the order of 20 % to 30% of total vertical loads. The presence of soft clayey layers at shallow depth along the coastal region, offers lesser lateral load resistance to monopile foundations. One option to enhance lateral load capacity is by introducing fins to the outer surface of the monopiles. Studies pertaining to lateral load response of finned piles in clayey soils are very sparse. This paper presents some of the numerical model studies on the lateral load response of monopiles and finned piles in soft and stiff clay. In the present study, three-dimensional finite element analyses were performed on monopiles as well as finned piles. Analyses were performed in clay with different consistency varying from soft to stiff. Pile material is mild steel for all analyses. The pile section modeled as linear elastic material whereas soil was modeled as Mohr – Coulomb constitutive model with non-associated flow rule. Monopiles and finned piles having four and eight fins with different fin sizes and configurations are considered during the analyses. Finned piles advantage over monopiles to resist lateral load is highlighted in the present study. The results have shown that fins are effective to enhance the lateral load carrying capacity of monopiles and also it reduces the bending moment in monopiles for a given design load.

Sep 1, 2022

By Tim Neil, O&apos

Finnish mining traditions date back 400 years. The country was then one of Europe's major iron producers. Most of the mines in current operation, however, were started during the last 20 to 30 years. The Finnish mining industry must make do with limited resources. Deposits are usually low grade and small in size. Open-pit methods are used where possible. But thin ore bodies and harsh winters can impose severe restrictions. Underground mining is often the only option. Despite these handicaps, Finnish metal miners produce copper, nickel, zinc, vanadium, iron ore, cobalt, and ferrochrome. Ironically, the success of Finnish mining is rooted in a crisis the industry faced several decades ago. Mining costs were rising. High grade mineral deposits were nearly exhausted. It was vital that Finland develop new mining machinery and methods that afforded higher productivity. Cooperation between the Finnish mining industry and its equipment manufacturers was good. Partly as a result, the Finnish mining industry has turned itself into one of the most modern and efficient in the world. The Finns did this while continuing to meet the stringent safety and environmental requirements in force in the Nordic countries. Today, the share of domestic raw materials used by the Finnish metallurgical industry is decreasing. So the country increasingly depends on imports of ores and concentrates. To better provide these imports, Finnish mining companies have expanded their foreign operations. And, while importing raw materials, the mining industry has been exporting its technological and equipment know-how and expertise. Mining methods Conventional mining methods and machinery are used in surface mines. Drilling is the exception. It is done with Tamrock hydraulic track drills and 100 to 150 mm-diam (4 to 6-in.-diam) drill holes. Pumpable slurry explosives are used in larger open pits. Underground, sublevel stoping with open stopes is the most common mining method. It accounts for about 80% of all underground stoping. The main benefits of this method are low production costs, high mechanization, and easy control. The best productivity figures exceed 10 t (11 st) per man-hour, including all mining personnel. The development of cable bolting has made it possible to use sublevel open stoping even in relatively weak rock. Cut-and-fill methods, such as concrete-pillar stoping, inclined-wall stoping, and traditional cut-and-fill have also been used, combined with sublevel caving and room-and-pillar methods, according to local demands. Various fill materials and stabilization components have been investigated and tested for cut-and-fill methods. Sublevel open stopes are often later filled, to stabilize the surface or to allow pillar recovery.

Jan 10, 1988

By Fabio Lerbach

The Powder Charcoal Injection in the main burner of the rotary kiln of Pelletizing Plant aims to reduce natural gas consumption and consequently cost reduction with thermal energy. This paper presents the technology, the injection process and the advantages of using powder charcoal to substitute natural gas.

Oct 30, 2017

By D Olivier

De Beers' Finsch Mine is situated in the Northern Cape province, 170 km northwest of Kimberley. The concentrator facility, designed and constructed by Bateman Engineering, was commissioned in 1967 and upgraded in 1979 using diamond liberation and extraction technology available at the time of design. Since then significant advances in diamond processing and technology have been made and these -have been incorporated into the new main treatment plant and recovery plant flowsheets, making diamond liberation and recovery from the Pre-1979 dumps a viable economic option at Finsch."

Jan 1, 2010

By P. den Hoed, R. I. Rambiyana

"Four sulphide minerals - pyrite (FeS2), pyrrhotite (Fe1-xS), pentlandite ([Ni,Fe]9S8), and chalcopyrite (CuFeS2) - contain the base metals and most of the iron in concentrates of platinum group metals (PGMs). In the pyrometallurgical processing of PGM concentrates these sulphides form a matte during smelting, and iron and sulphur are removed from the matte during the converting process. This paper discusses the roasting of Merensky concentrate in air before smelting, with the purpose of reducing the matte load to the converter.Roasting tests were conducted in a bench-scale rotary kiln at temperatures from 350°C to 700°C. The concentrate tested contained 17.4% sulphur and consisted of 23% pyrrhotite, 16% pentlandite, 11% chalcopyrite, and 2% pyrite. The particles were fine (d50 = 22 µm), and all the sulphide particles were liberated. Roasting in air at 550°C and 650°C for 20 minutes removed respectively 60% and 70% of the sulphur. The iron in the sulphides was oxidized to Fe3O4 (magnetite) at temperatures below 500°C and to Fe2O3 (haematite) at temperatures above 550°C. At 700°C the bed sintered and copper oxides formed. At temperatures below 450°C oxidation was incomplete: pyrrhotite remained and only 30% of the sulphur was removed. Smelting tests were conducted to assess matte fall and the deportment of copper and nickel to matte. It was evident that roasting resulted in lower matte falls (a drop of approximately 60%) compared with matte falls from unroasted concentrate. The iron and sulphur levels in the matte were reduced to below 3.5% and 22% respectively.This paper also briefly describes the mechanisms by which pyrrhotite, chalcopyrite, and pentlandite are oxidized during roasting. For chalcopyrite, the mechanism proceeds through an intermediate solid solution phase, which extends from Cu1.02Fe1.04S2 to Cu2.04Fe0.72S2 to a copper-rich solid solution of bornite (Cu4Fe1.4S4-Cu2S). The oxidation of pentlandite proceeds through a monosulphide solid solution (Ni0.39Fe0.53S-Ni0.74Fe0.15S) to a solid solution of heazlewoodite ([Ni,Fe]3}xS2). These mechanisms are explored in relation to chemical thermodynamics and microstructures."

Jan 1, 2015

By Jose a. Sanchidrian, Ramon G. Eguren, Javier L. Amigo

On December 2013 a MEMU exploded at a blasting site in Norway, after burning for more than two hours. This paper describes the analyses made to determine the actual yield of the explosion, the lessons learned from the event and the actions taken as a consequence. The conclusions of the analysis were the following: - The yield of the explosion was 650-1450 kg TNT. In terms of AN and ANE they correspond to 1300 – 3700 kg AN, or 950 – 2450 kg ANE or ANE/AN blend. These quantities are 8 to 31 % of the explosive precursors in the truck. The burning of the truck and its load for two and a half hours had consumed more than two thirds (perhaps up to 90 %) of the explosive precursor material.

Jan 1, 2016

By C MacDonald

There are many technologies available today in terms of fire and life safety in road tunnels. So many in fact that it is becoming more and more difficult for clients and contractors alike to determine what they want and what they need. From a clientÆs perspective, fire and life safety is about protection to its infrastructure and to the public at large. Conversely, the contractor is looking to meet its æfit for purposeÆ or ædeem to complyÆ requirements in the most economic and practicable way. Practices regarding fire and life safety in road tunnels have undergone a degree of transformation during the last decade or more throughout the world. This transformation has largely been driven by a series of catastrophic accidents such as the major fires in Europe including the Mont Blanc Tunnel, Tauern Tunnel, Saint-Gothard Tunnel, and now most recently in the CityLink Tunnels in Melbourne. International guidelines produced by organisations such as the Permanent International Association of Road Congresses (PIARC), the European Union, the International Tunnelling Association (ITA) and the US National Fire Protection Authority (NFPA) now provide clients, owners and designers with the tools required to define and specify the required fire and life safety systems in road tunnels. The majority of these tools are based on risk assessment and risk management. Recent road tunnel projects within Australia, however, have not referred solely to such guidelines. Clients have opted to prescribe different or additional fire and life safety requirements within the projectÆs technical specification documentation (project requirements), leaving designers and contractors with little room to implement alternatives or substitutions. Further, these project requirements are largely dictated by practice established on previous road tunnel projects within Australia. This paper looks at the current international guidelines and practices and undertakes a comparison with the EastLink tunnels in Melbourne and other road tunnels within Australia and makes assessment on whether Australian methods are the most appropriate for clients and contractors alike. Focus is directed to the key elements of fire and life safety such as:traffic envelope, barrier arrangements and emergency walkway provisions;deluge systems;drainage systems;fire rating requirements;tunnel ventilation systems;cross passage provisions;fire safety assessment;critical intelligence systems including help phones, CCTV, incident detection, tunnel signage, etc; andexternal tunnel control systems.

Jan 1, 2008

By F. Habashi

The first documentary evidence for the use of fire to extract a metal was furnished by the wall paintings of the ancient Egyptians showing workers using the blowpipe and bellows to increase the temperature to melt gold in a crucible. Furnaces grew in size and complexity, coke replaced charcoal in the blast furnace, and the Industrial Revolution took place in England that gradually spread worldwide. More metals became known and new techniques were introduced for their extraction. Among these, metallothermic reactions became prominent in the nineteenth century immediately after the discovery of the electric current and its use to liberate the alkali metals from their salts. Once these metals became available, they were used to produce aluminium from alumina that resisted all other methods of attack. Aluminium, now available on a large scale, was used to decompose the most stable compounds and liberate more metals that became the basis of modern civilization.

Jan 1, 2004

By J. -M. Lopez-Cuesta, C. Petter, B. Otazaghine, M. Batistella, R. Sonnier

"Kaolinite is a dioctahedral aluminosilicate widely used as paper filler and coating pigment. At the best of our knowledge, kaolinite is not widely used in polymer industry. Therefore, in this study, the flame retardant effect of kaolinite in ethylene vinyl acetate copolymer (EVA) and polypropylene (PP) were studied and compared with an alumina trihydrate (ATH) and Talc. Cone calorimeter results shows that the weight percentage of ATH in EVA/ATH composites must be at least 50 wt. % in order to reach an improvement in fire retardancy in terms of pHRR. In the case of EVA/kaolinite, even with 35 wt. % the pHRR is largely reduced. Comparing PP/Talc and PP/kaolinite composites at 30 wt. %, both fillers leads to same reduction in pHRR with a slightly better performance for PP/kaolinite composites. In both cases an intumescent behavior of kaolinite composites was observed that could slow the rate of the rising degradation products, allowing radical recombination reactions. Also, it was observed that kaolinite forms a protective layer on the surface of the samples, which could insulate the material. These behaviors (intumescence and formation of a protective barrier) could reduce the transfer of the degradation products to the flame and explain the better performance of kaolinite composites. INTRODUCTION The use of mineral fillers as fire retardants in polymer matrix are well known and widely studied [1]–[10]. Aluminum and magnesium hydroxides (respectively ATH and MDH) are the most widely used inorganic fire retardants. To achieve fire retardancy with these mineral fillers, about 50-60% loading is required which decrease the physical properties of the composites. The fire behavior of composite EVA has been the subject of many studies [4], [7], [9]–[15]. EVA copolymers are commonly used in the cable industry, due to their high ductility, even at high loading rates. In such applications, the flame retardant systems should be introduced into the polymer to improve the fire reaction. Many flame retardant systems have been tested but the most used industrially relates to formulations based on hydrated mineral fillers (aluminum hydroxide and magnesium hydroxide). Their low cost and reduced fumes generation explains their success. However, to obtain good performance with this type of flame retardants, it is necessary to incorporate high levels (up to 65 wt %), which severely impact other properties such as processability and mechanical behavior. The main modes of action of these flame retardants are the dilution of the gas phase, the endothermic decomposition and a barrier effect created by the inorganic oxide residue which may be improved by the incorporation of other components such as montmorillonites, silicas or talcs."

Jan 1, 2015

By A Sturgess, P McKenna, P D. Erskine, D Doley, V C. Glenn

For more than four decades, rehabilitated lands in the Bowen Basin have been planted with buffel grass (Cenchrus Ciliaris), which is often used to provide rapid, stabilising and erosion reducing cover to reshaped landforms (Erskine and Fletcher, 2013; Harwood, Hacker and Mott, 1999; Grigg, Shelton and Mullen, 2000; Naidu et al, 1997). Historically introduced to Central Queensland and encouraged by pastoralists in the early 1900s (Humphreys, 1967), the species has been extensively used by mine managers in seeding mixes (Coaldrake and Russell, 1970; Edye, 1975), and the invasive nature of the grass has led to the monodominance in rehabilitated areas of semi-arid Central Queensland. With 40 open cut coalmines in Central Queensland (Department of Natural Resources and Mines, 2015), a considerable amount of land is either disturbed mine footprint (156 200 ha) or rehabilitated (29 200 ha) (Dale, 2015), and the bulk of rehabilitation consists of relatively young (<30-year-old) developing ecosystems, with demonstrated biomass fuel loads up to 20 t/ha (Grigg, Shelton and Mullen, 2000).Uncontrolled fire poses a significant risk to rehabilitated landforms that are located in close proximity to mining infrastructure, neighbouring communities, open pits with exposed flammable coal seams and flammable stockpiled coal resource. Mine lease holders in Queensland have the added responsibility of managing and protecting any endangered regional ecosystem communities, and flora and fauna listed federally under the Environment Protection Biodiversity and Conservation Act 1999 or the State Vegetation Management Act 1999; as well as, any culturally significant sites such as scar trees or middens that are found on-site. Additionally, uncontrolled fire in rehabilitated landscapes poses a significant risk to mine site closure goals, with the potential to create altered states and stalled ecological trajectories (Grant, 2006). CITATION:McKenna, P, Glenn, V, Erskine, P D, Doley, D and Sturgess, A, 2016. Fire behaviour in buffel grass dominated mine site rehabilitation in Central Queensland, Australia, in Proceedings Life-of-Mine 2016 Conference , pp 158–162 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By Negar Elhami Khorasani, Anthony Tessari, Nan Hua

Fire hazards can cause severe and irrecoverable damage to reinforced concrete (RC) tunnel linings, threatening the serviceability and resilience of transportation networks. This paper first examines the existing methodologies that are used to classify damage to tunnel linings from fire. These approaches are then supplemented with the results of advanced modeling and inputs from industry experts to propose new fire damage/ repair classifications with the associated thresholds. The results of the presented research can be used to guide fire risk assessment as well as the performance-based design of tunnel fire protection.

Jun 13, 2023

By Maria I. De Rosa

Table 1 and figure 1 show the number of fires and fire in¬juries that occurred in underground coal mines by state during 1990-1999. Table 1 also shows by state the risk rates, employ¬ees' working hours, lost workdays, and coal production. Over¬all, 87 fires occurred in 12 states. Twenty-seven of those fires caused 34 injuries (the yearly average was 8.7 fires and 3.4 injuries). One fire and one injury involved a contractor. The underground mine fires required 25 mine rescue team interventions and 30 mine/section evacuations followed by 13 mine/section sealing/flooding/CO2/N2, gas injections. The Ewhr value was 1,003 x 106 hr (In = 0.007), the CP value was 4,008 x 106 st (Frr = 0.022), and the LWD value was 208. Virginia had the most fires (15 fires and 7 injuries). Pennsyl¬vania had the most fire injuries (12 fires and 9 injuries), fol¬lowed by Kentucky (12 fires and 6 injuries), and Alabama (12 fires and 4 injuries). Among these states, Alabama had the highest fire risk rate value (Frr = 0.073), whereas Pennsylvania had the highest injury risk rate value (In = 0.016). Table 2, partly illustrated in figure 2, shows by time period the number of fires, fire injuries, risk rates, employees' working hours, lost workdays, and coal production. The number of fires and fire injuries show a decrease followed by an increase during the five time periods (see table 2 and figure 2). This was ac¬companied by a decline in employees' working hours throughout the periods and an overall small decrease in coal production. The In and Frr values follow patterns similar to those shown by the fire and injury values. By comparison, data from Pomroy and Carigiet [1995] show that during 1978-1992 a total of 11 states were involved in 164 underground coal mine fires (yearly average, 10.8) with 43 injuries (yearly average, 2.9) and 27 fatalities (yearly average, 2; however, the 27 deaths occurred during a single fire caused by an overheated air compressor [MSHA 1984]). The CP value was 5,340 x 106 st (yearly average, 356 x 106 st) (Fn = 0.031). Data on employees' working hours and injury risk rates were not available. Tables 3-8 show the number of fires by ignition source, method of detection and suppression, equipment involved, location, and burning material by time period. Figure 3 shows the major variables during 1990-1999. Table 9 shows the number of fire injuries per number of fires causing injuries and total fires by year, ignition source, equipment involved, and location.

Jan 1, 2004

By Maria I. De Rosa

Table 1 and figure 1 show the number of fires and fire injuries that occurred in underground metal/nonmetal and stone mines by state during 1990-2001. Table 1 also shows the injury risk rates, employees' working hours, and lost workdays. Overall, 65 fires occurred in 20 states; these include 2 fires and no injuries for contractors. Six of the fires caused nine injuries. The yearly average was 5.4 fires and 0.75 injury. Forty-one fires with 2 injuries occurred in metal mines, 14 fires with 7 injuries occurred in nonmetal mines, and 10 fires with no injuries occurred in stone mines. The underground mine fires required 25 mine rescue team interventions and 30 mine/section evacuations. The Ewhr value was 260 x 10° hr (Irr = 0.007), and the LWD value was 83. Idaho had the most fires (eight fires and no injuries), followed by Louisiana (seven fires and two injuries), Michigan (six fires and six injuries), and Missouri (six fires and no injuries). Of these states, Michigan had the highest injury risk rate value (Irr = 0.146). Table 2, partly illustrated in figure 2, shows the number of fires, fire injuries, risk rates, employees' working hours, and lost workdays by time period. The number of fires during the six time periods show an increase during the fourth period followed by a sharp decrease during the fifth period and a sharp increase in the last period. The number of fire injuries show an increase followed by a decrease during most of the periods, accompanied by a decline in employees' working hours during most of the periods; an increase is seen during the third and fourth periods. The In values follow patterns similar to those shown by the injury values. Tables 3-8 show the number of fires by ignition source, method of detection and suppression, equipment involved, location, and burning material by time period. Figure 3 shows the major variables related to fires for 1990-2001. Table 9 shows the number of fire injuries per number of fires causing injuries and total fires by year, ignition source, equipment involved, and location.

Jan 1, 2004

"A fire design innovation of the concrete lining of the Ohio River Bridges East End Crossing Tunnel has been developed. As a result from a fire suppression and tunnel ventilation system, the project design Heat Release Rate (HRR) was able to be constrained from 300 MW to about 50 MW. With this reduced HRR, concrete lining without passive fire protection may be acceptable, if the tunnel concrete lining will not result in explosive spalling during the designed fire event. Concrete explosive spalling test was proposed to verify this assumption. Since no standard concrete fire explosive spalling testing procedure exists, a project specific testing procedure was developed and fire tests conducted. From fire test results, it is concluded that the proposed tunnel concrete lining, in conjunction with the proposed fire suppressing and ventilation system, will not experience explosive spalling and does not require a passive fire protection system. INTRODUCTION The Ohio River Bridge East End Crossing Tunnel is part of a Public Private Partnership project, which connects transportation network between Louisville, Kentucky and southern Indiana. Located in Louisville, Kentucky, the twin-tube highway tunnel provides northbound and southbound lanes of the Kentucky approach to a new bridge across the Ohio River. Tunnel lengths are approximately 1,675-ft and 1,685 for the northbound tube and the southbound tube, respectively. Connected by two cross-passages, both tubes have a roadway width of 40-ft, for 3-lane traffic, and a vertical clearance of 26.5-ft.The Tunnel was constructed by drill and blast method with shotcrete and rock dowels as initial ground supports. The final tunnel lining consists of 16 inches cast-in-place concrete lining and 20 inches invert slab, with a waterproofing system around the tunnel perimeter. Two (2) tunnel side drains and one (1) invert drain were provided for each tube. This paper describes the rational in assessing fire design requirements of the tunnel final concrete lining, to answer the question whether a passive fire protection system is needed or not."

Jan 1, 2016