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Articles 10081 - 10110 of 13031

Full-Text Articles in Engineering

Improving The Ventilation Efficiency Of Jet Fans In Longitudinally Ventilated Rectangular Ducts, Eddy Jacques, Pierre Wauters Jun 1999

Improving The Ventilation Efficiency Of Jet Fans In Longitudinally Ventilated Rectangular Ducts, Eddy Jacques, Pierre Wauters

U.S. Mine Ventilation Symposium

The performance of a jet fan in a longitudinally ventilated tunnel is significantly reduced by the proximity of wall or ceiling where important shear stress losses occur. The paper focuses on the effect of jet fan inclination on the reduction of these losses; reducing losses means improved installation efficiency manifested by increased ventilation flow for the same fan power input. Experimental tests were carried out on a model at scale 1/5.5th. They allow one to determine the optimal jet pitch angle and the resulting benefit that could be drawn out of this solution in the case of tunnels …

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Evaluation Of Different Airflow Sensors At The Wipp Facility, Kirk Mcdaniel, Ian J. Duckworth, Brian S. Prosser Jun 1999

Evaluation Of Different Airflow Sensors At The Wipp Facility, Kirk Mcdaniel, Ian J. Duckworth, Brian S. Prosser

U.S. Mine Ventilation Symposium

The Waste Isolation Pilot Plant (WIPP) is an U.S. Department of Energy underground disposal facility designed to permanently and safely isolate U.S. defense-generated transuranic radioactive waste. The underground ventilation system is engineered to minimize the release of radioactive contamination to the environment in the event of an accident. During 1994 an extensive ventilation remote monitoring and control system was installed. It consists of fifteen air velocity sensors, eight differential pressure stations, automated control features on key underground air regulators, and eight psychrometric stations. The airflow monitoring component of the system has been a problem since the original installation. Due to …

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Axial Fan Monitoring By Pressure Transients Close To The Blades, A Preliminary Study, Ian Loomis, Shaun Ramsay Jun 1999

Axial Fan Monitoring By Pressure Transients Close To The Blades, A Preliminary Study, Ian Loomis, Shaun Ramsay

U.S. Mine Ventilation Symposium

As the axial fan blades move within the fan case pressure transients are developed, which can be measured and qualified by a fixed point monitor. The nature of the pressure transient pattern observed close to the fan blade varies with the location on the fan performance curve. Measurement of the pressure fluctuation around the fan blade ring reveals the minute variation in pressure associated with the movement of the air within the fan. Such observations could be the basis for an on-line fan monitoring system based on the acoustic emissions from the fan blade. This paper describes a preliminary study …

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Validation Of Computational Models Of Auxiliary Ventilation Systems With Experimental Data, K. W. Moloney, D. M. Hargreaves, I. S. Lowndes, W. Pearce Jun 1999

Validation Of Computational Models Of Auxiliary Ventilation Systems With Experimental Data, K. W. Moloney, D. M. Hargreaves, I. S. Lowndes, W. Pearce

U.S. Mine Ventilation Symposium

This paper reports the interim findings of a research program whose objective is to determine whether Computational Fluid Dynamic (CFD) models can be employed to accurately predict the airflow patterns within rapid development headings. In particular, the project aims to investigate the optimum set back distances for the ducts in order to adequately ventilate the face of the drivage. To validate the accuracy of the CFD model simulations measurements were obtained from a series of experiments performed on both scale models and within a full-scale surface gallery. The experimental scale-modeling program included making a series of pressure measurements across the …

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Simulation Of Airflow Expansion Requirements For An Exhaust Raise Common To Two Mines, Eurel De Souza, László Götz Jun 1999

Simulation Of Airflow Expansion Requirements For An Exhaust Raise Common To Two Mines, Eurel De Souza, László Götz

U.S. Mine Ventilation Symposium

A complex raise system managed by Battle Mountain Canada Ltd. serves as a main exhaust ventilation airway system for two mines, Golden Giant mine and David Bell mine. Increased exhaust airflow requirements associated with new orebody development at Golden Giant mine have necessitated a study to investigate the feasibility of expanding the exhaust raise system capacity while maintaining exhaust requirements at David Bell. This paper describes a complex ventilation study aimed at optimizing exhaust ventilation conditions for the raise system common to the two operating mines.

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Environ 2.5 — A Mine Ventilation And Cooling Network Simulation Tool, W. M. Marx Jun 1999

Environ 2.5 — A Mine Ventilation And Cooling Network Simulation Tool, W. M. Marx

U.S. Mine Ventilation Symposium

As mining operations progress, ore reserves are depleted and alternative are almost invariably found at increasing depth and a host of attendant difficulties in this regard face· the mine operator. Most significant among these is the control of the increasingly hostile environment encountered at depth in terms of both ground behaviour and the increasing hot environment. To enable the practical and economical design of mine ventilation and cooling systems, ventilation practitioners need effective and efficient tools to perform their duty. One such tool is the Environ 2.5, an interactive network simulation program that allows for the simultaneous simulation of airflow …

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Genetic Algorithm Optimization Of A Large U.K. Coal Mine Ventilation Network, Zhi-Yuan Yang, I. S. Lowndes, B. Denby Jun 1999

Genetic Algorithm Optimization Of A Large U.K. Coal Mine Ventilation Network, Zhi-Yuan Yang, I. S. Lowndes, B. Denby

U.S. Mine Ventilation Symposium

This paper reports on results of an application of a genetic algorithm to the optimisation of a large UK Coal Mine Ventilation Network. The genetic algorithm technique has been developed into a computer program for minimising the total network operating fan power costs. The application of booster fans may become an attractive alternative for ventilation engineers to provide an adequate supply of fresh air around the working areas in some deep and/or extensive mines. The objective of this research is to minimize the total power consumption of a ventilation system by determining the optimum combinations of (1) main fan and …

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Msha Approval Process, David C. Chirdon Jun 1999

Msha Approval Process, David C. Chirdon

U.S. Mine Ventilation Symposium

The hazardous nature of the underground mining environment necessitates the use of equipment and mining products designed to ensure safe usage in this hostile environment. Title 30, code of federal regulations (30 CFR) includes requirements that all equipment and products intended for use in potentially gassy areas of underground mines be approved by the mine safety and health administration (MSHA). Design and performance requirements for many of the products intended for use in the underground environment are also part of 30 CFR. This paper describes the processes available to potential applicants for obtaining MSHA approval. Emphasis is placed on ventilation-related …

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Ventilation Optimization — Balancing The Need For More Power Against Environmental Concerns, Stephen G. Hardcastle, R. D. Lamond, D. T. Willoughby Jun 1999

Ventilation Optimization — Balancing The Need For More Power Against Environmental Concerns, Stephen G. Hardcastle, R. D. Lamond, D. T. Willoughby

U.S. Mine Ventilation Symposium

This paper shows how the Nanisivik mine was able to improve the underground working environment, decrease operational costs, and reduce its impact on the environment through optimizing their ventilation system. Through re-organizing their ventilation system, the overall flow through the mine increased by at least 20%, and local flows increased by over 100%. This change also resulted in a 45% reduction of fan motor power. And as a consequence of reduced power demands the mine has decreased its Green-house gas (GHG) emissions. Currently, ventilation is typically responsible for 40% of a Canadian mine's underground electrical consumption. This could dramatically change …

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Mine Safety In Chinese Coal Mines: Today And Tomorrow, Xintan Chang, Yunxiu Sai Jun 1999

Mine Safety In Chinese Coal Mines: Today And Tomorrow, Xintan Chang, Yunxiu Sai

U.S. Mine Ventilation Symposium

As a result of governmental agency restructuring, China's coal industry has been going through evolutionary changes as well in recent years. This paper discusses the various structural changes within the former Ministry of Coal Industry (MOCI) that occurred recently and its impact on coal production, health and safety regulation enforcement, safety training, and higher education.

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Equivalent Roughness And Its Application In Calculating Friction Drag Of Mine Roadway, Yan Zhou, Xingshen Wang Jun 1999

Equivalent Roughness And Its Application In Calculating Friction Drag Of Mine Roadway, Yan Zhou, Xingshen Wang

U.S. Mine Ventilation Symposium

Some roadways, which do not behave as "wholly rough pipe" as we expected, will have different impact on airflow in a mine ventilation network because of the low Reynolds numbers. For a "non-Wholly-rough" roadway, its resistance factor (R) or the friction factor (¦) is not only dependent upon the relative roughness but also dependent upon the Reynolds number, which varies directly as the flow rate. In this case, R or ¦ is no longer a constant independent of flow rate. Thus, in order to correctly calculate the friction drag of the same roadway for different flow rates, ¦ must be …

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Modelling Of The Occurrence Of Hydrogen Sulphide In Coal Seams, A. D. Stewart Gillies, Mehmet S. Kizil, Hsin Wei Wu, Timothy J. M. Harvey Jun 1999

Modelling Of The Occurrence Of Hydrogen Sulphide In Coal Seams, A. D. Stewart Gillies, Mehmet S. Kizil, Hsin Wei Wu, Timothy J. M. Harvey

U.S. Mine Ventilation Symposium

Hydrogen Sulphide (H2S) has been encountered within a number of Bowen Basin collieries, Central Queensland, Australia. High concentration occurrence during mining of a longwall panel raises a number of potential problems, which demand greater understanding to allow efficient mining while maintaining safe and healthy environmental conditions. Longwall panels at Mine A and Mine B have recently mined through H2S zones. The high H2S zone mined through at Mine A was wide and covering the whole length of the face comparing to the narrow H2S zone which was cutting the panel at 45° …

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Characteristics Of Airborne Dust In The Return Airways Of The Mechanized Longwall Face, Tevfik Güyagüler, Sinan Keskin Jun 1999

Characteristics Of Airborne Dust In The Return Airways Of The Mechanized Longwall Face, Tevfik Güyagüler, Sinan Keskin

U.S. Mine Ventilation Symposium

In this paper the results of a research study on the characterisation of airborne dust in the return airway of the mechanized longwall face at Middle Anatolian Lignite Mine, OAL are presented. Dust, temperature, moisture and air velocity measurements were carried out in the return airways of the fully mechanized longwalls. Then the analyses of results on real-time concentration data, mass concentration data, effect of moisture, heat and air velocity on dust concentration are made. It has been found that amount of dust in return airway is directly related to the face activities and to the amount of settled dust …

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Mitigation Of Methane Emissions From Coal Mine Ventilation Air, Peter Carothers, Milind D. Deo Jun 1999

Mitigation Of Methane Emissions From Coal Mine Ventilation Air, Peter Carothers, Milind D. Deo

U.S. Mine Ventilation Symposium

U.S. EPA's coalbed methane outreach program, (CMOP) has prepared a technical assessment of techniques that combust trace amounts of coal mine methane contained in ventilation air. Control of methane emissions from mine ventilation systems has been an elusive goal because of the magnitude of a typical airflow and the very low methane concentrations. One established and cost-effective use feeds the air into a prime mover in lieu of ambient combustion air. This method usually consumes just a fraction of the flow available from each ventilation shaft. The authors evaluated the technical and economic feasibility of two emerging systems that may …

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The General Characteristics Of Electromagnetic Radiation During Coal Fracture And Its Application In Outburst Prediction, Xue-Qiu He, En-Yuan Wang, Zhentang Liu Jun 1999

The General Characteristics Of Electromagnetic Radiation During Coal Fracture And Its Application In Outburst Prediction, Xue-Qiu He, En-Yuan Wang, Zhentang Liu

U.S. Mine Ventilation Symposium

Coal and methane outburst are catastrophic in coal mining, their prediction is difficult. In this paper, the electromagnetic radiation (EMR) generated during coal or rock deformation and fracturing is measured and analyzed. The results show that EMR truly exists during the fracture of coal or rock (with or without the presence of gas). It follows the Hurst statistical rule, and it basically exhibits gradually enhancing tendency during the process. The EMR strength and frequency are correlated to the coal or rock fracture process. Based on the experimental and theoretical studies, a new method for coal and methane outburst prediction is …

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Scale Tests, In-Situ Measurements And Simulation Of Methane Gas Distribution At Heading Faces, Shinsuke Nakayama, Masamoto Ichinose, Kenichi Uchino, Masahiro Inoue Jun 1999

Scale Tests, In-Situ Measurements And Simulation Of Methane Gas Distribution At Heading Faces, Shinsuke Nakayama, Masamoto Ichinose, Kenichi Uchino, Masahiro Inoue

U.S. Mine Ventilation Symposium

Distributions of methane gas concentration at a heading face with an auxiliary fan were measured in both an actual coal mine and a scale model. As a result, general distribution pattern of methane gas concentration was elucidated and it was found that there exist several areas where gas concentrations tend to rise to dangerous levels. A CFO (Computational Fluid Dynamics) method was also developed and the results of the computation were compared with those obtained in these measurements. It was concluded that the CFD can be used for simulating the distributions of gas concentration that are affected by conditions in …

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A New Laboratory Technique To Estimate Gas Diffusion Characteristics Of Coal, Satya Harpalani, Shaofan Ouyang Jun 1999

A New Laboratory Technique To Estimate Gas Diffusion Characteristics Of Coal, Satya Harpalani, Shaofan Ouyang

U.S. Mine Ventilation Symposium

This paper describes a new experimental technique developed to measure the diffusion coefficient (D) for a coal-methane system using the transient flow mechanism, and examine its dependency on factors that change with continued flow – pressure and gas concentration. Although developed primarily for coalbed methane reservoirs and coal in the gob regions, it also has application in situations where a second gas is injected in coal since it utilizes the principle of counter-diffusion. The results show that there is a continuous decrease in the value of D with decreasing mean concentration of methane in coal. The logarithm of D varies …

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Gob Well Flaring: Design And Impact Analysis, Daniel J. Brunner, Karl Schultz Jun 1999

Gob Well Flaring: Design And Impact Analysis, Daniel J. Brunner, Karl Schultz

U.S. Mine Ventilation Symposium

Currently, over 30 U.S. Coal Mining operations employ a system of degasification to assist in reducing the emission of methane into their mine ventilation systems. All of these mines use vertical gob wells. This is an effective gob de gasification technique for U.S. longwall coal mining operations, particularly when prime movers apply suction to the wellheads (active gas extraction). In most cases mine operators discharge gas recovered from gob wells directly to the atmosphere. This practice poses safety and environmental concerns, and wastes a potential resource. In the U.S. there are no standards for equipping actively extracted or passive gob …

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Economic Analysis Of Coalbed Methane Drainage Systems For Room-And-Pillar Operations, Yanbei Wang, Jan M. Mutmansky Jun 1999

Economic Analysis Of Coalbed Methane Drainage Systems For Room-And-Pillar Operations, Yanbei Wang, Jan M. Mutmansky

U.S. Mine Ventilation Symposium

The analysis of the economics of methane drainage operations in traditional room-and-pillar coal mining operations is the primary emphasis of this presentation. The paper analyzes the economic effects of ventilation costs versus drainage costs as a means of handling the methane in a hypothetical room-and-pillar operation. However, the effects of downtime savings due to methane reduction in the air stream and the impacts of marketing the methane are also studied. Comparisons are then made with the economics of drainage in longwall mining.

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Design Of Methane Drainage Systems To Reduce Mine Ventilation Requirements, Michael D. Zuber, Charles M. Boyer Ii, Denise L. Delozier Jun 1999

Design Of Methane Drainage Systems To Reduce Mine Ventilation Requirements, Michael D. Zuber, Charles M. Boyer Ii, Denise L. Delozier

U.S. Mine Ventilation Symposium

There are numerous proven methods to drain methane from coal seams in coal mines. These systems include vertical wells drilled ahead of mining, horizontal boreholes, gob wells, and others. However, these drainage systems are not typically applied properly to optimize gas recovery and minimize the cost of ventilation to the mine. This lack of optimization generally occurs due to the large up-front costs associated with the drainage systems and the lack of knowledge regarding the drainage technology. This results in the mine having a "reactive" response to methane drainage issues as opposed to a "pro-active" plan for handling methane drainage. …

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Methane Ignitions On Roof Bolters In Underground Coal Mines, John E. Urosek, William J. Francart Jun 1999

Methane Ignitions On Roof Bolters In Underground Coal Mines, John E. Urosek, William J. Francart

U.S. Mine Ventilation Symposium

Although not as frequent in nature as ignitions on continuous miner or longwall faces, ignitions of methane on roof bolters have caused serious injuries to underground coal miners. After reviewing the accident reports for all roof bolter ignitions from 1981 to 1998, a summary of the forty-one accidents has been developed. Of interest in the database is the ignition source, method of face ventilation, local velocity, methane liberation, size of the methane body ignited, and the duration of the flame. Three example ignitions are included.

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Evaluation Of A Continuous Miner Half-Curtain Dust Control System In A South African Underground Coal Mine, Bharath K. Belle, J. J. L. Du Plessis Jun 1999

Evaluation Of A Continuous Miner Half-Curtain Dust Control System In A South African Underground Coal Mine, Bharath K. Belle, J. J. L. Du Plessis

U.S. Mine Ventilation Symposium

The issues of public health and safety in the mining industry have been dealt with around the world through the intervention of governments. In 1997 the South African Department of Minerals and Energy (DME) sent out a directive to reduce the dust concentration level to /m3 at the operator's position for the sampling period. The reasons for the difficulty with compliance are: long headings up to 35m, inherently high dust generation rates of coal, and the increased use of highly mechanized equipment. A project was formulated under SIMRAC auspices with the title of "Underground Mechanical Miner Environmental Control" to …

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Effectiveness Of Cabs For Dust And Silica Control On Mobile Mining Equipment, Joseph J. Garcia, Ronald E. Gresh, Mary Beth Gareis, Robert A. Haney Jun 1999

Effectiveness Of Cabs For Dust And Silica Control On Mobile Mining Equipment, Joseph J. Garcia, Ronald E. Gresh, Mary Beth Gareis, Robert A. Haney

U.S. Mine Ventilation Symposium

The Mine Safety and Health Administration (MSHA) has conducted a study to evaluate the effectiveness of cabs for controlling silica dust exposure during operation of mobile mining equipment. This study focused on bulldozers, front -end loaders and haul trucks, was conducted at surface coal mining operations and underground metal and nonmetal mining operations. Each piece of equipment tested was equipped with a cab. The vehicles sampled were from a range of manufacturers having different types of filter media and air intake configurations. The purpose of this study was to determine the reduction of dust and silica exposure that could be …

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Niosh/Nci Study Of Exposure To Diesel Exhaust In Underground Mines — An Industry Perspective, Christopher J. Pritchard Jun 1999

Niosh/Nci Study Of Exposure To Diesel Exhaust In Underground Mines — An Industry Perspective, Christopher J. Pritchard

U.S. Mine Ventilation Symposium

In 1992, the National Institute For Occupational Safety and Health (NIOSH) initiated a study, funded by the National Cancer Institute (NCI), to evaluate the health effects, if any, involving underground miners exposure to diesel exhaust. An industry organization, the Methane Awareness Research Group (MARG) already in place to respond to gassy mine related issues, was redirected to work with diesel concerns. In 1995, NIOSH released a draft protocol and feasibility assessment, indicating its intent to initiate s study at 14 underground mines, some of which were operated by MARG members. After considerable debate on the study protocol, in-mine industrial hygiene …

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A Mathematical Model Of Heat Transfer In Partially Insulated Airways In Deep, Frozen Ground Placer Mines, Sukumar Bandopadhyay, Hanguang Wu, Michael G. Nelson Jun 1999

A Mathematical Model Of Heat Transfer In Partially Insulated Airways In Deep, Frozen Ground Placer Mines, Sukumar Bandopadhyay, Hanguang Wu, Michael G. Nelson

U.S. Mine Ventilation Symposium

Large seasonal variations in the temperature of the ventilating air in mines in the arctic cause changes in the original thermal field through heat and mass exchanges between the air and the surrounding medium. These thermal interactions have major influence on climatic quality as well as on the stability of the mine openings. Thawing of walls and roof in mine airways can be reduced by various types of thermal-insulation. Application of thermal-insulation prevents deep thawing of the rockmass surrounding an airway. In this case, the mechanism of heat transfer around a frozen, underground airway would be much different. A model …

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Table Of Contents, Multiple Authors Jun 1999

Table Of Contents, Multiple Authors

U.S. Mine Ventilation Symposium

No abstract provided.

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Buckling Mode Interaction In Cold-Formed Steel Columns And Beams, C. Jiang, Viorel Ungureanu, J. Michael Davies Oct 1998

Buckling Mode Interaction In Cold-Formed Steel Columns And Beams, C. Jiang, Viorel Ungureanu, J. Michael Davies

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

The buckling behaviour of cold-formed steel columns and beams is far from simple. The three generic forms of buckling, namely local buckling, distortional buckling and overall buckling, generally have different wavelengths and are usually restricted to different span ranges. However, there is also the possibility of interaction among these buckling modes at a certain span length. Thus, local plate buckling and distortional buckling may occur together with lateral-torsional buckling in such a way that they all have an influence on the ultimate load carrying capacity of a member. The influence of local buckling is taken into consideration in design codes …

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Spacing Of Connections In Compression Flanges Of Built-Up Cold-Formed Steel Beams, Roger A. Laboube, Wei-Wen Yu, Michael L. Jones Oct 1998

Spacing Of Connections In Compression Flanges Of Built-Up Cold-Formed Steel Beams, Roger A. Laboube, Wei-Wen Yu, Michael L. Jones

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

Built-up cold-formed steel sections may offer greater economy in building construction. Typical built-up sections are cellular decks or door and window header beams. A research project was initiated to determine if the current spacing criteria outlined in Section D1.2 of the AISI Specification accurately predicted the capacity of built-up sections with the cover plate in compression. This study showed that criteria No.2 of the AISI Design Specification spacing criteria is restrictive when applied to built-up cross sections in bending. All test sections continued to carry additional load after the cover plate buckled. The tests showed that as the spacing of …

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Bending Tests Of Hat Sections With Multiple Longitudinal Stiffeners, V. V. Acharya, R. M. Schuster Oct 1998

Bending Tests Of Hat Sections With Multiple Longitudinal Stiffeners, V. V. Acharya, R. M. Schuster

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

This paper is the first in a series of articles that report findings of the authors investigation into the behavior of cold formed steel hat sections in bending with multiple intermediate longitudinal stiffeners. Presented in this paper is the test program that was carried out at the University of Waterloo as part of a two year research program. It is known that sections with multiple intermediate stiffeners can fail either in a local sub-element buckling mode, or alternatively, can experience an overall plate buckling mode of failure. Although both failure modes were examined, the main objective was to develop a …

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Accelerated Test Development For Coil-Coated Steel Building Panels, K. M. Lawson, H. H. Lawson, H. E. G. Rommal, A. C. Tiburcio Oct 1998

Accelerated Test Development For Coil-Coated Steel Building Panels, K. M. Lawson, H. H. Lawson, H. E. G. Rommal, A. C. Tiburcio

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

This paper discusses the experimental design and the preliminary findings of an ongoing project designed to establish an accelerated laboratory test that would rank coating system performance the same as their performance in atmospheric exposure. A total of ten materials are included in the program: four substrates each with two coating systems and one substrate with two additional coating systems. Samples were installed at four atmospheric exposure sites: Middletown, OH, Daytona Beach, FL, Monroeville, PA, and Halifax, NS, Canada. Three different orientations were utilized at each of the exposure sites and a variety of building panel features were included on …

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