The Experts below are selected from a list of 2364 Experts worldwide ranked by ideXlab platform
Mahen Mahendran - One of the best experts on this subject based on the ideXlab platform.
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Full-scale fire resistance tests of steel and Plasterboard sheathed web-stiffened stud walls
Thin-walled Structures, 2019Co-Authors: Yomal Dias, Mahen Mahendran, Keerthan PoologanathanAbstract:Light gauge steel-framed (LSF) walls, commonly made with lipped channel studs and gypsum Plasterboard sheathing, are increasingly being used in low to mid-rise buildings. Improvements have been made with respect to fire, wind/seismic and energy performance of LSF walls with the use of improved stud sections, wall configurations, different sheathing members, and insulation materials. Although the provision of sheet steel as sheathing has been found to improve the in-plane shear capacity of LSF walls, its effects on the fire performance of load bearing walls remain unknown. Three full-scale ISO 834 standard fire tests were conducted in this study to investigate the fire performance of axially loaded gypsum Plasterboard and steel sheathed LSF walls made with web-stiffened studs. The results revealed that compared to the commonly used lipped channel stud, the web-stiffened stud is capable of withstanding a 57% greater axial compression load, yet yield the same fire resistance level (FRL), when sheathed only with two layers of gypsum Plasterboard. Under the selected load ratio, the addition of steel sheathing caused only marginal improvements in the stud temperature development, resulting in minor improvements to the FRL of load bearing walls. However, the axial load bearing capacity improvement caused by the inclusion of steel sheathing allowed the web-stiffened stud to withstand a 10% greater axial compression load compared to the Plasterboard only wall.
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axial compression strength of gypsum Plasterboard and steel sheathed web stiffened stud walls
Thin-walled Structures, 2019Co-Authors: Yomal Dias, Mahen Mahendran, Keerthan PoologanathanAbstract:Cold-formed steel-framed walls lined with appropriate sheathing materials are increasingly being used as vertical load bearing systems due to their many benefits. Despite this widespread use, attempts at improving their structural efficiency using either optimised studs or novel sheathing elements have been scarce. Arguably, the sustained use of lipped channel studs and conventional sheathing materials have long forestalled such improvements. Firstly, this study provides experimental evidence on the superior characteristics of the web-stiffened studs, developed specifically for load bearing steel-framed wall applications, and their ability to utilise sheathing restraints to achieve higher axial compression strengths. Secondly, it shows that the use of steel sheathing, either in isolation or together with gypsum Plasterboards, significantly increases the strength of the web-stiffened stud. Thirdly, single Plasterboard web-stiffened stud walls are found to be highly efficient due to the monolithic nature of the sheathing that leads to greater degrees of composite action between the studs and the sheathing. Finally, it presents a spring based analytical model capable of estimating the failure loads of sheathed web-stiffened studs conveniently. The model particularly focuses on the out-of-plane restraints provided by the sheathing, the contribution of which to the overall strength of the wall has traditionally been considered trivial, but is shown to be substantial in the case of web-stiffened studs. Using the improvements proposed, high capacity steel-framed load bearing walls can be developed with significant material and cost savings.
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fire performance of steel and Plasterboard sheathed non load bearing lsf walls
Fire Safety Journal, 2019Co-Authors: Yomal Dias, Poologanathan Keerthan, Mahen MahendranAbstract:Light gauge steel-framed (LSF) walls are used as load bearing and non-load bearing building components in traditional concrete framed buildings and emerging all-steel structures. Recent building fire disasters around the world have highlighted the necessity for improved fire performance in such building components. While the fire performance of gypsum Plasterboard, magnesium oxide board, calcium silicate board and oriented strand board (OSB) sheathed LSF walls has been assessed using fire tests and numerical analyses in the past, fire performance of steel sheathed walls remains unknown. Steel sheathing can improve the in-plane shear capacity of steel framed walls and is an accepted lateral load carrying system with widespread applications in the cold-formed steel construction industry. This paper presents the results of a series of small-scale fire tests conducted on steel and gypsum Plasterboard sheathed composite panels and framed walls, and also an enthalpy based analytical study using the experimental results. Provision of steel sheathing either only internally, only externally or both internally and externally in combination was found to enhance the fire performance of Plasterboard panels and Plasterboard framed walls. The confinement of water within Plasterboards for a prolonged duration with the provision of steel sheathing was found to be the prime cause of this improvement. Furthermore, the formation of thermal bridges across the stud in cavity insulated walls was found to reduce the fire performance significantly.
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fire tests of non load bearing light gauge steel frame walls lined with calcium silicate boards and gypsum Plasterboards
Institute for Future Environments; Science & Engineering Faculty, 2017Co-Authors: Anthony Deloge Ariyanayagam, Mahen MahendranAbstract:Highlights - Investigated the fire performance of calcium silicate board lined cold-formed steel stud walls. - No integrity failure was observed in the 20 mm thick calcium silicate board lining. - Fall-off and cracking of calcium silicate boards were not observed in the fire tests. - Insulation failure occurred in calcium silicate board lined non-load bearing walls. - Compared the fire performance of calcium silicate board lined walls with gypsum Plasterboard and magnesium oxide board lined walls. Abstract Light gauge Steel Frame (LSF) wall systems are made of cold-formed steel studs and tracks, and lined with wall lining materials. Conventionally, gypsum Plasterboards are used as wall lining material in LSF wall systems. The fire performance of LSF walls is mainly dependent on the type and configuration of wall lining material, which delays the heat transfer through the wall and protects the steel studs from being heated rapidly. Recently, calcium silicate board lining is increasingly used in LSF wall systems because of its improved physical and thermal properties while being lightweight, cost effective, impact and moisture resistant. However, their fire performance has not been investigated in detail. Hence two full scale fire tests were conducted on non-load bearing LSF walls lined with calcium silicate boards. For comparison purposes two fire tests were also conducted on conventional gypsum Plasterboard lined LSF walls. This paper presents the details of this experimental study on the fire performance of LSF walls and the results including fire resistance levels and time-temperature profiles across the wall panels. Effects of using calcium silicate board lining are discussed by comparing the fire test results of LSF wall lined with gypsum Plasterboards and previously conducted studies on magnesium oxide board lined LSF walls. The results showed that the fire performance of calcium silicate board lined walls was similar to that of conventional gypsum Plasterboard lined walls, but was superior to that of magnesium oxide board lined walls. The failure criterion of these calcium silicate board lined walls was found to be insulation as opposed to being the integrity failure observed in previous studies.
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detrimental effects of Plasterboard joints on the fire resistance of light gauge steel frame walls
Institute for Future Environments; Science & Engineering Faculty, 2016Co-Authors: Anthony Deloge Ariyanayagam, Sivakumar Kesawan, Mahen MahendranAbstract:Light gauge Steel Frame (LSF) walls are commonly used in building construction. In general, they are lined with single or double layers of gypsum Plasterboards with and without cavity insulation. Gypsum Plasterboards act as a thermal barrier to protect the thin-walled steel studs from rapid temperature rise. In these walls, Plasterboard joints are located along the studs for ease of construction and are protected by filler materials. During fires, these Plasterboard joints crack and open up, and thus allow the stud temperatures to rise rapidly and initiate premature structural failures in LSF walls. This research investigated the detrimental effects of these Plasterboards joints on the fire resistance rating of single and double Plasterboard lined walls based on the hot flange time-temperature profiles of studs from full scale fire tests. To overcome the detrimental effects of Plasterboard joints, the back-blocking technique was used, where Plasterboard joints were placed between studs with 150 mm wide Plasterboards as back-blocks. Full scale fire tests and numerical studies were performed on single Plasterboard lined load bearing LSF wall panels to investigate the improved fire performance by using this technique. They showed that the fire resistance rating of these LSF walls was increased by 25% in comparison to the conventional Plasterboard joint arrangement over the studs. This paper presents the details of this research on the detrimental effects of Plasterboard joints on the fire resistance of load bearing LSF walls, and the results. It also includes a discussion and results for non-load bearing LSF walls.
Mahendran Mahen - One of the best experts on this subject based on the ideXlab platform.
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Local in-plane strength and stiffness of stud-to-sheathing fastener connections in LSF wall panels
'Elsevier BV', 2021Co-Authors: Abeysiriwardena Tharindu, Peiris, Mithum Chamara Shan, Mahendran MahenAbstract:Light-gauge steel framed (LSF) wall systems of low- and mid-rise buildings are made of cold-formed steel studs and tracks and lined with sheathing material such as gypsum Plasterboard. The stiffness provided by sheathing can be idealised into three main components, namely, in-plane, out-of-plane and rotational stiffness. Idealised in-plane stiffness has been used commonly in the numerical and analytical studies of cold-formed steel stud walls. Experimental evidence shows that local in-plane response depends on several factors such as stud thickness, thickness of sheathing material, screw fastener diameter, fastener end and edge distances, number of layers of sheathing material and environmental conditions, of which the effects of most of them are not well understood. An experimental study was therefore conducted to investigate the non-linear local in-plane strength and stiffness of screw-fastened stud-to-gypsum Plasterboard sheathing connections by varying a range of parameters affecting their stiffness and capacities. The resulting load-displacement curves were analysed, and models of characteristic curves were developed. A finite element model and an analytical model were then developed to determine the local in-plane response and initial stiffness of stud-to-sheathing screw fastener connections, by employing pure bearing response of sheathing, and were validated using experimental results
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Elevated temperature thermal properties of advanced materials used in LSF systems
'Wiley', 2021Co-Authors: Gnanachelvam Sayilacksha, Mahendran Mahen, Ariyanayagam AnthonyAbstract:Lightweight cold-formed steel (CFS) construction solutions are increasingly adopted in low and mid-rise buildings. Many different materials are used to construct CFS wall systems, without a full understanding of their thermal properties. For many of these materials, only ambient temperature thermal properties are available from their manufacturers. This creates difficulty in classifying the materials for use at elevated temperatures. In this study, a series of elevated temperature thermal property tests to measure specific heat, thermal conductivity, and mass loss was conducted for a range building materials from wallboards, insulation, and phase-change materials (PCMs), used in Australia and several other countries. Simultaneous Thermal Analyser and Laser Flash Apparatus were used to determine the elevated temperature thermal properties of the selected materials, gypsum Plasterboard, PCM incorporated gypsum Plasterboard, magnesium sulphate board, fibre cement board, cellulose insulation, vacuum insulation panel, microencapsulated paraffin PCM, and bio-based PCM. Their elevated temperature thermal properties are presented in this article, which also includes analyses of their chemical composition and associated chemical reactions at elevated temperatures. These results can be used in the selection of suitable energy-efficient and fire-resistive materials, and in heat transfer modeling to identify wall configurations with increased fire resistance and energy efficiency
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Fire resistance of LSF wall systems lined with different wallboards including bio-PCM mat
'Elsevier BV', 2020Co-Authors: Gnanachelvam Sayilacksha, Ariyanayagam Anthony, Mahendran MahenAbstract:Light gauge steel framed (LSF) wall systems made of cold-formed steel studs and lined with different types of wallboards are increasingly used for various purposes. Gypsum Plasterboards are commonly used for fire protection purposes, while recently other types of wallboards are being used based on their improved thermal and physical performance but without an understanding of their fire resistance. To increase the thermal mass of LSF wall systems, phase change materials (PCMs) with high thermal storage capacity can be used, but since some organic PCMs increase the fuel load in fire, bio-based PCMs are preferred as they are less flammable than paraffin based PCMs. However, the fire resistance of LSF wall systems incorporated with bio-based PCM has not been investigated. Therefore, this research study investigated the thermal properties of selected wallboards first and then the fire resistance of non-load bearing LSF wall systems lined with different types of wallboards such as gypsum Plasterboard, magnesium sulphate board, vermiculux board and fibre cement board using standard fire tests including a thermal mass improved LSF wall system using bio-based PCM mat. Findings revealed that gypsum Plasterboard gives the highest fire resistance, whereas the fibre cement board gives the lowest. Importantly, the thermal mass improved LSF wall system did not exhibit any reduction to its fire resistance due to the use of bio-based PCM mat. This paper presents the details of the standard fire tests of LSF wall systems and the results
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Fire resistance behaviour of LSF floor-ceiling configurations
'Elsevier BV', 2020Co-Authors: Steau Edward, Mahendran MahenAbstract:Light gauge Steel Frame (LSF) floor-ceiling systems made of thin-walled cold-formed steel structural members deliver innovative, lightweight and cost effective solutions for many floor assemblies. However, the mechanical properties of cold-formed steel structural members deteriorate in fire. Hence fire rated gypsum Plasterboard ceilings are required to protect them and avoid premature failures of floor assemblies. However, the behaviour of LSF floor-ceiling systems in fire is not well understood. Hence a series of small-scale standard fire tests was undertaken to investigate the fire resistance of cold-formed LSF floor-ceiling systems of varying configurations. Configurations included structural plywood as the subfloor, gypsum Plasterboard ceilings, thin steel sheathing, different joist sections such as lipped channel beam and rivet fastened rectangular hollow flange channel beam and rockwool cavity insulation. The effects of these parameters on the fire resistance of LSF floor-ceiling assemblies are discussed in this paper. Fire resistance improvements of 21–32% were observed when steel sheathing was used in varying configurations. This shows the potential of using thin steel sheathing below the gypsum Plasterboard that enhanced the insulation failure times by resisting gypsum Plasterboard fall-off. However, cavity insulation led to reduced fire resistance times while plywood subfloors exhibited rapid decomposition and burning when the temperature exceeded 234°C. This paper presents the details of the small-scale standard fire tests of LSF floor-ceiling systems of varying configurations and the results in terms of time-temperature curves and fire resistance times
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Experimental study of fire resistant board configurations under standard fire conditions
'Elsevier BV', 2020Co-Authors: Steau Edward, Mahendran Mahen, Poologanathan KeerthanAbstract:Cold-formed Light gauge Steel Frame (LSF) floor-ceiling systems are commonly made with non-combustible fire protective membrane to protect the steel floor joists in fire. Thermal improvements to the fire protective membrane delay the heat transfer to structural elements and provide enhanced fire resistance level. Hence, this study addresses the thermal performance of different fire resistant board configurations under standard fire conditions to compare and propose improvements to conventional systems. Small-scale fire tests were conducted for a range of configurations of gypsum Plasterboard, calcium silicate board and magnesium oxide board with the inclusion of thin steel sheathing. Fire test results showed that gypsum Plasterboard and calcium silicate board performed very similar in regards to insulation criterion based failure times, while magnesium oxide board performed considerably worse. In all cases steel sheathing provided improved failure times. Improvements of 48%, 33% and 47% were obtained for gypsum Plasterboard, calcium silicate board and magnesium oxide board when steel sheathing was used. This paper presents the details of the small-scale fire tests of different fire resistant board configurations and the results of time-temperature profiles. Based on these results, optimum fire resistant board configurations are recommended to achieve higher fire resistance levels for LSF floor-ceiling systems
Prakash Kolarkar - One of the best experts on this subject based on the ideXlab platform.
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experimental study of load bearing cold formed steel wall systems under fire conditions
Thin-walled Structures, 2013Co-Authors: Shanmuganathan Gunalan, Prakash Kolarkar, Mahen MahendranAbstract:Light Gauge Steel Framing (LSF) walls made of cold-formed and thin-walled steel lipped channel studs with Plasterboard linings on both sides are commonly used in commercial, industrial and residential buildings. However, there is limited data about their structural and thermal performance under fire conditions while past research showed contradicting results about the benefits of using cavity insulation. A new composite wall panel was recently proposed to improve the fire resistance rating of LSF walls, where an insulation layer was used externally between the Plasterboards on both sides of the wall frame instead of using it in the cavity. In this research 11 full scale tests were conducted on conventional load bearing steel stud walls with and without cavity insulation, and the new composite panel system to study their thermal and structural performance under standard fire conditions. These tests showed that the use of cavity insulation led to inferior fire performance of walls, and provided supporting research data. They demonstrated that the use of insulation externally in a composite panel enhanced the thermal and structural performance of LSF walls and increased their fire resistance rating. This paper presents the details of the LSF wall tests and the thermal and structural performance data and fire resistance rating of load-bearing wall assemblies lined with varying Plasterboard-insulation configurations under two different load ratios. Fire test results including the time–temperature and deflection profiles are presented along with the failure times and modes.
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experimental studies of non load bearing steel wall systems under fire conditions
Fire Safety Journal, 2012Co-Authors: Prakash Kolarkar, Mahen MahendranAbstract:Fire safety of buildings has been recognised as very important by the building industry and the community at large. Traditionally, increased fire rating is provided by simply adding more Plasterboards to light gauge steel frame (LSF) walls, which is inefficient. Many research studies have been undertaken to investigate the thermal behaviour of traditional LSF stud wall systems under standard fire conditions. However, no research has been undertaken on the thermal behaviour of LSF stud walls using the recently proposed composite panel. Extensive fire testing of both non-load bearing and load bearing wall panels was conducted in this research based on the standard time-temperature curve in AS1530.4. Three groups of LSF wall specimens were tested with no insulation, cavity insulation and the new composite panel based on an external insulation layer between Plasterboards. This paper presents the details of this experimental study into the thermal performance of non-load bearing walls lined with various configurations of Plasterboard and insulation. Extensive descriptive and numerical results of the tested non-load bearing wall panels given in this paper provide a thorough understanding of their thermal behaviour, and valuable time-temperature data that can be used to validate numerical models. Test results showed that the innovative composite stud wall systems outperformed the traditional stud wall systems in terms of their thermal performance, giving a much higher fire rating.
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structural and thermal performance of cold formed steel stud wall systems under fire conditions
Faculty of Built Environment and Engineering, 2011Co-Authors: Prakash KolarkarAbstract:Cold-formed steel stud walls are a major component of Light Steel Framing (LSF) building systems used in commercial, industrial and residential buildings. In the conventional LSF stud wall systems, thin steel studs are protected from fire by placing one or two layers of Plasterboard on both sides with or without cavity insulation. However, there is very limited data about the structural and thermal performance of stud wall systems while past research showed contradicting results, for example, about the benefits of cavity insulation. This research was therefore conducted to improve the knowledge and understanding of the structural and thermal performance of cold-formed steel stud wall systems (both load bearing and non-load bearing) under fire conditions and to develop new improved stud wall systems including reliable and simple methods to predict their fire resistance rating. Full scale fire tests of cold-formed steel stud wall systems formed the basis of this research. This research proposed an innovative LSF stud wall system in which a composite panel made of two Plasterboards with insulation between them was used to improve the fire rating. Hence fire tests included both conventional steel stud walls with and without the use of cavity insulation and the new composite panel system. A propane fired gas furnace was specially designed and constructed first. The furnace was designed to deliver heat in accordance with the standard time temperature curve as proposed by AS 1530.4 (SA, 2005). A compression loading frame capable of loading the individual studs of a full scale steel stud wall system was also designed and built for the load-bearing tests. Fire tests included comprehensive time-temperature measurements across the thickness and along the length of all the specimens using K type thermocouples. They also included the measurements of load-deformation characteristics of stud walls until failure. The first phase of fire tests included 15 small scale fire tests of gypsum Plasterboards, and composite panels using different types of insulating material of varying thickness and density. Fire performance of single and multiple layers of gypsum Plasterboards was assessed including the effect of interfaces between adjacent Plasterboards on the thermal performance. Effects of insulations such as glass fibre, rock fibre and cellulose fibre were also determined while the tests provided important data relating to the temperature at which the fall off of external Plasterboards occurred. In the second phase, nine small scale non-load bearing wall specimens were tested to investigate the thermal performance of conventional and innovative steel stud wall systems. Effects of single and multiple layers of Plasterboards with and without vertical joints were investigated. The new composite panels were seen to offer greater thermal protection to the studs in comparison to the conventional panels. In the third phase of fire tests, nine full scale load bearing wall specimens were tested to study the thermal and structural performance of the load bearing wall assemblies. A full scale test was also conducted at ambient temperature. These tests showed that the use of cavity insulation led to inferior fire performance of walls, and provided good explanations and supporting research data to overcome the incorrect industry assumptions about cavity insulation. They demonstrated that the use of insulation externally in a composite panel enhanced the thermal and structural performance of stud walls and increased their fire resistance rating significantly. Hence this research recommends the use of the new composite panel system for cold-formed LSF walls. This research also included steady state tensile tests at ambient and elevated temperatures to address the lack of reliable mechanical properties for high grade cold-formed steels at elevated temperatures. Suitable predictive equations were developed for calculating the yield strength and elastic modulus at elevated temperatures. In summary, this research has developed comprehensive experimental thermal and structural performance data for both the conventional and the proposed non-load bearing and load bearing stud wall systems under fire conditions. Idealized hot flange temperature profiles have been developed for non-insulated, cavity insulated and externally insulated load bearing wall models along with suitable equations for predicting their failure times. A graphical method has also been proposed to predict the failure times (fire rating) of non-load bearing and load bearing walls under different load ratios. The results from this research are useful to both fire researchers and engineers working in this field. Most importantly, this research has significantly improved the knowledge and understanding of cold-formed LSF walls under fire conditions, and developed an innovative LSF wall system with increased fire rating. It has clearly demonstrated the detrimental effects of using cavity insulation, and has paved the way for Australian building industries to develop new wall panels with increased fire rating for commercial applications worldwide.
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thermal performance of Plasterboard lined steel stud walls
Recent research and developments in cold-formed steel design and construction, 2008Co-Authors: Prakash Kolarkar, Mahen MahendranAbstract:In response to the market demand for fire separations in the light industrial, commercial and residential buildings, a research project is currently under way to improve the thermal performance of cold-formed steel stud wall systems used in these buildings. Extensive fire testing of both non-load-bearing and load-bearing wall panels has been completed to date in the Fire Research Laboratory of Queensland University of Technology. This paper presents the details of this experimental study into the thermal performance of some small scale non-load-bearing walls lined with dual layers of Plasterboard and insulation. The first two wall panels were built traditionally using lipped channels with two Plasterboard linings on both sides and the cavity filled with and without glass fibre insulation. The third panel tested was built similarly, but with the insulation sandwiched between the Plasterboards on either side of the steel wall frame instead of being placed in the cavity. Fire tests undertaken were based on the standard time-temperature curve recommended by AS 1530.4 (SA, 2005). Experimental results showed that the new stud wall system outperformed the traditional stud wall system giving a much higher fire rating.
Nethercot D - One of the best experts on this subject based on the ideXlab platform.
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Experimental study of sheathed cold-formed steel beam-columns
'Elsevier BV', 2021Co-Authors: Kyprianou C, Kyvelou P, Gardner L, Nethercot DAbstract:An experimental study of sheathed cold-formed steel C-lipped wall studs, with service holes, subjected to compression and major axis bending is presented in this paper. A total of 17 experiments were performed with both oriented strand board (OSB) and Plasterboard used as sheathing and with varying connector spacing employed between the sheathing panels and the steel members. The tested specimens comprised a single 2.4 m long column sheathed on both sides and secured at the ends to top and bottom tracks. The member tests were complemented by material tests, stub column tests and initial geometric imperfection measurements. The specimens were tested in a dual-actuator rig where axial compression was applied by means of a vertical actuator through the top track, while bending was applied through the application of four lateral point loads. Eight pure compression tests with both Plasterboard and OSB sheathing and with the spacing of the connectors varying between 75 mm and 600 mm were initially performed. Specimens with OSB sheathing were then tested under pure bending and combined loading. The full load–deformation responses and failure modes of the member test specimens are reported. The compressed studs connected to the Plasterboard sheathing at wider spacings exhibited pull-through failure of the connectors, followed by flexural torsional buckling, while the specimens with denser connector spacings, failed by local buckling at the member ends. The OSB sheathed specimens under pure compression failed by local and distortional buckling, those under combined loading exhibited local failure at the service openings, while for those under pure bending, local buckling and stud-to-track connector failure occurred. Reducing the spacing of the connectors from 600 mm to 75 mm resulted in up to 20% and 30% increases in capacity for the studs sheathed with OSB and Plasterboard respectively
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Characterisation of material and connection behaviour in sheathed cold-formed steel wall systems - Part 1: experimentation and data compilation
'Wiley', 2020Co-Authors: Kyprianou C, Kyvelou P, Gardner L, Nethercot DAbstract:The material and connection behaviour in sheathed cold-formed steel wall systems are investigated in the present paper through experimentation. A total of 103 material and component tests was performed, including six cold-formed steel tensile coupon tests, nine tests on screws in tension, nine tests on screws in shear, 36 material tests on Plasterboard and orientated strand board (OSB), 25 pull-through connection tests and 18 push-out (shear) connection tests. The Plasterboard and oriented strand board were tested in both compression and tension, as well as both longitudinally and transversely to the production direction of the board. The main objective of the study was to measure and characterise the nonlinear response of all the materials and sheathing-to-steel connection components that are used in typical cold-formed steel wall systems, to support the ongoing and future development of accurate numerical simulations and structural design provisions for such systems. The present paper focuses on the experimental investigation and the collection of existing test data from the literature; a description of all the tests performed and a discussion of the results obtained are provided. The companion paper focuses on the establishment and assessment of predictive models to describe the responses of the material and connection components
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Characterisation of material and connection behaviour in sheathed cold-formed steel wall systems - Part 2: analytical modelling
'Elsevier BV', 2020Co-Authors: Kyprianou C, Kyvelou P, Gardner L, Nethercot DAbstract:Analytical models to describe the material and connection behaviour of the key components of sheathed cold-formed steel wall systems are developed and assessed in the present paper. The experimental data generated and collected in the companion paper (Kyprianou et al. [1]) are utilised for the calibration of the developed models. The assembled experimental database comprises the results of more than 400 physical tests, featuring material tests on Plasterboard and oriented strand board (OSB), screw connector tests as well such as pull-through and push-out tests. The Ramberg–Osgood model (Ramberg and Osgood [2]) was shown to accurately describe the stress–strain behaviour of both Plasterboard and OSB in the longitudinal and transverse direction in both tension and compression, while the Mander model (Mander et al. [3]) was also shown to accurately capture the compression behaviour for both materials and to follow the post peak unloading response. A generalised Ramberg–Osgood curve with linear post-peak unloading was adopted for describing the pull-through load-deformation behaviour of screws in OSB and Plasterboard, while a similar generalised Ramberg–Osgood formulation, but with different exponents for the initial and subsequent parts of the curve was shown to accurately capture the shear load-slip behaviour of screws in steel-to-board connections. Predictive expressions for the ultimate capacities and recommended values for the remaining model parameters are provided herein. The developed predictive models are suitable for use in numerical simulations and advanced design methods
Yomal Dias - One of the best experts on this subject based on the ideXlab platform.
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Full-scale fire resistance tests of steel and Plasterboard sheathed web-stiffened stud walls
Thin-walled Structures, 2019Co-Authors: Yomal Dias, Mahen Mahendran, Keerthan PoologanathanAbstract:Light gauge steel-framed (LSF) walls, commonly made with lipped channel studs and gypsum Plasterboard sheathing, are increasingly being used in low to mid-rise buildings. Improvements have been made with respect to fire, wind/seismic and energy performance of LSF walls with the use of improved stud sections, wall configurations, different sheathing members, and insulation materials. Although the provision of sheet steel as sheathing has been found to improve the in-plane shear capacity of LSF walls, its effects on the fire performance of load bearing walls remain unknown. Three full-scale ISO 834 standard fire tests were conducted in this study to investigate the fire performance of axially loaded gypsum Plasterboard and steel sheathed LSF walls made with web-stiffened studs. The results revealed that compared to the commonly used lipped channel stud, the web-stiffened stud is capable of withstanding a 57% greater axial compression load, yet yield the same fire resistance level (FRL), when sheathed only with two layers of gypsum Plasterboard. Under the selected load ratio, the addition of steel sheathing caused only marginal improvements in the stud temperature development, resulting in minor improvements to the FRL of load bearing walls. However, the axial load bearing capacity improvement caused by the inclusion of steel sheathing allowed the web-stiffened stud to withstand a 10% greater axial compression load compared to the Plasterboard only wall.
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fire performance of steel and Plasterboard sheathed non load bearing lsf walls
Fire Safety Journal, 2019Co-Authors: Yomal Dias, Poologanathan Keerthan, Mahen MahendranAbstract:Light gauge steel-framed (LSF) walls are used as load bearing and non-load bearing building components in traditional concrete framed buildings and emerging all-steel structures. Recent building fire disasters around the world have highlighted the necessity for improved fire performance in such building components. While the fire performance of gypsum Plasterboard, magnesium oxide board, calcium silicate board and oriented strand board (OSB) sheathed LSF walls has been assessed using fire tests and numerical analyses in the past, fire performance of steel sheathed walls remains unknown. Steel sheathing can improve the in-plane shear capacity of steel framed walls and is an accepted lateral load carrying system with widespread applications in the cold-formed steel construction industry. This paper presents the results of a series of small-scale fire tests conducted on steel and gypsum Plasterboard sheathed composite panels and framed walls, and also an enthalpy based analytical study using the experimental results. Provision of steel sheathing either only internally, only externally or both internally and externally in combination was found to enhance the fire performance of Plasterboard panels and Plasterboard framed walls. The confinement of water within Plasterboards for a prolonged duration with the provision of steel sheathing was found to be the prime cause of this improvement. Furthermore, the formation of thermal bridges across the stud in cavity insulated walls was found to reduce the fire performance significantly.
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axial compression strength of gypsum Plasterboard and steel sheathed web stiffened stud walls
Thin-walled Structures, 2019Co-Authors: Yomal Dias, Mahen Mahendran, Keerthan PoologanathanAbstract:Cold-formed steel-framed walls lined with appropriate sheathing materials are increasingly being used as vertical load bearing systems due to their many benefits. Despite this widespread use, attempts at improving their structural efficiency using either optimised studs or novel sheathing elements have been scarce. Arguably, the sustained use of lipped channel studs and conventional sheathing materials have long forestalled such improvements. Firstly, this study provides experimental evidence on the superior characteristics of the web-stiffened studs, developed specifically for load bearing steel-framed wall applications, and their ability to utilise sheathing restraints to achieve higher axial compression strengths. Secondly, it shows that the use of steel sheathing, either in isolation or together with gypsum Plasterboards, significantly increases the strength of the web-stiffened stud. Thirdly, single Plasterboard web-stiffened stud walls are found to be highly efficient due to the monolithic nature of the sheathing that leads to greater degrees of composite action between the studs and the sheathing. Finally, it presents a spring based analytical model capable of estimating the failure loads of sheathed web-stiffened studs conveniently. The model particularly focuses on the out-of-plane restraints provided by the sheathing, the contribution of which to the overall strength of the wall has traditionally been considered trivial, but is shown to be substantial in the case of web-stiffened studs. Using the improvements proposed, high capacity steel-framed load bearing walls can be developed with significant material and cost savings.
