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Temperature distribution in a full-scale steel framed building subject to a natural fire
František Wald,Magdalena Chladná,David Moore,Aldina Santiago,Tom Lennon 국제구조공학회 2006 Steel and Composite Structures, An International J Vol.6 No.2
Current fire design codes for determining the temperature within the structural elements that form part of a complete building are based on isolated member tests subjected to the standard fire. However, the standard time-temperature response bears little relation to real fires and doesn’t include the effects of differing ventilation conditions or the influence of the thermal properties of compartment linings. The degree to which temperature uniformity is present in real compartments is not addressed and direct flame impingement may also have an influence, which is not considered. It is clear that the complex thermal environmental that occurs within a real building subject to a natural fire can only be addressed using realistic full-scale tests. To study global structural and thermal behaviour, a research project was conducted on the eight storey steel frame building at the Building Research Establishment’s Cardington laboratory. The fire compartment was 11 m long by 7 m wide. A fire load of 40 kg/m2 was applied together with 100% of the permanent actions and variable permanent actions and 56% of live actions. This paper summarises the experimental programme and presents the time-temperature development in the fire compartment and in the main supporting structural elements. Comparisons are also made between the test results and the temperatures predicted by the structural fire Eurocodes.
Design of corrugated sheets exposed to fire
Zden k Sokol,František Wald,Petra Kallerová 국제구조공학회 2008 Steel and Composite Structures, An International J Vol.8 No.3
This paper presents results of fire tests on corrugated sheets used as load bearing structure of roofs of industrial buildings. Additional tests of bolted sheet connections to the supporting structure at ambient and elevated temperatures are described. Three connection types were tested and their resistance, stiffness and deformation capacity was evaluated. Finite element simulations of the corrugated sheet based on the experimental observations are briefly described and design models are presented.
Effects of Cooling Rate on Precipitate Evolution and Residual Stresses in Al–Si–Mn–Mg Casting Alloy
Eunkyung Lee,Caitlin Walde,Brajendra Mishra 대한금속·재료학회 2018 METALS AND MATERIALS International Vol.24 No.4
The residual stresses with Different heat treatment conditions have been measured and correlated with the microstructuralbehavior of AA365. 30 and 100 K/min cooling of AA365 inhibited the transformation of precipitates under 773 K, respectively. The alloy cooled at 30 and 100 K/min exhibited tensile residual stresses of 6.2 and 5.4 MPa, respectively, while thealloy cooled at 1 and 10 K/min showed compressive stresses of − 12.8 and − 10.3 MPa, respectively. The formation β′, β″,and other intermetallic compounds aff ected the compressive residual stresses, and that the fracture of the brittle intermetallicphases could reduce the extent of residual stresses in the lattice through plastic deformation.
Temperature of Connections During Fire on Steel Framed Building
Jiří Chlouba,František Wald,Zdeněk Sokol 한국강구조학회 2009 International Journal of Steel Structures Vol.9 No.1
To study the global structural and thermal behaviour of buildings in fire, a research project was conducted including a fullscale test on a three storey steel frame building at Mittal Steel Ostrava before demolition. The main goal of the experiment was to verify the method for predicting joint temperatures and to improve it for the cooling phase. The fire compartment extending over a floor area of 24 m2 was built on the second floor. The fire load was 140 kg/m2 of wood and the ventilation was limited to an opening of 1,400×1,970 mm. This paper presents the time-temperature curves showing the development of the fire in the compartment and in the primary and secondary beams and its header plate connections. Comparisons are made between the test results and the temperatures predicted by the structural Eurocodes. The sensitivity of the connection behaviour to the estimated temperatures and associated degradation in material properties during the fire is demonstrated. To study the global structural and thermal behaviour of buildings in fire, a research project was conducted including a fullscale test on a three storey steel frame building at Mittal Steel Ostrava before demolition. The main goal of the experiment was to verify the method for predicting joint temperatures and to improve it for the cooling phase. The fire compartment extending over a floor area of 24 m2 was built on the second floor. The fire load was 140 kg/m2 of wood and the ventilation was limited to an opening of 1,400×1,970 mm. This paper presents the time-temperature curves showing the development of the fire in the compartment and in the primary and secondary beams and its header plate connections. Comparisons are made between the test results and the temperatures predicted by the structural Eurocodes. The sensitivity of the connection behaviour to the estimated temperatures and associated degradation in material properties during the fire is demonstrated.
Joseph Jeyaraj Joanna,Wald Navé,Harland Tony 서울대학교 교육연구소 2021 Asia Pacific Education Review Vol.22 No.3
Higher education institutions are seen as pivotal for fostering national economic growth in a globalised knowledge economy. Conducting research is an important aspect of that role, and there is pressure on institutions to increase their knowledge production, as well as to ofer advanced research degrees. This requires academics with doctoral level qualifcation who research in their feld. Research productivity is important for institutions because it contributes to prestige and better rankings in league tables, which result in more or better resources. This qualitative study examines the notion of ‘turning teachers into academics’ through the experiences of lecturers in a teaching-focused institution in Malaysia seeking university status. Becoming research active requires resources and a supportive environment that were largely unavailable, and so participants experienced an unhealthy intensifcation of their academic work and struggled to do research or complete their PhD qualifcations. The study showed that a successful transition required teachers to be genuinely motivated to do research and the institutions to provide adequate support. Under current circumstances of ferce competition between institutions and the inability to compromise teaching allocations, it is not clear how, or if, such a transition can happen without adversely afecting staf wellbeing.
Dejana Carić,Boris Rakvin,Marina Kveder,Katja Junker,Peter Walde,Edward Reijerse 한국물리학회 2015 Current Applied Physics Vol.15 No.11
Poly(PADPA) synthesized with the enzyme Trametes versicolor laccase (TvL) at pH = 3.5 in aqueous solution from the aniline dimer p-aminodiphenylamine (PADPA) was studied by EPR spectrometry at Xband and W-band frequencies. For the synthesis of poly(PADPA), vesicles formed from AOT (sodium bis- (2-ethylhexyl)sulfosuccinate) were used as structure-directing templates, and TvL/O2 as catalyst and oxidant. The isolated product is abbreviated as “poly(PADPA)-TvL-AOT” to distinguish it from poly(- PADPA) obtained by other means. The EPR spectrum of poly(PADPA)-TvL-AOT recorded at room temperature is complex. It can be decomposed into two separate Dysonetype spectral components. Furthermore, the spectra measured at high frequency exhibit a line broadening behavior in comparison to the spectra recorded at low frequency where there is no line broadening. This behavior was used to estimate the effective inter-chain spin exchange interaction for each monitored spectral component. The obtained effective distances between the polymer (or oligomer) chains in both identified components of poly(PADPA)-TvL-AOT can be explained by considering slightly different interactions between the chains and the AOT molecules present in the sample. Additionally, due to different average g tensor values, gav, of these components, it seems that each spectral component originates from one of two different molecular subunits (or local structural motifs) within the polymer (or oligomer) chains.