Effects of roof size, heat transfer, and climate on snow loads: studies for the 1995 NBC

Irwin, Peter; Gamble, Scott; Taylor, D.A.

doi:10.1139/l95-087

Cited by 30 publications

(4 citation statements)

References 7 publications

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“…The FAE method has been used to determine design snow loads on over 70 roofs in North America, South America, Asia and Europe, and was also used in previous research, (Irwin, Gamble, and Taylor, 1995), funded by the National Research Council of Canada to develop improved snow load provisions for large flat roofs, which were incorporated into the 1995 edition of the NBCC. Due to space limitations, a more detailed description of the FAE method has not been included, but has been discussed in previous papers, (Irwin and Williams 1983); (Irwin and Gamble 1987); (Irwin and Gamble 1988); (Gamble, Kochanski and Irwin 1992); (Irwin, Gamble, Retzlaff and Taylor 1992); and (Irwin, Gamble, Hunter and Kochanski 1993).…”

Section: Test Methodologymentioning

confidence: 99%

Parametric Studies of Unbalanced Snow Loads on Arched Roofs

Hochstenbach¹,

Irwin²,

Gamble³

2004

Structures 2004

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Building codes and standards often indicate that unbalanced loading of arched roofs need not be considered if the roof is flat enough. They typically provide a threshold value for arch height as the criterion. However, real snow doesn't behave differently slightly above the threshold than slightly below. Recent building collapses have brought this issue into discussion since buildings designed below the threshold still produced significant unbalanced loads. The purpose of this research project was to investigate the lower bound of arched roof geometry and to compare the results with provisions of the 1995 National Building Code of Canada (NBCC) and the American Society of Civil Engineers Standard (ASCE 7-2002). Parametric Finite Area Element (FAE) snow loading simulations (using methodology described by Irwin, Gamble and Taylor, 1995) were performed on a range of arched roof geometries using a range of meteorological data sets. The results indicated that, in certain situations, significant unbalanced loading could be expected for roofs that would otherwise be treated as flat, warranting special consideration in the appropriate codes and standards. The study also indicated that the azimuthal orientation of the roof relative to the prevailing winds plays a major role in some cases.

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Section: Test Methodologymentioning

confidence: 99%

Parametric Studies of Unbalanced Snow Loads on Arched Roofs

Hochstenbach¹,

Irwin²,

Gamble³

2004

Structures 2004

Self Cite

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“…Before prototyping the proposed concept, it is important to understand the loading implications associated with adding an additional roof assembly, in addition to regional changes in snow loading from a building's original year of construction to that at the time of roof replacement. Many studies have focussed on roof loading and highlight the importance of understanding changes associated with building design, site anomalies, and weather trends (Stathopoulos, Luchian 1990;Taylor 1992;Irwin et al 1995;Kennedy et al 1985).…”

Section: Literature Reviewmentioning

confidence: 99%

Structural and Durability Analysis of a Novel Re-Roofing Concept

Richman

Bentz

Jermyn

et al. 2017

Engineering Structures and Technologies

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Metal roof decks in long-span light steel structures can become damaged and obsolete by corrosion should the roofing system become compromised. Re-roofing is conducted by either removing and replacing damaged areas (resulting in suspension of interior operations and lost revenue) or installing new decking directly over the damaged areas which can transfer corrosion to the new deck. This research conducts structural and durability analyses on a novel proposed re-roofing concept that installs a new metal roof deck over the existing deck by using a proprietary deck strap resulting in no interruption of interior processes. Preliminary structural analysis shows the proposed concept to be applicable to generic conditions around Southern Ontario. Recommendations for project specific structural analysis are made. Durability analysis demonstrates that the proposed concept system improves hygrothermal performance of the roof assembly in all cases except when insulation in the existing roof assembly is saturated. Saturated insulation should be removed prior to installing the re-roofing system.

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“…In snowy and windy regions, wind-induced snow drifting can cause many problems, such as unbalanced snow loads on roofs (e.g. Irwin et al, 1995;O'Rourke et al, 2005;Thiis and O'Rourke, 2015), snowdrift around buildings (e.g. Zallen, 1988;Thiis and Gjessing, 1999), low visibility (e.g.…”

Section: Introductionmentioning

confidence: 99%

CFD simulation of snow transport over flat, uniformly rough, open terrain: Impact of physical and computational parameters

Kang

Zhou

Hooff

et al. 2018

Journal of Wind Engineering and Industrial Aerodynamics

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In the past, Computational fluid dynamics (CFD) simulations have been successfully applied for the prediction of snow drift around buildings and on building roofs. A literature study indicates that a wide range of influential computational and physical parameters exist for snow drifting predictions in CFD, while the impact of these parameters is unclear, resulting in a lack of available CFD simulation guidelines. Therefore, this study presents a systematic and generic analysis with emphasis on the fundamentals of snow transport prediction techniques. Snow transport over flat, uniformly rough, open terrain, including snow saltation and snow suspension is successfully simulated using CFD and the results are compared to field measurements of snow concentrations for validation. This paper investigates the impact of grid resolution, falling velocity of snow, turbulent Schmidt number, threshold friction velocity of snow and turbulence model on the CFD simulation results. The results show that the falling velocity and the turbulent Schmidt number have largest impact. A slight change in the falling velocity or the turbulent Schmidt number significantly impacts the predicted snow concentration in the air. In addition, the turbulence model mainly affect the turbulent kinetic energy, another key factor that influences the numerical predictions of snow transport.

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Effects of roof size, heat transfer, and climate on snow loads: studies for the 1995 NBC

Cited by 30 publications

References 7 publications

Parametric Studies of Unbalanced Snow Loads on Arched Roofs

Parametric Studies of Unbalanced Snow Loads on Arched Roofs

Structural and Durability Analysis of a Novel Re-Roofing Concept

CFD simulation of snow transport over flat, uniformly rough, open terrain: Impact of physical and computational parameters

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