Search

The roof snow load in the National Building Code of Canada (NBCC) is expressed as the sum of the snow and rain components. A probabilistic analysis of the components was carried out by using the recorded historical meteorological data. Probabilistic characterizations of the annual maximum ground snow depth SA, ground snow load SL, and snowpack bulk density were given. By considering the commonly adopted probabilistic models for SA, it was found that the use of the lognormal distribution, Gumbel distribution, and generalized extreme value distribution (GEVD) for SA is preferred for 46%, 35%, and 19% of the considered meteorological stations. A similar observation was made for SL. Snow hazard maps in terms of return period values of SA and SL were developed. Also, the hazard maps of (winter) rain load, SR, were developed. It was found that the correlation coefficient between SA and SR is negligible; the implication of this is discussed. [ABSTRACT FROM AUTHOR]

• Updated probabilistic models for the annual maximum wind speed and the ground snow load depth for Canada. • Treated thunderstorm and non-thunderstorm winds in reliability analysis separately. • Calibrated new design wind and snow load and load combination factors for Canadian practice. • Calibrated and recommended load scaling factors accounting for climate change effects for the National Building Code of Canada. In the present study, an updating of the probabilistic models used for calibrating the wind load, snow load and companion load factors for the National Building Code of Canada (NBCC) are presented. The update of probabilistic models for the extreme wind speed and ground snow depth is based on historical climatological data over Canadian sites. For the updating of the statistics of the extreme wind speed, the effect of mixed wind climate (i.e., thunderstorm winds and non-thunderstorm winds) is considered. Reliability analysis is carried out based on this update by considering different load combinations. The results indicate that, for an improved reliability consistency, the use of a high return period to specify the environmental loads and with a unit load factor is preferable to the use of 50 year return period and a load factor greater than one for structural design code making, if the coefficient of variation of the extreme climatological elements is spatially varying. Most importantly, based on these findings and the results from the climate change modelling results, sets of load scaling factors accounting for climate change effects are calibrated for different regions in Canada. Both the use of the target reliability index for a 50-year design working life as well as of the target minimum required annual reliability index within each of the 50-year design working life are considered for the reliability-based calibration. Specific recommendations on the load and companion load factors are suggested for a future edition of NBCC. [ABSTRACT FROM AUTHOR]

The article offers the author's reply concerning the discussion on his article "Web bearing resistance of W-shape beams framing columns." It is pointed out that the study was an investigation of the effect of column cap plates on Web bearing resistance of W-shape beams framing in conjunction with a critical evaluation of the design equations suggested by the current Canadian steel design standard. The author expresses his gratitude towards the observations provided by the discusser for it adds forum for the further clarification of the methodology used to achieve the objectives of the study.

• Developed model for tornado occurrence rate for Canada based on the generalized linear model. • Identified preferred stochastic tornado occurrence model based on the database and covariates. • Developed the Canadian tornado hazard map in terms of the wind speed at 10 m height above the ground. • Proposed a simple equivalent tornado design wind profile which is the first of its kind. Tornadoes cause property damage and fatalities. A systematic assessment of tornado wind velocity hazard is presented in the present study for Canada based on reported historical tornado catalogue. For the assessment, the Poisson model, zero-inflated Poisson model, and negative binomial model, as well as the adaptive Gaussian kernel smoothing technique, are used to model tornado occurrence. The modeling takes into account the tornado reporting bias due to population density and uses the cloud-to-ground lightning flash density and the thunderstorm days as the explanatory variables. Statistical analysis results indicate that the negative binomial model is preferable. The tornado wind velocity hazard maps for Canada, in terms of wind velocity at 10 m height above the ground surface and return period T , V T (10), are developed based on an available probabilistic tornado wind field model. Also, a simple equivalent tornado design wind profile is developed based on the return period value of tornado wind speed at different heights. The developed tornado design wind profile only depends on V T (10), which greatly facilitates its potential use for structural design subjected to tornado wind load and its possible implementation in structural design code and standards. [ABSTRACT FROM AUTHOR]