scholarly journals Unbalanced snow distributions for the design of arch-shaped roofs in Canada

1980 ◽  
Vol 7 (4) ◽  
pp. 651-656 ◽  
Author(s):  
D. A. Taylor ◽  
W. R. Schriever
Keyword(s):  
Building Code ◽  
Large Radius ◽  
Design Loads ◽  
Snow Loads

This note examines in some detail the design snow loads on simple arches and curved roofs recommended in the 1977 Commentary on Snow Loads of the National Building Code of Canada. Empirical modifications that give more appropriate unbalanced snow loads for large-radius arches and that will alleviate the problems caused by some overconservative aspects of the 1977 design loads are presented. They have been accepted for inclusion in the 1980 commentary.

scholarly journals Snow loads for the design of cylindrical curved roofs in Canada, 1953–1980

1981 ◽  
Vol 8 (1) ◽  
pp. 63-76 ◽  
Author(s):  
D. A. Taylor
Keyword(s):  
Building Code ◽  
Design Loads ◽  
Snow Loads

Since 1975 recommended design loads on cylindrical curved roofs in the Commentaries on Snow Loads in National Building Code documents have undergone significant changes. This paper presents data and some of the background to the changes, and discusses the problems that have arisen with the recommendations published in the 1977 Commentary. The intent is to make recommended design snow distributions and loads as realistic as possible without undue complication. Further improvements are suggested.

Roof snow loads in Canada

1980 ◽  
Vol 7 (1) ◽  
pp. 1-18 ◽  
Author(s):  
D. A. Taylor
Keyword(s):  
Building Code ◽  
Detailed Design ◽  
Design Information ◽  
Snow Loads

The National Building Code of Canada requires buildings to be designed to carry uniformly and nonuniformly distributed snow loads and the "Commentary on Snow Loads" in Supplement No. 4 to the National Building Code of Canada gives detailed design information. This paper discusses the material given in the 1977 commentary and supplements it with examples and photographs.

Seismic Risk and Design Loads

2006 ◽  
Vol 22 (1) ◽  
pp. 115-128 ◽  
Author(s):  
Praveen K. Malhotra
Keyword(s):  
United States ◽  
Seismic Design ◽  
Seismic Risk ◽  
Western United States ◽  
Building Code ◽  
Design Procedures ◽  
Central United States ◽  
Design Loads

The 2003 International Building Code seismic design procedures do not result in uniform risk throughout the country. A comparison is made between the expected lifetime damage to two identical buildings—one in the western United States and other in the central United States. The seismic design accelerations are the same for these buildings, but the expected lifetime damage is very different. The causes of this difference are discussed in the paper.

Dynamic analysis of an unsymmetrical high rise building

1976 ◽  
Vol 3 (1) ◽  
pp. 107-118
Author(s):  
W. K. Tso ◽  
R. Bergmann
Keyword(s):  
Dynamic Analysis ◽  
Dynamic Modelling ◽  
Time History ◽  
Seismic Loading ◽  
Building Code ◽  
High Rise ◽  
Response Dynamic ◽  
Design Loads ◽  
Time History Response ◽  
Proper Perspective

A complete time history response dynamic analysis is carried out to establish the design seismic loading for the Harbour Centre building in Vancouver. The building has an elevated observation deck and restaurant offset from the centre of the structure. The paper describes the steps and considerations involved in the dynamic analysis such as the dynamic modelling of the structure, the choice of input ground records and the interpretation of the computed results. Whenever possible, the calculated values are compared with the 1975 National Building Code of Canada requirements to provide a proper perspective of the various approaches in establishing design loads for this building.

Span Rating of Solid-Sawn Deck Boards

2021 ◽  
Vol 71 (2) ◽  
pp. 171-176
Author(s):  
Madison A. Broers ◽  
Donald A. Bender
Keyword(s):  
North America ◽  
Dynamic Load ◽  
Building Code ◽  
Standard Committee ◽  
Minimum Requirements ◽  
Design Loads ◽  
Policy Testing ◽  
Technical Basis

Abstract Deck boards are key components in outdoor decks and balconies. The deck board market is shared primarily between solid-sawn and composite products. The focus of this article is solid-sawn wood deck boards, which are manufactured in North America as span-rated products following a policy promulgated by the American Lumber Standard Committee (ALSC). The latest revision of the ALSC span rating policy was approved in November 2020, and this article describes the technical basis for the changes. Distributed and concentrated design loads specified in the policy exceed building code minimum requirements. In addition, dynamic load amplification due to deck occupants is included in the new policy. Testing was performed to characterize the effects of partial fixity at joist supports caused by screw fasteners and was incorporated into the span rating methodology.

Load factor calibration for the proposed 2005 edition of the National Building Code of Canada: Statistics of loads and load effects

2003 ◽  
Vol 30 (2) ◽  
pp. 429-439 ◽  
Author(s):  
F M Bartlett ◽  
H P Hong ◽  
W Zhou
Keyword(s):  
Companion Paper ◽  
Reduction Factor ◽  
Building Code ◽  
Wind Loads ◽  
Load Factor ◽  
Live Load ◽  
Dead Load ◽  
Wind Speeds ◽  
Code Calibration ◽  
Snow Loads

The 2005 edition of the National Building Code of Canada (NBCC) will adopt a companion-action format for load combinations and specify wind and snow loads based on their 50 year return period values. This paper summarizes statistics for dead load, live load due to use and occupancy, snow load, and wind load that have been adopted for calibration, and a companion paper presents the calibration itself. A new survey of typical construction tolerances indicates that statistics for dead load widely adopted for building code calibration are adequate unless the dead load is dominated by thin, cast-in-place concrete toppings. Unique statistics for live load due to use and occupancy are derived that pertain specifically to the live load reduction factor equation used in the NBCC. Statistics for snow and wind loads are normalized using the 50 year values that will be specified in the 2005 NBCC. New statistics are determined for the factors that transform wind speeds and ground snow depths into wind and snow loads on structures.Key words: buildings, code calibration, companion action, dead loads, live loads, load combinations, load factors, reliability, safety, snow loads, wind loads.

Revised ground snow loads for the 1990 National Building Code of Canada

1989 ◽  
Vol 16 (3) ◽  
pp. 267-278 ◽  
Author(s):  
M. J. Newark ◽  
L. E. Welsh ◽  
R. J. Morris ◽  
W. V. Dnes
Keyword(s):  
Method Of Moments ◽  
Snow Depth ◽  
Extreme Value Distribution ◽  
Building Code ◽  
Snow Pack ◽  
Snow Density ◽  
Snow Load ◽  
The Mean ◽  
Snow Loads ◽  
Made In

The last systematic recalculation of ground snow loads in the Supplement to the National Building Code of Canada was made in 1977 and used data up to 1975. Data from three times as many stations are now available and there is also an additional 10 years of record. Using this expanded data base, ground snow loads have been recalculated for the 1990 Supplement.Several changes in methods have been utilized, the most significant of which is the use of an objective technique to estimate ground snow loads at Code (or other) locations. It explicitly incorporates an assumed dependence of the snow load on topographical elevation, and accounts for the magnitude of errors at snow depth observation sites. Other differences include (a) the use of the method of moments to fit the Gumbel extreme value distribution for the purpose of estimating the 30-year return period snow depth; (b) the use of geographically varying snow pack densities; and (c) using probabilistic rain components of the total snow load and estimating this component by use of a snow pack model.Results show an average national decrease of 6.6% in the 1990 loads compared with those in the 1985 Supplement. A regional exception is in the Northwest Territories where the use of a greater snow density has led to an average increase of about 16% in the loads. A reduction in the standard deviation about the mean load suggests a more spatially consistent set of values for the 1990 Supplement. Key words: snow, loads, building, code.

scholarly journals A survey of snow loads on the roofs of arena-type buildings in Canada

1979 ◽  
Vol 6 (1) ◽  
pp. 85-96 ◽  
Author(s):  
D. A. Taylor
Keyword(s):  
Pilot Study ◽  
Building Code ◽  
Case Histories ◽  
Annual Survey ◽  
Snow Loads ◽  
Unbalanced Loads

The paper presents data on snow loads on three shapes of arena-type structures in Canada: the cylindrical arch, and the gable and Hipel roofs. Since there has never been a regular annual survey of snow on arenas, the data were compiled from a 4 year pilot study of snow on Quonset-type buildings, from case histories, and from newspaper clippings.The data indicate that the maxima of the loads recommended for design in Commentary H on snow loads published in Supplement No. 4 to the National Building Code of Canada 1977 can be exceeded.Further, it appears from the data that three loading cases should be considered in the design of curved roofs: uniformly distributed, unbalanced, and symmetrical loads. It is apparent also that the unbalanced loads recommended for gable roofs may be too conservative.

Load factor calibration for the proposed 2005 edition of the National Building Code of Canada: Companion-action load combinations

2003 ◽  
Vol 30 (2) ◽  
pp. 440-448 ◽  
Author(s):  
F M Bartlett ◽  
H P Hong ◽  
W Zhou
Keyword(s):  
Companion Paper ◽  
Building Code ◽  
Wind Loads ◽  
Load Factor ◽  
Live Load ◽  
Dead Load ◽  
Limit States ◽  
Snow Load ◽  
Load Factors ◽  
Snow Loads

The 2005 edition of the National Building Code of Canada (NBCC) will adopt a companion-action format for load combinations and specify wind and snow loads based on their 50 year return period values. This paper presents the calibration of these factors, based on statistics for dead load, live load due to use and occupancy, snow load, and wind load, which are summarized in a companion paper. A target reliability index of approximately 3 for a design life of 50 years was adopted for consistency with the 1995 NBCC. The load combinations and load factors for strength and stability checks recommended for the 2005 NBCC were based on preliminary values from reliability analysis that were subsequently revised slightly to address major inconsistencies with past practice. The recommended load combinations and factors generally give factored load effects similar to those in the 1995 NBCC, but are up to 10% more severe for the combination of dead load plus snow load and are generally less severe for the combination of dead load, snow load, and live load due to use and occupancy. Load factors less than one are recommended for checking serviceability limit states involving specified snow and wind loads. Importance factors for various classifications of structure are also presented. Revisions to the commentaries of the NBCC are recommended that will provide guidance on dead load allowances for architectural and mechanical superimposed dead loads and cast-in-place cover slabs and toppings.Key words: buildings, code calibration, companion action, dead loads, live loads, load combinations, load factors, reliability, safety, snow loads, wind loads.

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