Question about National Building Code of Canada snow loads
Question about National Building Code of Canada snow loads
(OP)
Hello everyone,
I am reading the NBCC2015 on Clause 4.1.6.3 "Full and Partial Loading". I am not quite clear what the "partial loading" is, and how to apply it. To my understanding, it is a type of uniform loads other than nonuniformly distributed load. But the code says "flat roofs and shed roofs, gable roofs of 15° or less, and arch or curved roofs shall be designed for the specified uniform snow load...,...distributed on any one portion of the loaded area and half of this load on the remainder of the loaded area, in such a way as to produce the most critical effects on the member concerned." My questions are:
1). Does this mean there are three types of snow loads, uniformly load in the forms of both fully and partial loadings, and nonuniform load?
2). How to apply the partial load to "one portion" of the area? I mean, how to determine which area to apply the full and which area for the other half?
Thanks a lot,
Fiona
I am reading the NBCC2015 on Clause 4.1.6.3 "Full and Partial Loading". I am not quite clear what the "partial loading" is, and how to apply it. To my understanding, it is a type of uniform loads other than nonuniformly distributed load. But the code says "flat roofs and shed roofs, gable roofs of 15° or less, and arch or curved roofs shall be designed for the specified uniform snow load...,...distributed on any one portion of the loaded area and half of this load on the remainder of the loaded area, in such a way as to produce the most critical effects on the member concerned." My questions are:
1). Does this mean there are three types of snow loads, uniformly load in the forms of both fully and partial loadings, and nonuniform load?
2). How to apply the partial load to "one portion" of the area? I mean, how to determine which area to apply the full and which area for the other half?
Thanks a lot,
Fiona






RE: Question about National Building Code of Canada snow loads
RE: Question about National Building Code of Canada snow loads
http://www.nrc-cnrc.gc.ca/eng/publications/codes_c...
RE: Question about National Building Code of Canada snow loads
1) It is a judgment call based upon your building configuration to determine which portion gets full load and which gets half.
2) The requirement does not imply full checkerboard loading.
For example if you have a two-span continuous beam, you would want a load combination that put 100% of the snow on one of the two spans and 50% on the other, then a second combination that does the reverse. For a 4-span continuous, probably something like spans 1,2 get full, 3,4 get 1/2; or 1,4 get full, 2,3 get half. The second item above would suggest you don't need a 1,3 full, 2,4 half pattern.
Buildings with gable conditions over 15 degrees are getting boosted due to over-ridge full and partial snow loads per Article 4.1.6.9, so are exempt from the Article 4.1.6.3 provision.
RE: Question about National Building Code of Canada snow loads
Thanks for your explanations. It helps me a lot. I agree with you that NBC2015 improves a lot by putting details into it instead of commentaries. :)
Regards,
Fiona