New York 2007 Code Snow Loads - reduced??

[jfudo]

I'm trying to figure out why the ground snow loads in the new New York State building code are lowered in a majority of the state. I am having a hard time designing to the lower loads, like I'm missing some calculation factors that bring the roof loads back to the old numbers anyway.

Does anyone have any insight here? Thanks...

 

[bjb]

jfudo,

I think that the change in ground snow load may be due to inaccuracy in the way the old snow loads were obtained. Prior to adopting the IBC, New York had its own unique building code that wasn't based on ANSI, ASCE, UBC, BOCA, etc. The old snow loads were originally presented not as ground snow loads, but as roof snow loads, and they were in use for many decades. When NY adopted the 2000 IBC in 2003, they had to take their old roof snow load values and convert them so they could be used with IBC and ASCE 7. They did this by dividing the roof snow loads by 0.7 to get to ground snow loads.

I believe the ground snow loads in the 2007 NY building code (based on the 2003 IBC) are based on more recent studies of snow loads in NY. I just use them and don't try to get back to the older values, which were generally higher than in the current code. I read this somewhere byt can't remember where.

 

[jfudo]

The issue I'm having is the changes from the 2000 to the 2007 building codes. They are both based on IBC. Most of the reductions are only 5psf for Pg.

 

[csd72]

Global warming?

 

[PT999]

What is the new value for Nassau and Suffolk Counties on Long Island.

I only have the first IBC Building Code and Residential Code editions for NYS.

Also what will the new New York City IBC use for ground snow load. Is it out yet?

 

[jfudo]

I think global warming is going to make snow worse for the Tug Hill and other lake effect regions...if any more snow will even fit on the ground there.

Brace yourself PT999, loading on Long Island went from 45psf for Pg to 20psf.

See why I'm having a hard time with it?

 

[Calif]

jfudo:

Does NYC follow the 2006 IBC building Code or the ASCE-7 Minimum Design Load for buildings?

THanks

Calif

The resisant virtues of the structure that we seek depend on their form; it is through their form that they are stable, not because of an awkward accumulation of material. There is nothing more noble and elegant from an intellectual viewpoint than this: to resist through form. Eladio Dieste

 

[PT999]

NYC has adopted (effective July 2008) a new code based upon the IBC (with NYC changes). But its not available to be purchased as of now as far as I can tell.

The 1968 code (still in use until July) called for 30 psf roof snow load.

 

[Calif]

What is the current NYC Buiding codes that is used today and what is the new code that is coming out in July 2008?

Calif

The resisant virtues of the structure that we seek depend on their form; it is through their form that they are stable, not because of an awkward accumulation of material. There is nothing more noble and elegant from an intellectual viewpoint than this: to resist through form. Eladio Dieste

 

[PT999]

New York City traditionally developed its own building code over the years, and the one currently in force is known as the 1968 Code (with changes as adopted from time to time). You can download it from the DOB website.

Just recently, the City adopted a new IBC based Code, but with NYC specific sections, to be effective July 2008.

This new code does not appear to be on sale at the ICC yet as far as I can tell, but apparently is downloadable at the DOB website.

I looked at the Soils and Foundation section, and all of it seemed to be underlined, meaning specific to NYC and different from the regular IBC Code

 

[jfudo]

I didn't know that the City uses a different code than the rest of the state. I'm talking about the State code which is in its second issuanc that is based on the IBC. Nothing else changed very much except for the snow load map.

The calculations are the same as in ASCE 07, but we have a special loading map.

 

[csd72]

maybe this might explain some of the common issues

http://www.alpineequip.com/upload/391/FELDMANNpg24252627.pdf