Mass For Wind Analysis

[Nodan]

Hello all,

Natural frequency is required for wind load analysis. However how do you calculate the mass?
With full live loads or 0.30*Live like for earthquake analysis.

 

[malikasal]

why don`t you use the procedure in ASCE 7-10 26.9.2.1 , that is if your structure is within the limitation outlined in that section of course.



ôIf you don't build your dream someone will hire you to help build theirs.ö

Tony A. Gaskins Jr.

 

[JoshPlumSE]

Philosophically, you want to get the actual mass of the structure when the wind loads are expected. So, normal loading for the structure. A realistic dead load (rather than a conservative / worst case value). You might take a look at Section 12.7.2 (Effective Seismic Weight) and its commentary for general philosophy. It's got criteria on storage loads, snow loads and such.

 

[slickdeals]

I typically like to use 25% of live load for contributing towards mass for wind loads on our residential towers. Refer to SP-240 (Wind Tunnel Methods). They don't have a set percentage value, they recommend 25-50%.

http://www.cppwind.com/wp-content/uploads/2014/03/240-6.pdf

The basis for 25% is based on survey done which concluded that the actual load is only about 6 psf (out of the 40 psf design load). Reference Table C4-2 of ASCE 7-10. Therefore, using 25% instead of 15% surveyed.

A survey conducted shows that 85% of respondents use 25% of live load as "sustained" for the mass.

https://www.concrete.org/publications/internationalconcreteabstractsportal/m/details/id/51689517

 

[MotorCity]

To be consistent, you should use whatever mass (i.e. DL or LL) is included in the same load combination as wind.

For example if your load combination has 0.5L + W, use 50% of the live load.