Purpose of adding selfweight under seismic definition

Hello forum, 

I have one doubt regarding defining the seismic weight / lump mass / joint weight under the seismic load definition.

What is the purpose of adding selfweight under seismic definition as highlighted in attached image

IMO, it indicates the mass of structure members which is capable of accelerating all direction, results in seismic load on structure itself. And hence selfweight should not be included in the load combination used for Joint weight calculation.

Am I right?

 

  • For generating seismic loads, the building codes multiply the total seismic weight ( say W ) with a coefficient. The W should include the weight of the structure itself in addition to other dead and live loads. The weight of the structure is included through self weight . It is necessary to add the SELFWEIGHT to the seismic weight definition when you are using the equivalent static method and apply selfweight in ALL 3 directions in the mass definition, if you are doing any form of dynamic analysis. 



    Answer Verified By: Vishal Girase