How to apply live-load in SeismoStruct

02-Getting started with the modelling
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Mojtaba Moosavi
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Joined: 18 Aug 2016, 08:13

How to apply live-load in SeismoStruct

Post by Mojtaba Moosavi »

I am modelling a 3-story structure but I don't Know how to apply live load, since in applied load tab just permanent load type is mention, there is nothing that can distinguish live-load from dead-load, but as you know for calculating mass of structure the participation of each of these two kind of loads are different. As the time is very important matter in this case, I appreciate your quick answer in advance.
huffte
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Re: How to apply live-load in SeismoStruct

Post by huffte »

Hi Mojtaba. I am not certain that I understand your request, but I will attempt an answer.

Some analysts might argue that if the live load is present during ground shaking, then it should be included as part of the mass.

It seems that you wish to apply live load as a loading, but not include it in the mass of the structure. I believe to do so that you will have to input both the live loads and dead loads as permanent loads. Next for all of the beams carrying floor load, you would calculate the supported dead load not already included in the element self-weight. Add this as additional mass in the Element Class definition tab.You would then in the Gravity and Mass tab of the Project Settings, specify that you want mass to be derived from Frame Elements and Mass Elements (not loads).

Alternatively for the mass definition, you could zero out all element material densities, hand calculate the joint lumped masses and apply them as element classes.

It is a good question you ask, Mojtaba. SeismoStruct is an excellent tool in my view. If this sort of issue is something you will need often, and if neither of the above methods suits your needs, then perhaps you might wish to put in a request to the development team in the 05-Future Developments and Requests section of the SeismoStruct forum.

Best of luck Mojtaba Moosavi.
Tim Huff
Mojtaba Moosavi
Posts: 2
Joined: 18 Aug 2016, 08:13

Re: How to apply live-load in SeismoStruct

Post by Mojtaba Moosavi »

Hi Tim,
thanks for your comprehensive answer. I get your point, but what I am struggling with is what percentage live load should take and where I can apply this coefficient. For instance in Iranian seismic code(Standard 2800), it is mentioned 20 percents, and as you know it is for seismic mass of structure not for applying load itself. As an conclusion, we apply all(100 percent) live load, but for calculating mass of structure it should take only 20 percents of it, so there should be a tab,section any thing to allow us input this coefficient, which is my problem because I can't.
Then again I appreciate your answer, and wish you best of luck for .
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seismosoft
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Re: How to apply live-load in SeismoStruct

Post by seismosoft »

In SeismoStruct Gravity and Live Loads are treated in the same way are Permanent Loads that are applied at the beginning of the structure.
You simply have to add the gravity loads and the live loads you want to apply to the structure
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