I have a 2-story heavy timber frame structure (simple gable roof, square structure) that is being constructed with a clay/wood chip matrix as the wall insulation and drywall support. I'd like to account for the weight( as it is significant) of the earth walls without accounting for any of its rigidity when I run my simplified static lateral analysis. Any thoughts on how to apply such a dead load to the wall spaces of my wire frame model. My initial thought was to resolve the wall weights into vertical line loads along each story line, but id like to get away from that as I feel it doesn't accurately represent what is really happening at the ground floor.

thanks

Is this mix called "Rastra"?

Why not just hand caloculate the mass and lump the appropriate amount of mass at the roof and floor diaphragms?

Mike McCann
MMC Engineering

 

Mike,

the construction technique is a variation of Leichtlehmbau , which from what I understand is a German term for light straw clay. Basically wood lath infilled with the mix and then typically covered with an earth plaster.

I 100% agree with your suggestion, the hand calc is done. I'm a RISA rookie though, so the the real heart of my question is how to actually accomplish what you've suggested in the program itself.

Ive designed the model such that there is a plywood "plates" over floor or roof joist. Is it simply a matter of adding mass to these plates and if so how?

thanks

oh I got it, dead load to the diaphragms to represent the mass of the wall.

thanks again

All I do is add the calculated lumped seismic force to nodal points in the structure within one of the structure load pages.  I label it seismic.  I apportion the force by weighted area.

So figure out what the lateral force contribution of the walls is and distribute it at nodal points in the structure you describe.

 

Mike McCann
MMC Engineering