Hi guys,
There is a question that I think lost of seismic designer often wonder about that is if there is torsion in first two modes, is that model always considered bad model? I found this in IS 1893:2016 that strictly states this (please see the picture below).
“torsional mode of oscillation shall be smaller than those of the first two translational modes along each of the first two translational modes along each of the principal plan directions.”
And I wonder, is there any item in IS 1893:2016 tells us about what should we do if we are in case that torsion is inevitable ( like when the owner and architecture don't let us revise a complex structural plan that leads to torsion in first two modes). Please help, thank in advance.
Mazhar Amin reacted to a post in a topic:
Does torsion in the first 2 modes considered bad designed
