damping ratio in direct integration time history analysis

[umeshlamichhane]

how to provide constant damping ratio for direct integration time history in sap2000?
if possible how can we provide 1% damping ratio for progressive collapse analysis?(vertical motion)

 

[JoshPlumSE]

I'm more knowledgeable about linear time history analysis. And, for a linear direct integration Time-history analysis you cannot get constant damping across all frequencies. At least not when using standard Raleigh damping.

Instead you usually want to set the M and K damping constants (see link for CSI wiki on the subject).

The key then is to set these values so that the damping is relative constant for the frequency range you're most interested in. It won't be completely constant, obviously, but it can be reasonably constant.

 

[umeshlamichhane]

Thankyou sir.For my question i found the solution as