Seismosoft | Earthquake Engineering Solutions

hi
I do Eigenvalue analysis of 6 story building.how determint the Vertical period.tanks

bakhtiyar, as long as you have "Z" included as a global mass direction in the "Mass and Gravity" tab of the "Options", and as long as you find enough modes, you should eventually get the vertical modes as well.

For example, create a model for eigenvalue analysis using all of the default options (except specify eigenvalue analysis) and the default number of modes in the "Eigenvalue" tab of the "Options" is 10. If you accept these defaults you won't find any vertical periods. In changing the number of modes to 16, you will find that some of the high modes are in fact vertical modes.

tanks huffte
I want Eigenvalue analysis of 6 story RC building with infill panel how Reduced stiffness infill panel because periods is very low.

Sir i have to find the natural periods for the bridge columns shown in following presentation (the Gravity load is 19.24 ton)
https://drive.google.com/file/d/0B7rekW ... sp=sharing
The gravitational load of 19.24 ton was divided in four parts (25%, 50% 75% and 100%)and time period for theses four stages will be have to be evaluated.
Now i am not sure how these masses have to be provided in eigenvalue analysis ??
Kindly guide me in this respect..

A lumped mass element should do the trick zsaeed. You'll find these on the Element Classes tab. I think you would be well served by creating a few models using the Wizard feature to gain some expertise on modeling in SeismoStruct. Best of luck.

Well said Sir ..i defined Lumped Concentrated Mass element for it but when i open the dialogue box the terms Mx My and Mz are confusing me.
1.Is this a load or some Moment to be calculated by the user )..
2.Do i have to enter values for Mx and My (Putting Mz = 0) ..
3. My column was having a load of 19.24 Mton or Tonne in the form of Concrete blocks then for value of Mx and My do i have to enter 19.24 or some other value ..


Thanks

Dear zsaeed,

You have posed the same question in several posts (some of which Seismosoft is likely to remove, since they are plain repetitions), which is neither needed nor helpful.

Your (repeated) query gives me the impression that you did not really read the Help System/User Manual of the program, which is something that I instead would strongly recommend you to do.

I would also suggest you to carefully go through the Verification Report, and corresponding examples, for more useful insight.

Finally, you should also always use hand-calculations to check the results of your (at least first) models, and thus gain confidence in your modelling assumptions. (for instance, you could have very easily computed by hand the period of vibration of a SDOF oscillator, compared it with the results obtained using SeismoStruct, and thus understand in which units you should be defining your mass).

Finally, and as others have noticed already, reading of a good textbook on Structural Dynamics and consultation of the vast (online/journal/conference) literature on this subject, will always be a wise thing to do before trying to embark on complex dynamic modelling of structures.

Rui