From the paper "Seismic soil pressure for building walls: An updated approach" by Farhang Ostadan (2005), I tried to do the steps given in the paper but I am stuck in following the approach. Any assistance will be appreciated?
In the attached image 1, at 30% damping in deepsoil, is it the same way as given in image 5? At the same time "Perform free-field soil column analysis and obtain the response motion at the depth corresponding to the base of the wall in the free-field. The response motion in terms of acceleration response spectrum at 30% damping should be obtained". I obtained a result as given in image 2. is it okay?
"The material damping in the soil was specified to be 5%" Does it mean that in the input given in image 4, it should read as 5.0?
Hi Ahmed:
I think your response spectra output is overrated. I mean, when I deconvolutionate a soil of similar characteristics, the maximun acceleration of soil reduces to half.
Consider this:
- The paper explain the result output should be 30% of damping ration. NOT as input.
- The material input uses 5% with the assumption of low shear strains. Then, the input is 5% and not 0.5%.
- Try using a big depth using discrete divisions of 1 meter.
Hope this approach can solve your problem.
Best regards.
You will perform free-field site response analysis with small strain stiffness and damping ratio, extract the acceleration time history at the corresponding depth (basement raft level), then convert acceleration time history to acceleration response spectra of SDOF system at 30 damping ratio.
Is there anyone who can do an example using this approach. Thank you Mr. Charbel Chapana and Mr. Sadiq Shamsher .
Mr. Sadiq Shamsher " then convert acceleration time history to acceleration response spectra of SDOF system at 30 damping ratio. " how?
Please read Structure Dynamics book by Chopra. Its very basic concept how to convert acceleration time history to the acceleration response spectra at any damping ratio.
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