Earthquake Analysis with Base Isolators 3

[missstructures]

I am working on a project for my masters degree, and I am trying to find structural plans for a ~20 story building in an earthquake zone so I can model it and analyze it subjected to an earthquake acceleration data, with and without base isolators. I am having trouble finding practical information on the isolators and the properties of the columns, beams etc of buildings to get some ideas for my model. Any suggestions?

 

[Taro]

Your advisor probably knows several former students that would be willing to give you a set of drawings that you could use for your project. My company does this for my old prof. I must admit that it's not purely altruistic, though. It's also a very good way for companies to get to know good students and recruit them in this tight job market.

As for information on isolation systems, call a couple isolation manufacturers and ask them to send you their literature. You can probably also check out Naeim & Kelly's base isolation book from your university library.

 

[Qshake]

Taro is right on course with the advice. For more information on multi-story buildings see Chopra's Dynamics of Structures: Applications to Earthquake Engineering. Twenty stories is a lot and the period (rough estimate of 0.1N = 2.0 seconds) already places overall behavior of the structure out on the response spectra beyond the max response. I suggest that for comparisons sake you use something much smaller, more typical say a 5 story building.

Also, check out Naiem's latest edition of the Seismic Design Handbook. The old edition covered this topic also.

 

[Shahin]

I agree with Qshake about using a smaller building. My master’s thesis was about structural control (both active and passive) with Tuned Mass Dampers. In my thesis I analyzed the linear and nonlinear behavior of 25-story building under earthquakes. As a result of analyses it is seen that by increasing the height of the building, the period of the structure increases. So in such buildings the excitations such as wind and weak earthquakes has more effect. Specially wind since it usually oscillate at the fundamental frequency of the building. For this reason in order to reduce the response of tall buildings, mass dampers are recommended. My suggestion is to use a smaller building or use other passive control devices such as TMD or TLD.

About buildings with base isolation systems, you can see the University of Southern California Teaching Hospital in America, the Computer Center of the Ministry of Post and Telecommunication and the Matumura Research Institute in Japan, the Museum of New Zealand and New Zealand Parliament building and finally city halls in Los Angeles and San Francisco. About references I can suggest you Chopra's Dynamics of Structures: Applications to Earthquake Engineering (as Qshake mentioned) and UBC 1997.

I am at your disposal for more information that you may need. You can mail me to the address: shahinkr@hotmail.com

Regards

 

[rmonterroso]

Missstructures:

I realize your post was about 1 1/2 years ago, so I assume you have already concluded your master's thesis work on the 20 story building with and without base isolation.

I am most interested in obtaining information on your findings, for I have a real life project that I have already designed with concrete dual SMRF/shear walls and now the developers have asked me to look into isolation/damping.

Could you please mail me at mrmv@intelnet.net.gt please?

Thanks