Expert: Dr. Abdulaziz Jarkas - 3/3/2007

Question
Hey there. My name's Anie and I'm taking a class in Environmental Science. We are studying earthquakes and we have the option of presenting something in relation to the class. My group would like to show the class earthquakes and its effects on buildings. We're using wooden sticks and our teacher has an apparatus for "earthquakes" he built a while ago. So, if you can, what is the easiest but strongest design or structure for an earthquake resistant skyscraper but in smaller scale and wooden? We want to make it with a square base and about 3 stories. We propose it to be around 45 cm tall with each story about 15 cm, and the base 22.5 x 22.5 cm. We want no solid walls either. We researched cross bracing, etc. but there are so many designs to choose from!! Any of your help would be much appreciated! Thanks in advance!

Anie

Answer
Dear Anie,

I'm sorry, but I have received your message only today, thus I apologize for the delay in response.

Certainly, the trick here is to have an adequate bracing, the cross option is a good one. However, please remember that an earthquake is basically a horizontal acceleration of the building, therefore, the stiffer the base and the joints of the building, the best for resistance.

In view of the above, and since I no nothing about the geometry of the building, my advice to you is to provide the braces on the weak joints. You can easily locate such joints by inspection.

Hope this helps, and good luck with your project.

Kind regards,

Dr. A. Jarkas