Hey everybody!

I have a question I would like to share and ask you.
We have a soil layer with medium gravel which has a depth of 38 m. We want to build a multi storey framed building safely with a fundamental period of 1.7 sec.Do you think it will be safe?
Vs is given as 750 m/s in the question.

It is also asking the natural period of the layer with 38 m but I cannot find any formula anywhere so I am a bit desperate.

Can you help me please?

8 answers

All I can suggest is that gravel is inherently unstable. When building on unstable soil in California, we drive piling until we reach bedrock. Perhaps another tutor will have a formula for you. Another factor in the stability of a building in a quake is what KIND of framing? Wood? Steel? There's a difference.
http://www.gharexpert.com/articles/Earthquake-2082/Earthquake-Resistant...
I cannot open the page through this link. Should I register or sth?
Ooops! You're right. I'll find another one for you. Give me a minute.
http://en.wikipedia.org/wiki/Earthquake_engineering

http://www.earthquake.usgs.gov/learn/publications/saferstructures

I hope these help.
Thank you so much. I will check them out.
Actually I got the formula and found the answer. Now, I just need to know about the safety when ground's period is greater, equal and lower than the structure's period. Can we say that it is too dangerous if the periods are equal?
I can't help with this. The sites I found aren't very helpful either. Maybe someone else can help. Or keep looking on line and see if you can find opinions as to what is too dangerous.