Hi, I have been googling here and there to find some answers for my questions, but no luck.
I am designing a block foundation supporting a compressor skid. Design itself is okay, but I have a little concern about the contact between the foundation and soil. The surface soil at the job site is pretty much tan limestone with clay layers and seams (gray shale was found about 10' deep), which will directly support the foundation. Since it is a weak rock, it will reflect a considerable proportion of the energy that ordinarily be radiated away from the foundation, in effect producing a lower geometric damping ratio than would occur in a softer subgrade.
Some say that I need to throw in a thin layer of sand under the footing to increase damping ratio. Some say that I may want to put a cork layer for the same reason. I am wondering if there's any common practice or recommendation on this issue.
Thanks for your help in advance.
I am designing a block foundation supporting a compressor skid. Design itself is okay, but I have a little concern about the contact between the foundation and soil. The surface soil at the job site is pretty much tan limestone with clay layers and seams (gray shale was found about 10' deep), which will directly support the foundation. Since it is a weak rock, it will reflect a considerable proportion of the energy that ordinarily be radiated away from the foundation, in effect producing a lower geometric damping ratio than would occur in a softer subgrade.
Some say that I need to throw in a thin layer of sand under the footing to increase damping ratio. Some say that I may want to put a cork layer for the same reason. I am wondering if there's any common practice or recommendation on this issue.
Thanks for your help in advance.