I was reading FEMA chapter 4 about damping. Can someone please explain to me why concrete has a higher number of critical damping (10%) compared to steel (3%)?
On page 4-12, it says, “for most structures, the amount of damping in the system will vary from between 3 percent and 10 percent of critical. The higher value would apply to older buildings that employed a structure of steel columns and beams encased in concrete… and many heavy fixed partitions… the lower values would apply to a modern office with a steel-moment frame, a light metal and glass exterior, and open office layout with minimum fixed partitions.”
According to the text, critical damping is the least amount of damping that will allow structure to return to its original position. Since concrete is more heavy weight than steel, shouldn’t concrete itself provide more damping than steel, thus requiring less amount of damping?
Thanks so much for your help in advance!
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