In a dynamic response analysis of structure-ground system, we often use spring-mass model. A propagation characteristics of an earthquake force between structure and surface ground is shown in dynamic K-value. We generally obtained K-value from the results of vibration test of structure or its model. But the vibration test is very expensive and offhand.
Therefore, this paper suggests an analytical method of a dynamic K-value in a laboratory based on a hybrid experimental method. A hybrid experimental apparatus for analysis of K-value is composed of micro-computer and dynamic tester. We calculate the dynamic behavior of structure by a micro-computer and obtain an earthquake force due to the relative displacement between structure and ground by a dynamic tester.
As an analytical case, we analyzed the dynamic K-value of between surface ground and structure during an earthquake.