Abstract
Frequency characteristics of spring constants at both ends of a suspended transmission line subjected to horizontal periodic dis placements at one end are obtained theoretically by using the method of modal analysis and by analyzing the equations of motions directly. Both results agree well with each other and with the experimental results of a transmission line model. They show that the spring constants at both ends are not always equal and positive, but have frequency domains in which the spring constants are negative. The time histories of additional tensions in a transmission line subjected to earthquake-like excitations are computed by using the former method, and it is presented that only a few vibration modes which have large tension modes contribute to the seismic responses for tensions in a transmission line.
