抄録
The basic measure against a vibration proof design is to take effective steps to vibration proofs and to keep vibrating generators and precision machines apart as far as possible. As one of the effective measures against the vibration proof, a vibrating generator is installed on the underground stories. But it's impossible to install all the vibrating generators there. The author can't help installing the medium vibrating generators on the flat slabs near the precision instruments. The purpose of this study is limited to solve the effective mass for the slabs with arbitrary thin length ratio. As support conditions the author calculated the 1st; the simply support along edges, the 2nd; the fixed support along edges, the 3rd; two adjacent edges simply supported and the other edges built-in, the 4th; the semi-fixation.
