Extracted text: 4- of the structure supported at the base with ....... appropriate springs and subjected to a base excitation. The study is performed on the simplified oscillator model. For flexible structures, the effect of interaction is to reduce the spectral acceleration. Dynamic analysis Direct Approach a) b) Evaluating the soil-foundation characteristics Determining the foundation input motion Boş bırak KÖnceki 4/20 Sonraki> Карat