Abstract : This report investigates the seismic response of intake-outlet towers. The effect of different ground accelerations at the supports of the tower and inspection bridge is examined. The water outside and inside the tower is accounted for by added masses. The accelerations at the bridge support and tower base are obtained from a finite element model of the dam and soil foundation. The other effect examined is the soil-structure interaction. First, a direct approach based on a finite element model of the tower, bridge, and dam with the earthquake motion applied at the bedrock is used. The second approach uses a frame model of the tower and bridge with springs and dashpots accounting for the soil-structure interaction. This simple model provides reasonable results if adequate values of the torsional spring are used. The effects of the soil-structure interaction proved to be much more important than the multiple support excitation.