Control structure with rotary force limiter and energy dissipater

A force limiting and energy dissipating seismic control base isolation structure comprising;

• a rotary yield unit having a plurality of elastoplastic flexural members, the rotary yield unit having a first part and second part rotatably connected, the first part of the rotary yield unit pivotably connected to a first structure, the first structure being a superstructure;
• the second part of the rotary yield unit located and secured to a second structure, the second structure being a foundation structure and providing only gravity support to the first structure;
• the rotary yield unit able to rotationally cyclically displace;
• the rotary yield unit maintaining a constant resistive yield torque within itself and a constant resistive yield force across itself and between the first and second structures;
• and
• the constant resistive yield force between the first and second structures enabling the first structure to be dynamically separated or isolated from the second structure, by the constant resistive yield force produced by the rotary yield unit providing a control structure located between the first and second structure and enabling the control structure to control and limit forces developed within itself, and control and limit forces developed between the first structure and second structure, and able to control and limit response accelerations and dynamic forces developed within masses of the first structure, as the first structure and second structure displace relatively, and resist and endure with constant resistive yield force between the first and second structure generated by base motion or ground motion input due to a seismic event.