A semi-active vibration absorption and energy dissipation control system for restraining vortex-induced vibration of bridges, comprising a spring end plate fixed on a bottom plate of a main beam, a linear tensile spring, a plurality of vertical suspension ropes, a plurality of sliders, a slideway, a first high-strength rope, a first pulley, a second pulley, a second high-strength rope, a mass body, a pulley fixing device, an energy dissipation device, an electric control jack and a controller, wherein the spring end plate is fixed on the bottom plate of the main beam and used to fix a starting end of the linear tensile spring so that the linear tensile spring is arranged horizontally;
- the plurality of vertical suspension ropes and the plurality of sliders are connected and arranged at intervals to provide vertical suspension points for the linear tensile spring;
- the sliders are embedded in the slideway fixed on the bottom plate of the main beam;
- one end of the first high-strength rope is connected with a second end of the linear tensile spring, and the other end of the first high-strength rope is fixed and wound on the first pulley;
- the first pulley is coaxially fixed with the second pulley, and the diameter of the second pulley is larger than the diameter of the first pulley;
- an upper end of the second high-strength rope is fixed and wound on the second pulley, and a lower end of the second high-strength rope is connected with the mass body;
- the first pulley and the second pulley are supported below the bottom plate of the main beam by the pulley fixing device;
- the energy dissipation device is connected with the electric control jack which is fixed below the bottom plate of the main beam;
- the controller is used to control the electric control jack so as to drive the energy dissipation device;
- the mass of the linear tensile spring, the stiffness of the linear tensile spring, the mass of the mass body and the diameter ratio of the first pulley and the second pulley are adjusted to make a vibration frequency of the semi-active vibration absorption and energy dissipation control system close to a vibration frequency of a bridge;
- the principle of resonance energy absorption is used to transfer a vibration energy of the bridge to the semi-active vibration absorption and energy dissipation control system, and friction between the energy dissipation device and the second pulley is used to dissipate a total energy of the semi-active vibration absorption and energy dissipation control system to suppress the vibration energy of the bridge.