System to improve seismic resistance of stacksPantograph Damper

  • Disaster Prevention
  • Infrastructure
  • Maintenance & Management

We directed our attention towards the deformation mode of the main posts in the lower section of the steel tower. To effectively dampen vibration, we utilized a pantograph damper, which amplifies axial displacement of the posts through toggle mechanisms and regulates the response.

Main points

  • Improved seismic performance without compromising existing seismic and wind resistance
  • Installation is only required for the first section, reducing the need for work at heights, and thereby improving safety during construction
  • For tower-supported steel stacks, installation can be carried out while the stack is in operation (no need to shut down the plant or facilities)
  • Can be introduced at a relatively low cost in a short period of time due to the lack of work in high places

Principle and mechanism of pantograph damper

We directed our attention towards the deformation mode of the main posts in the lower section of the steel tower. To effectively dampen vibration, we utilized a pantograph damper, which amplifies axial displacement of the posts through toggle mechanisms and regulates the response.

*1 A toggle mechanism is a system that amplifies the response based on the principle of leverage.
*2 A simplified design method created by Shinji Ishimaru (former professor of the Department of Architecture, College of Science and Technology, Nihon University) and others

Vibration control effect of pantograph damper

To anticipate large-scale earthquakes (such as earthquake A and B), we conducted earthquake response analysis to verify the effectiveness of a pantograph damper in controlling vibrations.

Verification: Confirmation of high vibration control effect via vibration and performance tests

Seismic response analysis was conducted under the assumption of a large-scale earthquake (earthquakes A and B below) to verify the vibration control effect.

Example of application: Tower-supported steel stacks in Anegasaki Thermal Power Station

Pantograph dampers were introduced to two 200-meter tower-supported steel stacks.

Stack units 5 & 6 and 3 & 4 at Anegasaki Thermal Power Station (TEPCO Fuel & Power, Incorporated)