Research and Development of Viscous Fluid Dampers for Improvement of Seismic Resistance of Thermal Power Plants: Part 12 Vibration Measurement of Existing Boiler Structure

Thermal power generation is a very important power source until renewable energy or carbon-free energy become widespread. Japan is one of the most earthquake-prone countries in the world, and coal-fired power plants have been damaged by major earthquakes. For example, strong earthquakes such as the Great East Japan Earthquake in 2011, the Hokkaido Eastern Iburi Earthquake in 2018 and the earthquake off the coast of Fukushima in 2021 caused coal-fired power plants to shut down for long periods of time, and these had a significant impact on society. Therefore, it is important to improve the seismic safety of existing coal-fired power plants in earthquake-prone countries such as Japan. The authors have proposed an application of visco-elastic dampers to a boiler structure in a coal-fired power plant to improve seismic performance. In our past papers, development of the damper, manufacturing and various experimental tests of prototypes were carried out, then the application of the damper was effective to reduce the base shear force of a support structure of the boiler, and the dampers had a long lifetime for continuous deformation. In order to effectively apply these dampers to a boiler structure, it is important to construct an analysis model of the boiler structure for suitable distribution of dampers. Thus observations of actual seismic response of the boiler structure to build an accurate analysis model are required. Therefore, this paper deals with a long-term vibration measurement of seismic response of an actual coal-fired thermal power plant in Japan. The long-term vibration measurement will also effective for early detections of damage due to aging or earthquakes. A system of the vibration measurement and an example of the measurement results will be reported in this paper.