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Reinforced concrete chimneys with steel liners are widely used in waste gas discharge of industrial facilities, and guaranteeing their safety performance in harsh environments is important for industries and society. This paper proposes a novel method for the reduction of along-wind vibration in chimneys with liners by tuning the movement of the suspended liners to the response of the outer cylinder, and the conventional rigid supporting platform is replaced by a combination of radial horizontal tuning systems and vertical suspension systems. This ‘tuned liners’ method is applied to a simplified beam-like model that is able to capture the liners/chimney interaction and is validated against a more detailed finite-element shell model. A design method is proposed to obtain parameters of the tuning system that lead to significant reductions of along-wind vibrations whilst satisfying the relative response requirement. A comprehensive study of the structural vibration under stochastic wind actions is performed to demonstrate the effectiveness of the proposed system. The characteristics of the relative vibration of the outer cylinder and the liners are studied. Comparison with conventional TMD solution is conducted to further explore the advantage of the tuned-liners system under stochastic wind actions. The results indicate that the top displacement and acceleration of the outer cylinder are effectively reduced by 62% and 70% with the tuned liners, respectively. A similar performance using a conventional TMD would require an auxiliary vibrating mass that is approximately 300 tons, which is avoided with the proposed tuned liners. Results show that the proposed technique could be effective in the along-wind control of chimneys in multiple directions, even with some unintentional eccentricities.

Wind energy is one of the most mature renewable energy technologies and has been developing rapidly in recent years. Many countries have shown interest in utilizing wind energy, but its impact on the environmental is a concern. The primary environmental impacts include avian safety issues, biosystem disturbances, noise, visual pollutions, electromagnetic interferences, and local climate changes. This chapter provides a review and summary of the environmental impacts caused by the wind energy industry. Available mitigation technologies to minimize these adverse environmental impacts are also discussed. In addition to environmental impacts, structural safety is becoming an issue as many structural failures of wind turbines have been reported. A summary of studies related to these structural safety problems are included in this chapter; the focus here is on the structural performance of wind turbine towers under wind and seismic loads together with health monitoring and vibration control technologies. The intention of this chapter is to provide state-of-the-art knowledge about the aforementioned issues associated with wind energy development as well as strategies for wind energy planners and developers to mitigate the negative effects.

Carbon dioxide (CO2) capture and geological storage (CCS) is one of promising technologies for greenhouse gas effect mitigation. Many geotechnical challenges remain during carbon dioxide storage field practices, among which effectively detecting CO2 from deep underground is one of engineering problems. This paper reviews monitoring techniques currently used during CO2 injection and storage. A method developed based on measuring seismic microtremors is of main interest. This method was first successfully used to characterize a site in this paper. To explore its feasibility in CO2 storage monitoring, numerical simulations were conducted to investigate detectable changes in elastic wave signatures due to injection and geological storage of CO2. It is found that, although it is effective for shallow earth profile estimation, the surface wave velocity is not sensitive to the CO2 layer physical parameter variations, especially for a thin CO2 geological storage layer in a deep underground reservoir. Keywords: Microtremor, CO2 storage, Passive surface wave, Site characterization, Feasibility study