As an effort to minimize material utilization, seismic steel dampers designed to deform inelastically in an in-plane flexural mode have attracted serious attention recently. This paper presents a new type of metallic ...As an effort to minimize material utilization, seismic steel dampers designed to deform inelastically in an in-plane flexural mode have attracted serious attention recently. This paper presents a new type of metallic yielding damper referred to as the in-plane arch-shaped damper modified from its portal frame-shaped counterpart by replacing the straight beam with a circular arch to minimize the effects of stress concentration and warping, and therefore to avoid premature failure. Component tests of both the portal frame-shaped and arch-shaped in-plane dampers were conducted for comparison. Hysteresis loops obtained from the component tests under cyclic loads indicate substantial improvement on the energydissipative characteristics of the proposed damper. Moreover, seismic performance assessment of the proposed damper was carried out further via shaking table tests of a five-story model frame. Encouraging results have been achieved in terms of acceleration reduction, damping enhancement and peak suppression of the frequency response functions, suggesting the potential of the proposed device to be used in earthquake-resisting systems.展开更多
The 285.5 m-high Xiluodu Arch Dam is located in a seismic region along the Jinsha River in China, where the horizontal components of peak ground accelerations for design and checking earthquakes have been estimated to...The 285.5 m-high Xiluodu Arch Dam is located in a seismic region along the Jinsha River in China, where the horizontal components of peak ground accelerations for design and checking earthquakes have been estimated to be 0.355 g and 0.423 g, respectively( g is the gravitational acceleration). The ground motion parameters of design and checking earthquakes are defined by exceedance probabilities of 2% over 100 years and 1% over 100 years, respectively. The dam shape was first selected and optimized through static analysis of the basic load combinations, and then adjusted after taking into account the seismic loads. The dam should be operational during and after the design earthquake with or without minor repairs, and maintain local and global stabilities during an extreme earthquake. Both linear elastic dynamic analysis and nonlinear dynamic analysis considering radiation damping, contraction joints, and material nonlinearity were conducted to assess the stress in the arch dam.The dynamic analysis shows that the maximum dynamic compressive stresses are less than the allowable levels, while the area with tensile stress over the limit is less than 15% of the dam surface and the maximum contraction openings range from 10 mm to 25 mm. The arch dam has sufficient earthquake-resistance capacity and meets the safety requirements. Nevertheless, steel reinforcement has been provided at the dam toe and in the zones of high tensile stress on the dam surface out of extra precaution.展开更多
基金TSC under contract MOST 103-2625-M-009-014the Science&Technology of Fujian Province,China under Project No.2017J01495
文摘As an effort to minimize material utilization, seismic steel dampers designed to deform inelastically in an in-plane flexural mode have attracted serious attention recently. This paper presents a new type of metallic yielding damper referred to as the in-plane arch-shaped damper modified from its portal frame-shaped counterpart by replacing the straight beam with a circular arch to minimize the effects of stress concentration and warping, and therefore to avoid premature failure. Component tests of both the portal frame-shaped and arch-shaped in-plane dampers were conducted for comparison. Hysteresis loops obtained from the component tests under cyclic loads indicate substantial improvement on the energydissipative characteristics of the proposed damper. Moreover, seismic performance assessment of the proposed damper was carried out further via shaking table tests of a five-story model frame. Encouraging results have been achieved in terms of acceleration reduction, damping enhancement and peak suppression of the frequency response functions, suggesting the potential of the proposed device to be used in earthquake-resisting systems.
基金supported by the Program of Study on the Standard of Overall Safety Control of High Arch Dam of PowerChina Co.,Ltd.(Grant No.DJ-ZDXM-2014-19)
文摘The 285.5 m-high Xiluodu Arch Dam is located in a seismic region along the Jinsha River in China, where the horizontal components of peak ground accelerations for design and checking earthquakes have been estimated to be 0.355 g and 0.423 g, respectively( g is the gravitational acceleration). The ground motion parameters of design and checking earthquakes are defined by exceedance probabilities of 2% over 100 years and 1% over 100 years, respectively. The dam shape was first selected and optimized through static analysis of the basic load combinations, and then adjusted after taking into account the seismic loads. The dam should be operational during and after the design earthquake with or without minor repairs, and maintain local and global stabilities during an extreme earthquake. Both linear elastic dynamic analysis and nonlinear dynamic analysis considering radiation damping, contraction joints, and material nonlinearity were conducted to assess the stress in the arch dam.The dynamic analysis shows that the maximum dynamic compressive stresses are less than the allowable levels, while the area with tensile stress over the limit is less than 15% of the dam surface and the maximum contraction openings range from 10 mm to 25 mm. The arch dam has sufficient earthquake-resistance capacity and meets the safety requirements. Nevertheless, steel reinforcement has been provided at the dam toe and in the zones of high tensile stress on the dam surface out of extra precaution.
