英文摘要 |
Since design guidelines for supplemental viscous dampers to building structures are readily available in various seismic design codes, the applications of viscous dampers to reduce the seismic damage potential to of structures and/or non-structures are extensively progressing. These design guidelines are provided often based on the added effective damping ratio contributed by added viscous dampers. However, the distribution method of damping coefficients corresponding to the desired total effective damping ratio is not specified in the current seismic design codes. Therefore, some reasonable distribution method for the damping coefficients may be needed to efficiently and economically design the viscous dampers. This is particularly needed for the vertically irregular building structures such as those with stiffness irregularity and/or mass irregularity. This study aimed at proposing and deriving the distribution methods for added linear viscous damping coefficients in different stories based on the following three concepts:(1) uniformly distributed;(2) proportional to the story shear force of each story divided by the total base shear; and(3) proportional to the elastic strain energy of each story divided by the total strain energy of the structure. For illustration, the elastic responses of three types of building structures equipped with viscous dampers designed according to the aforementioned three methods are presented. The building types include:(1) a vertically regular building;(2) a building with vertical stiffness irregularity, e.g. a building with soft stories; and(3) a building with vertical stiffness discontinuity, e.g. a setback building. The numerical study indicates that the distribution method based on the elastic strain energy, compared with the other two distribution methods, is more effective in reducing the seismic responses of the structures, particularly for the building with soft stories. |