Seismic Design Of Structures With Added Viscous Dampers In Diagonal Scissor-jack Braces

Performance-based seismic design is the key research direction of seismic designresearch field in recent years. The philosophy of performance-based earthquake engineering isto design a structural system to sustain a pre-defined level of damage under a specified levelof earthquake intensity, in which the selection and arrangement of dampers in the passiveenergy dissipation systems is a key point. Providing the added damping to improve theseismic performance of structure is the main difference with the traditional structure, whichmainly depends on the plastic hinge to consume the input seismic energy. Many scholars havealready studied the traditional installations of the dampers in passive energy dissipationsystems.This paper proposes a new installation of the dampers, i.e., improved added viscousdampers in diagonal scissor-jack braces. This paper conducts some research about existingproblems in the seismic design of structures with added viscous dampers in diagonalscissor-jack braces.This paper explores the simplified seismic design and the analysis method of the addedviscous dampers structure, introduces mechanical characteristics of viscous dampers andanalyzes the linear and nonlinear viscous damper. In addition, formula of damping ratio oflinear viscous dampers and nonlinear viscous dampers is introduced. This paper also studiedthe influence of the additional damping ratio caused by bending deflection of the framework.All the above lay the foundation for research of improved added viscous dampers in diagonalscissor-jack braces.This paper introduces the installation of the dampers in improved added viscous dampersin diagonal scissor-jack braces and deduces amplification coefficient expressions ofdisplacement and force of viscous dampers in improved added viscous dampers in diagonalscissor-jack braces according to the theory of small deformation. On the other hand this paperstudies the computing method and formula of added damping ratio in improved added viscousdampers in diagonal scissor-jack braces considering the influence of the added damping ratiocaused by bending deflection of the framework in high-rise buildings. At the same time, the the advantages and disadvantages of this damper installation is also pointed out, which cannot only significantly magnify damping force offered by viscous dampers but also reduce theburden of its beams and columns.Performance-based seismic design about improved added viscous dampers in diagonalscissor-jack braces has been studied. Firstly, it confirms the performance objective of thestructure. Secondly, it determines the required added damping ratio when the structure meetsperformance objective using capacity spectrum method. Thirdly, different types of dampersare installed on each floor in three ways: uniform distribution, damping coefficientproportional to storey drift and damping coefficient proportional to storey shear force. Finally,the structure with improved added viscous dampers in diagonal scissor-jack braces isanalyzed using nonlinear dynamic analysis, in order to verify the effectiveness ofperformance-based seismic design about improved added viscous dampers in diagonalscissor-jack braces and estimate the optimum allocation for dampers. At the end, it comparesresults of nonlinear dynamic analysis of improved added viscous dampers in diagonalscissor-jack braces and traditional added viscous dampers in diagonal scissor-jack braces.Analysis results indicate the improved added viscous dampers in diagonal scissor-jack braceshas better seismic performance.