טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentJulia Kalaev
SubjectSeismic Retrofitting of Wall Structures Using Viscous
Dampers Mounted on a Few Stories
DepartmentDepartment of Civil and Environmental Engineering
Supervisor Professor Lavan Oren
Full Thesis textFull thesis text - English Version


Abstract

Recently, along with a generally increasing awareness of seismic risks among the structural engineering community regarding the enhancement of the seismic performance of new and existing structures, usage of seismic devices in new or retrofitted buildings in order to control the seismic response is on the rise.

One of the approaches of seismic retrofitting relies on fluid viscous dampers (FVD). Fluid dampers have several inherent advantages compared to other types of energy dissipation devices. One of them is that the output force of a fluid damper is out of phase with primary shearing and bending stresses in the structure due to displacements. This means that the damper can reduce both force related and displacement related responses while eliminating the need for strengthening pillars and foundations. In addition, absolute accelerations in the building are expected to be lower because FVDs improve the building’s response without significantly boosting structural stiffness.

Most of the research on design with seismic retrofitting was focused on framed structures. Some recent research was done also on wall structures indicating that FVDs could also lead to an efficient response reduction in these kinds of structures by mounting them in strategic locations. Since the cost of the dampers depends primarily on their number throughout the building appropriate initial design tools, which will lead to the minimum number of dampers and thus to the minimal retrofitting cost, are very important.

To further make this approach more attractive and cost-effective, it is the aim of this research to equip the engineer with insight and tools for the seismic design of viscously coupled walls or trusses with dampers located in discrete locations throughout the height. The study was conducted, and a discussion is presented, assuming dampers in up to two locations simultaneously. The controlling parameters of such systems and their effect on various responses of interest are first identified and analyzed. The results of this study are then presented in graphs that can be easily implemented in practice for the purpose of initial design.  Furthermore, these results are discussed and some insight as to the most efficient locations for the damper is given.