Seismic Applications

This set of provisions provides minimum design requirements for the incorporation of passive energy dissipation devices in buildings. Energy dissipation devices (also termed damping devices) reduce global and interstory seismic displacement response of structural systems, but may either increase or decrease seismic stresses and accelerations within structural systems. They provide a controlled increase in structural damping, and may also result in an increase in structural stiffness or change in participating mass. Passive energy dissipation systems do not require active control by electrical, pneumatic or hydraulic systems. Buildings designed in conformance with these provisions must also be designed in accordance with all other applicable provisions of the Uniform Building Code, except as specifically defined in this appendix. Design must consider the combined behavior of all elements of both the Lateral Force Resisting System (LFRS) and the Energy Dissipation System (EDS). Energy dissipation devices must not form part of the gravity load – resisting system.

This paper presents the design, analysis, testing and modeling of an electrorheological (ER) fluid damper developed for vibration and seismic protection of civil structures. The damper consists of a main cylinder and a piston rod that pushes an ER fluid through a stationary annular duct. The basic equations that describe the fluid flow across an annular duct are derived. Experimental results on the damper response with and without the presence of electric field are presented. A combination of a simple phenomenological model and a neural network is proposed as a practical tool to approximate the nonlinear and velocity dependent damper response.