Maximum damping forces for structures with viscous dampers under near-source earthquakes

• The inelastic response of structures with viscous dampers under near-source earthquakes is investigated.
• The inelastic velocity ratio (IVR) is used to predict the maximum effective forces of dampers.
• The most critical parameters that affect the IVR are considered.

This paper examines the inelastic response behaviour of structures with supplemental viscous dampers under near-source pulse-like ground motions. It is well known that the design of dampers requires the effective evaluation of maximum seismic velocities or maximum damping forces. In order to avoid complicated methods, such as the dynamic inelastic analysis, this study proposes a simple and effective evaluating method for these maximum values using the inelastic velocity ratio. This ratio is a modification factor which allows the evaluation of the maximum inelastic velocity or damping force from their corresponding elastic counterparts. The paper focuses on structures. Extensive parametric studies are conducted to examine the influence of characteristics of structure (period of vibration, post-elastic stiffness, force reduction factor), of supplemental damping (equivalent viscous damping ratio) and of ground motion (type of earthquake fault) on the maximum seismic velocities and damping forces.