ABSTRACTViscoelastic (VE) dampers have been shown to be an effective energy dissipation device for structures subjected to seismic excitations. When a VE damper is under shear deformation, the temperature within the damper material will rise due to the conversion of mechanical energy into heat. The effect of temperature rise in the VE damper on a viscoelastically damped structure may be significant because the damper stiffness can decrease due to the temperature rise in the VE damper and its energy dissipation capacity may reduce under strong earthquake ground motions. This paper is intended to quantify the temperature rise effect. A VE element which can accurately describe the frequency and temperature dependent behavior of the test results of a VE damper is first presented. The effect of temperature rise within the VE material is included. Seismic response analyses of a viscoelastically damped structure which was studied extensively by shaking table tests are carried out by two analytical methods: a frequency domain analysis and a time domain analysis. Both analyses consider the effects of frequency and ambient temperature of the VE dampers. The frequency domain approach is computationally more efficient. However, it neglects the effect of temperature rise in the analysis. The time domain method is computationally less efficient. However, it can explicitly calculate the temperature rise during the earthquake and evaluate its influence on the structural responses. Finally, parametric studies on the effect of temperature rise within the VE damper material on the seismic response of a viscoelastically damped structure are analyzed and its implications on practical applications are discussed.
Variations between foundation-level recordings and free-field earthquake ground motions: numerical study at soft-soil sites
