Resistant force model of viscous damping wall considering influence of loading frequency

Due to the heterogeneity and velocity-dependency of viscous fluid, it's quite difficult to simulate the dynamic behavior of viscous damping wall (VDW). The existing formulae for resistant forces need different parameter values for different loading frequencies. This may lead to large errors in resistant forces of VDWs subjected to an earthquake with large frequency change. A small-scale shaking table test and a large-scale dynamic actuator test were performed to investigate the influence of loading frequency, showing that direct data fitting with a single set of parameter values for different frequencies will lead to erroneous hysteretic cycles. Based on experimental results, five assumptions were proposed and thereafter a unified model was developed considering the influence of loading frequency by means of introducing the effect of loading history. The proposed model was validated with satisfactory accuracy in predicting the test results.