Nonlinear behavior of ground-supported circular reinforced concrete tanks

Abstract

This study aims to investigate the effect of various parameters on the seismic behavior of concrete tanks. A finite element method using pushover and time-history analysis is developed to investigate the seismic behavior of circular ground-supported tanks. The response modification factor (R) is evaluated based on nonlinear static and time-history analyses. R-factor is one of the key parameters in seismic design. In liquid containing structures, R-factor in current codes and standards are based on empirical values. Therefore, a justifiable guideline to accurately determine these values is yet to be developed. This study shows that the effect of tank size, material non-linearity, base condition, and earthquake frequency is significant. Also, fixed based and shallow tanks have higher R values compared to hinged based and tall tanks, respectively. Based on the results of this study, it is found that the value of R specified in current practice is not appropriate.