Seismic Analysis of RC Clinker Silos

This research addresses the nonlinear analysis of flat bottom clinker silos that are typically used to store granular materials. Most of silos’ failure is due to the inefficiency to resist seismic forces. One of the silo failure reasons is that filled granular material is usually treated as a water pressure which is not realistic. Water pressure is linearly distributed, while granular material has a nonlinear distribution along silo height. The main investigated variables were silo width, height, reinforcement ratio, and the existence of opening in the bottom part of the silo wall. Effects of these variables on silos’ dynamic properties - modal periods and mode shapes - as well as seismic response, base shear, base overturning moment, and the least number of modes needed to satisfy mass participation of 90%, were examined. Extensive numerical analyses were conducted to examine these parameters using different types of analyses such as free vibration, response spectrum, and pushover analysis. It was found that increasing height on time-period has a great effect when compared to the effect of diameter increase. Reinforcement ratio in silo without openings has a minor effect in small diameters while it has a major effect in case of silos with large diameters.