Retrofitting of a damaged liquid storage tank using steel and SMA anchor bolts

Abstract

The inappropriate performance of liquid storage tanks following devastating earthquakes indicates that the tank damage could lead to catastrophic consequences. As the rocking response of unanchored tanks plays a significant role in their seismic performances, the base anchorage is an essential element to control the seismic performance of on-ground tanks. The present study focuses on the effect of anchorage systems, as the retrofitting strategy, on the seismic performance of an existing unanchored tank damaged during the Silakhor Earthquake of 2006 in Iran. To this end, regular steel and shape memory alloy (SMA) anchor bolts were utilized. The Seismic performance of the tank was evaluated before and after retrofitting. For every retrofitted tank, different configurations of anchor bolts were considered. The seismic performance of tanks has been investigated using incremental dynamic analysis (IDA) analysis. To assess the seismic performance of every case, a fragility analysis was conducted. The results revealed that anchored tanks showed better seismic performance compared to unanchored ones. It was also shown that the combination of energy dissipation and the super-elastic behavior of SMA anchors leads to a considerable reduction in shell failure and damage to the anchorage system.