The Seismic Fragility Curve of Atmospheric Steel Storage Tanks on a Pile

Abstract

Fluid storage tanks, especially above ground tanks, are categorized as important and essential in energy infrastructure. These storages, which are mostly used to store petroleum fluids and fire water supplies, are therefore of great importance to the exploitation of tanks after the earthquakes. Fragility or vulnerability curve is one of the most effective tools for estimating the damage caused by the earthquake. Preparing the seismic fragility curve of above ground tanks on a pile is the aim of this research. This fragility curve is achieved regardless of tank body damage and only by focusing on the structural behavior of the foundation. These tank types are primarily built on low load bearing areas. In this study, three tank types that have been designed in accordance with API650-13 have been investigated in a practical project. For this purpose, using the static nonlinear analysis method, the structural capacitance curve of tanks was first obtained. Then, the seismic performance of these tanks was obtained for 12 spectra from different records with different accelerations. After calculating the damage indexes on the structure, the appropriate statistical distribution for the failure criteria was chosen. Finally, the calculation of the probability of failure for the fracture curve of the required tanks was obtained Fluid storage tanks, especially above ground tanks, are categorized as important and essential in energy infrastructure. These storages, which are mostly used to store petroleum fluids and fire water supplies, are therefore of great importance to the exploitation of tanks after the earthquakes. Fragility or vulnerability curve is one of the most effective tools for estimating the damage caused by the earthquake. Preparing the seismic fragility curve of above ground tanks on a pile is the aim of this research. This fragility curve is achieved regardless of tank body damage and only by focusing on the structural behavior of the foundation. These tank types are primarily built on low load bearing areas. In this study, three tank types that have been designed in accordance with API650-13 have been investigated in a practical project. For this purpose, using the static nonlinear analysis method, the structural capacitance curve of tanks was first obtained. Then, the seismic performance of these tanks was obtained for 12 spectra from different records with different accelerations. After calculating the damage indexes on the structure, the appropriate statistical distribution for the failure criteria was chosen. Finally, the calculation of the probability of failure for the fracture curve of the required tanks was obtained.

Keywords

• atmospheric steel storage tank
• fragility curve
• pile
• damage