Dynamic buckling of steel tanks under seismic excitation: Numerical evaluation of code provisions

Many above-ground steel liquid storage tanks have suffered significant damages during past earthquakes. Such failures are due to several causes. The most common one is dynamic buckling. Several theoretical and experimental research studies were performed without solving this complex problem completely. Design codes such as AWWA-D100 and EC8 based their seismic standards on the recommendations given by some of these research results. The present contribution tries to evaluate these recommendations by using a numerical model with a robust and stable shell finite element. By using several seismic excitations and tanks with different geometrical parameter, this contribution tries to evaluate the PGA values that cause the tank instability. These numerical values are compared with standard code previsions. The obtained results confirm some code guidelines in the case of broad tanks, and show the need for improving them in the case of tall ones.