In-field dynamic response of instrumented wine tanks subjected to aftershock earthquakes

Abstract

An experimental investigation of the dynamic behaviour of anchored flat-based wine storage tanks in a winery located in Marlborough, New Zealand is presented herein. Six wine storage tanks with different dimensions, capacities, and anchorage systems were instrumented with accelerometers for approximately six weeks following the 2016 Kaikōura earthquake, providing an opportunity to conduct a parametric study of their dynamic response when subjected to 37 aftershock earthquakes. The largest accelerations measured in the horizontal (X and Y) and vertical (Z) axes directions at the top of the six tanks occurred in conjunction with a Mw5.48 aftershock earthquake, with analysis indicating that the peak acceleration at the tank top occurred along the horizontal (Y) axis with a value of 0.545 g.Analysis of accelerations recorded at the top of the six tanks revealed that for low-intensity earthquake shaking the largest accelerations were measured at the top of the 40kL tank. A comparison of the tank instrumentation data indicated that the 175kL tank with a shear bolt anchorage system performed better than the nominally identical 175kL tank with a necked tension anchorage system, with the maximum lateral accelerations attained in the horizontal X and Y axes directions for the tank with the necked tension anchorage system being on average 1.59 times and 1.39 times the acceleration attained for the tank with the shear bolt anchorage system. Analysis of the results for the highest intensity earthquake shaking (Mw5.48) also indicated that the two tanks with installed energy dissipation systems sustained less acceleration when compared to tanks with a traditional anchorage system. Also, good agreement was observed between the values of the impulsive period attained from the analysis of the tank instrumentation data and from finite element (FE) modal analysis.