Paper Number 04 Revised NZSEE Recommendations for Seismic Design of Storage Tanks

Conference ABSTRACT: The 1986 NZSEE document Recommendations for Seismic Design of Storage Tanks has been updated and will be republished during 2008. The original publication has been widely used and acknowledged internationally. Since 1986 there have been substantial changes to legislation and applicable standards in New Zealand and internationally. The design basis used in the 1986 document assumed no yield or damage being permitted to tanks under the design earthquake loading, and therefore led to some conservatism in the design of large steel storage tanks. The 2008 document bases design seismic loads for tanks on the recently issued national Standard for loads for buildings in New Zealand, NZS 1170.5. Design seismic loads are based on the ductility and damping applicable to tank behaviour. Modest levels of ductility (or force reduction) are permitted for steel tanks on grade, which generally reduces the load demands from those given previously. Benchmarking comparisons of the revised approach against the previous document and other relevant codes suggest that the proposed approach is reasonable. NZSEE is aiming to have this document recognised as a code of practice in New Zealand. The document has been structured in a way that it could also be used with other international codes