Recommendations of a NZSEE Study Group on Seismic
Design of Storage Tanks
The
Recommendation for the Seismic Design of Storage Tanks
provides guidance on the particular dynamic load effects during
an earthquake of liquids stored in various forms of containment
systems, or tanks. Structural analysis and design criteria for
tanks constructed from steel, reinforced concrete and other
materials are covered by the recommendations. Tank foundation
investigation, evaluation, analysis and details are considered.
A wide range of issues to do with the design detail are
reviewed and covered by commentary, and the document contains
design charts and design examples. The recommendations were
first published in 1986 and have been widely used in New
Zealand as well as acknowledged internationally.
Since 1986, there have been
substantial changes to the regulatory environment and
applicable standards in New Zealand. Therefore, to meet current
requirements the principal changes in this revised document
are:
- Seismic load is derived from the current national standard
for derivation of seismic loads for buildings in New Zealand,
NZS 1170.5.
- A procedure is presented to allow assessment of an
appropriate return period factor, Ru.
- A correction factor based on the ductility and damping
applicable to tank behaviour is applied.
- Some limited ductility is permitted in steel tanks on grade.
This generally reduces the load demands from those given
previously.
- The document is presented in a form that can be interfaced
with other international design codes.
The Recommendations are currently under review by ERMA to determine the document’s compliance with the New Zealand HSNO Act. With approval of the Recommendations as a Code of Practice, a notice and any required amendments will be circulated to previous purchases of the Recommendations. All subsequent copies of the Recommendations will have the approval and any amendments incorporated into the document. Copies of the November 2009 Recommendations can be purchased from the Executive Officer of NZSEE by sending your request to exec@nzsee.org.nz Please provide name and postal address.