The Structural Engineer's Corner

Eng. Onorio Francesco Salvatore

[DOWNLOAD] Annual Probability of Exceedance for structures in New Zealand according to AS-NZS 1170

Written By: Lexatus - Nov• 17•13

Return Period 4 - Onorio

In this post an Excel spreadsheet based on the AS/NZS 1170 is available. Scope of the tool is to define the Annual Probability of Exceedance, P (and, hence, Average Recurrence Level, R), for Ultimate State Limit and Serviceability Limit States. The values are referred to New Zealand, as per Section 3, Table 3.3.

The Annual Probability of Exceedance is the probability that a given event over a given duration will be exceeded in any one year; it is the inverse of the Return Period, also know as Recurrence Interval.

The Return Period/Recurrence Interval is an estimate of the likelihood of an event, such as an earthquake. It is a statistical measurement based on historic data denoting the average recurrence interval over an extended period of time. Any times a Structural Engineer refers to return periods for the evaluation of an action, he is basically doing a risk analysis. Hence, it is used to design structures to withstand an event with a certain return period.

These parameter are based on the following inputs, according to AS/NZS 1170:

Design working life (temporary, less than 6 months, 5 years or less, 25 years, 50 years, 100 years or more);

Type of structure (minor, normal, major, post-disaster, exceptional);

Type of analysis (ULS, SLS 1, SLS 2).

Return Period 1 - Onorio


Return Period 2 - Onorio

You can download the Excel spread sheet from here:

Download at just € 0.99



For any issues or questions, you can contact the author at:

Eng. Onorio Francesco Salvatore

You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.


  1. Web design says:

    It is only in this way can any graphic designing company helps to serve you better.
    The first table may consist of your logo and any header information that you wish
    to include in your web design. Add testimonials or evaluations
    to your landing page.

  2. Some truly great information, Gladiola I detected this. “So long as little children are allowed to suffer, there is no true love in this world.” by Isodore Duncan.

  3. Why users still use to read news papers when in this technological world all is accessible
    on web?

Leave a Reply

Your email address will not be published. Required fields are marked *