Our industry’s decision to harmonize bridge design with Australia has seen us travel a five year road, and we’re delighted to see it all come together as we announce the availability for public comment of the first joint New Zealand and Australian design standard for steel and composite bridges DR AS/NZS 5100.6.

Chaired by our General Manager Structural Systems Dr Stephen Hicks, DR AS/NZS 5100.6 provides greater alignment with international best practice and in some cases significant improvements for our members involved in bridge infrastructure projects.

We see this collaboration as a way to increase our trade flows with Australia and creating more cost-efficient bridge designs that lead to market share growth and work opportunities for members.


Building bridges instead of walls

Following international trends that call for using less natural resources, higher strength concrete with compressive strengths up to 100 MPa, and quenched and tempered steels with a yield strength of up to 690 MPa – it was clear our existing standards had to react.

These higher strength materials went beyond the limits permitted in current international design standards, requiring many of the design provisions to be reassessed through structural reliability analyses to ensure the required margins of safety were maintained.

Since 2011, we’ve worked extensively with the University of New South Wales to evaluate these aspects, along with the University of Applied Sciences in Germany to implement a simplified damage equivalent factor format within the fatigue design provisions to DR AS/NZS 5100.6.

This has also been informed by the latest thinking from IIW, incorporating fabrication requirements to achieve a particular detail category. It’s hoped our findings will ensure the damage equivalent factor format is more easily implemented by our engineers to enable more efficient bridge designs for their clients.

Controversially, the continued inclusion of Appendix K to recognise steel currently permitted in New Zealand steel structures standard NZS 3404 manufactured to European and Japanese product standards is likely to raise some heads. As a consequence, we’d be grateful for your feedback on whether you support its inclusion or not.


What now?

So far, we’ve seen this work become a catalyst for further joint Australian-New Zealand design standards for steel construction with the development of AS/NZS 2327 for steel and concrete composite buildings, and in the future potentially AS4100 and NZS 3404 as well.

If you’d like to have your say during the public comment period ending 7 September 2016, you can download your copy of DR AS/NZS 5100.6 from Standards New Zealand here.

Our Structural Systems General Manager Dr Stephen Hicks is also happy to answer any questions directly