Revised steel structures standard published

Standards New Zealand Media Release
12 October 2009

Part 1 of the revised steel structures Standard published

Standards New Zealand has just published Steel structures Standard – Part 1: Materials, fabrication, and construction (NZS 3404.1:2009) which will supersede in part NZS 3404 Parts 1 and 2:1997 including Amendment No. 1 and No. 2 (NZS 3404:1997).

NZS 3404.1:2009 is the first part to be released in the new steel structures Standard suite.

NZS 3404:1997 has been reviewed because of the increasing use of steel structures and changes to the regulatory framework. The steel structures Standard will now include a suite of seven parts that are grouped into general topics. This framework is more beneficial to users of the Standard who may not need all parts, such as fabricators and constructors who don’t need the design provisions. The seven parts cover:

• materials, fabrication, and construction

• structural analysis

• general design of members and connections

• design of composite members

• design for fire

• design for fatigue

• design for earthquakes.

‘Splitting the steel structures Standard into seven parts is a very good idea,’ says Dr G Charles Clifton, development committee member and 2008 Standards New Zealand Meritorious Award Winner. ‘Some of the new parts will provide a compliance document in an area where there is currently no compliance document. For example, Part 5 ‘design for fire’ will include a comprehensive design process for different applications for fire. That is missing from the 1997 edition of the steel structures Standard and there is currently no guidance of the scope proposed in Part 5, anywhere else, worldwide.’

Materials, fabrication, and construction requirements in Part 1

NZS 3404.1:2009 brings all the construction and fabrication material into a stand-alone document for users. ‘There was a real need to incorporate feedback from users, clarify good practice, and provide a body of commonly accepted knowledge,’ says committee Chair Clark Hyland.

Part 1 sets out minimum requirements for the selection of materials, corrosion protection systems, and the fabrication, erection, and construction of steel structures. It applies to building structures, crane support girders, highway, railway, and pedestrian bridges, and composite steel and concrete beams and columns.

Users of Part 1 include architects, builders, building control authorities, building inspectors, coatings applicators, fabricators, regulators, steel distributors, steel constructors, and structural engineers.

‘Fabricators and material suppliers won’t need to buy the design sections, which they don’t need to use,’ says Charles. ‘In addition, the provisions in Part 1 for durability will be very beneficial for architects. The Standard includes clearer information on tolerances, corrosion, and architectural finishes. Architects often are responsible for specifying coatings to steelwork and these provisions will give them much more accurate surface-specific corrosivity and the correct coating to be applied to that surface.’

Part 1 in practice

NZS 3404.1:2009 supersedes the relevant provisions in NZS 3404:1997 and will be referenced by Parts 2 to 7 once those parts are complete.

• NZS 3404:1997 will not be withdrawn until the full steel structures Standard suite is published.

• To assist users of NZS 3404:1997, NZS 3404.1:2009 includes an appendix that clearly outlines the clauses, figures, tables, and related commentary from the 1997 version, which are superseded by NZS 3404.1:2009. Users of NZS 3404:1997 should refer to this appendix in Part 1 to understand the new requirements for materials, fabrication, and construction.

• This identification allows the remaining clauses of NZS 3404:1997 to be used in conjunction with the provisions of NZS 3404.1:2009.

It is intended that once all parts of the revised steel structures Standard (that is, NZS 3404.1 to NZS 3404.7) are published, NZS 3404.1:2009 will be referenced in the Compliance Document for the New Zealand Building Code Clause B1 Structure, Verification Method B1/VM1, and Clause D2 Durability, Acceptable Solution D2/AS1.

Knowledge of the content of NZS 3404.1:2009 will be one of the indicators of competency for steel structures licensed building practitioners (LBP), for which restricted work requirements will commence in 2012.

Significant new provisions in Part 1

In addition to reformatting the Standard, significant new provisions have been added as follows:

• specific guidance for identifying corrosivity of steelwork and selection of protective coatings in the New Zealand environment (complementing the coatings standard AS/NZS 2312)

• a means of categorising the finishing requirements of architecturally exposed structural steel (AESS)

• the extent of weld testing is now more consistently and easily determined by use of a loadings demand, and consequence of weld failure assessment approach

• seismic grade steel types 2S and 5S have been introduced following on from the performance specification requirements set in Amendment 2 of the 1997 edition and, in line with subsequent changes to AS/NZS 3679.1 and AS/NZS 1554

• clarification and expansion of tolerances, which are up to date with international Standards

• construction provisions for composite construction are now clearly stated in Part 1 and will be read by those responsible for construction, and implemented. This will allow users to do a complying design, rather than an alternative design, and will ease the process of progressing the design through the building control system

• special provisions for highway bridges and railway bridges have been significantly updated and specific requirements for bridges have been added, which were not covered in the existing Standard.

The committee included representatives of the following nominating organisations: Association of Consulting Engineers New Zealand, Cement and Concrete Association of New Zealand, Department of Building and Housing, Institution of Professional Engineers New Zealand, New Zealand Heavy Engineering Research Association, Steel Construction New Zealand, Structural Engineering Society New Zealand, University of Auckland, and University of Canterbury.

The Department of Building and Housing sponsored the review.

Steel structures Standard – Part 1: Materials, fabrication, and construction NZS 3404.1:2009 is available in two forms:

• Hardcopy with a binder, or

• As loose-leaf or a downloadable PDF.

Visit www.standards.co.nz (keyword 3404), email enquiries@standards.co.nz, or call customer services on 0800 782 632.

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