Verification Method B1/VM1

The first Verification Method for clause B1 Structure is known as Verification Method B1/VM1 or simply B1/VM1. It cites several New Zealand and Australia/New Zealand standards as a means to design structures that meet the seismic performance requirements of the Building Code. For any particular building, Verification Method B1/VM1 generally consists of AS/NZS 1170 Structural design actions and a compatible design standard for each specific material (concrete, steel, etc). In some cases, these may be modified slightly by the Verification Method.

Most structures designed using a specific design process follow Verification Method B1/VM1.

The standards and other documents referenced (in whole or in part) by B1/VM1 1st edition amendment 20 (effective 29 November 2021) are:

    • AS/NZS 1163:2016 Cold-formed structural steel hollow sections
    • AS/NZS 1170 Structural design actions Parts 0, 1, 2 and 3
    • NZS 1170.5:2004 Structural design actions – Part 5: Earthquake actions – New Zealand
    • AS/NZS 1554.1:2014 Structural steel welding – Part 1: Welding of steel structures
    • AS/NZS 1594:2002 Hot-rolled steel flat products
    • AS/NZS 1664.1:1997 Aluminium structures – Limit state design
    • AS/NZS 1748.1:2011 Timber – Solid – Stress graded for structural purposes Parts 1 and 2
    • AS/NZS 2327:2017 Composite structures – Composite steel-concrete construction in buildings
    • NZS 3101.1:2006 Concrete structures standard – Part 1: The design of concrete structures
    • NZS 3106:2009 Design of concrete structures for the storage of liquids
    • NZS 3404.1:1997 Steel structures standard
    • SNZ TS 3404:2018 Durability requirements for steel structures and components
    • NZS 3603:1993 Timber structures standard
    • NZS 3622:2004 Verification of timber properties
    • AS/NZS 3678:2016 Structural steel – Hot-rolled plates, floorplates and slabs
    • AS/NZS 3679:2016 Structural steel Parts 1 and 2
    • AS/NZS 3725:2007 Design for installation of buried concrete pipes
    • AS/NZS 4058: 2007 Precast concrete pipes (pressure and non-pressure)
    • NZS 4211:2008 Specification for performance of windows
    • NZS 4219:2009 Seismic performance of engineering systems in buildings
    • NZS 4230:2004 Design of reinforced concrete masonry structures
    • NZS 4297:1998 Engineering design of earth buildings
    • NZS 4402 Methods of testing soils for civil engineering purposes
    • NZS 4431:1989 Code of practice for earth fill for residential development
    • AS/NZS 4600:2005 Cold-formed steel structures
    • AS/NZS 5131:2016 Structural steelwork – Fabrication and erection
    • SNZ HB 8630:2004 Tracks and outdoor visitor structures
    • BS EN 14399 High-strength structural bolting assemblies for preloading Parts 1, 2, 3 and 5
    • AS 1391:2007 Metallic materials – Tensile testing at ambient temperature
    • New Zealand Geomechanics Society Guidelines for the field descriptions of soils and rocks in engineering use, Nov 1988
    • Chartered Professional Engineers of New Zealand Act 2002
    • ISO 15630-2:2010 Steel for the reinforcement and prestressing of concrete – Test Methods – Part 2: Welded fabric
    • ISO 17025:2005 General requirements for the competence of testing and calibration laboratories

With regards to earth fill, note that NZS 4431:1989 Code of practice for earth fill for residential development currently remains the standard deemed to comply with the Building Code. An updated version of this standard, NZS 4431:2022 Engineered fill construction for lightweight structures, was published in 2022. The updated standard can be used as part of an alternative solution to demonstrate Code compliance.

If a designer uses the Verification Method as the means of compliance, there are sometimes options available for seismic design of building elements. AS/NZS 1170 is the primary source for defining seismic design actions and design methods. The main material standards (concrete, steel, timber) provide design methods specific to those materials. Other standards within the Verification Method may provide seismic design actions and design methods to follow for some generic applications, such as engineering systems or fire protection. The designer can choose the option within the Verification Method that is most appropriate to their particular application.

AS/NZS 1170 Structural design actions

AS/NZS 1170 Structural design actions, which is actually a series of related documents collectively referred to as the loadings standard, consists of five parts covering a range of structural design issues. Each part was written at a different time. The most relevant to the design of seismically resilient buildings is NZS 1170.5:2004 Structural design actions – Part 5: Earthquake actions – New Zealand.

This part of the standard is highly technical. It is intended to provide methods for structural engineers to determine earthquake loading levels and specifications and to determine the seismic design loads and design methods for buildings and elements.

NZS 4219:2009 Seismic performance of engineering systems in buildings

NZS 4219:2009 Seismic performance of engineering systems in buildings sets out general objectives and seismic performance requirements for engineered systems related to the normal functioning of the building, in particular, building services. It covers the design, construction and installation of seismic restraints for these engineered systems.

NZS 4219:2009 covers components, such as boilers, that do not form part of the primary structure, but excludes contents or items that are not attached to the building structure, such as portable appliances and process plant. Such a large mass is very likely to alter the seismic response of the overall structure, invalidating assumptions about the building configuration made in the loading standard and making it necessary to carry out a special seismic analysis.