Home News Industry Updates MBIE looks to revamp Standards and ban pigtail loops   

November 2017

MBIE looks to revamp Standards and ban pigtail loops   

18 Oct 2017, Industry Updates, Technical

Proposals from the Ministry of Business, Innovation and Employment (MBIE) to change aspects of design and construction in relation to concrete and steel structures have been met with industry approval

 As part of its response to recommendations arising from the investigation into the performance of Statistics House in 2016 Hurunui/Kaikōura earthquakes and also due to recommendations made by the Canterbury Earthquakes Royal Commission, MBIE has proposed a number of amendments to the way concrete and steel structures are constructed and designed.

The proposal includes updating Verification Method B1/VM1 to cite changes made to NZS 3101:2006 Concrete Structures Standard and NZS 3404 Steel Structures Standard.

Rob Gaimster, Chief executive of Concrete NZ – an industry body recently formed through the amalgamation of six industry associations –  said that overall his organisation is “quite happy” with the proposals.

“We welcome MBIE inviting consultation on its proposals and overall we’re supportive of the recommendations, particularly with regards to NZS 3101,” said Rob.

Pulling pigtails

An example of the pigtail, or loop bar connection that MBIE is seeking to ban

 MBIE propose a ban on the use of ‘pigtail loops’ in pre-cast flooring. Loop bar connections, known colloquially as ‘pigtail loops’, are used in commercial construction to support pre-cast concrete flange-hung double-tee flooring units. However, Rob says that his association’s members have not used the method since 2010 because more efficient methods became available.

“It is a specific detail for a precast system and our members have replaced it with more sophisticated methods; however, I can’t vouch for what people who aren’t part of our organisation are doing.”

MBIE has proposed the ban after an expert panel found it was a contributing factor in the collapse of some floor units in buildings affected by the Kaikoura earthquake. If issued, the ban is expected to come into force at the start of February 2018. The ban applies to consents issued from that date.

This is the second ban issued by MBIE who are at pains to point out the ban would not apply to building consents specifying pigtail loops which were issued before the ban came into effect. In that case MBIE advise the Council can’t require a change of product or method during construction and a code compliance certificate would be issued provided the building had been “built to consent” and all other necessary requirements were met.

Proposed changes to B1/VM1

B1/VM1, which cites NZS 3101:2006: Concrete Structures Standard and NZS 3404:1997: Steel Structures Standard, is a Verification Method for structural building design.

A Verification Method is not mandatory to use, but if followed, it provides a means of compliance for the building design. This makes the aforementioned standards part of an approved means to comply with the Building Code.

The latest version of NZS 3101:2006 addressed industry concerns over the potential earthquake performance of pre-cast concrete floor systems observed in the 2010 and 2011 Canterbury earthquakes and the more recent 2016 Kaikōura earthquakes.

The proposed modifications to NZS 3404:1997 in B1/VM1 would update the Verification Method to be in line with the standards and practices currently used in the steel industry, and relate to:

  • Correcting references to Standards that cited in NZS 3404.
  • Updating references for nuts, bolts and washers.
  • Steel fabrication.
  • Steel erection.
  • Modification of existing structures.
  • Architecturally exposed structural steel.

Parties affected by the proposals have until 5pm on 20 November to have their say on the proposed changes. For more information and submission forms, click here.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


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