NCC requirement for anchor connections

The 2016 edition of the National Construction Code (NCC) refers to SA TS 101: 2015 as “deemed-to-satisfy” in determining the structural resistance of an anchor connection in buildings.

SA TS 101: 2015 is a Standards Australia Technical Specification that covers minimum requirements for anchorage design and product prequalification. The provisions of SA TS 101 satisfy the performance-based requirements of the NCC.

NCC 2016 Vol 1 NCC 2016 Vol 2


The need for an anchor connection standard

Often, structural steel members are fastened to concrete by means of cast-in or post-installed anchors. AS 4100 and AS 3600 are well established standards for designing steel and concrete structures, respectively. Before the introduction of SA TS 101, there was no Australian Standard for concrete anchors that equally matches the level of technical detail offered by AS 4100 and AS 3600. For many years, engineers were left to decide what design model or standard to use for their anchor connections. In effect, foreign standards and/or published anchor product information becomes the major basis for the connection design. This clear need to enhance the safety standards in anchoring led to the formation of the Australian Engineered Fasteners and Anchors Council (AEFAC). AEFAC is an expert committee representing relevant organisations in the Australian fastener industry and is responsible for the instigation and development of the SA TS 101: 2015. Proudly, Hobson Engineering is one of the few Founding Members of AEFAC who saw the urgency to propose a standard that will give anchor connections, the same level of technical depth and importance as structural steel and concrete structures. More information is available in the AEFAC website: www.aefac.org.au

NCC 2016 Vol 1
 
 
Standards that refer to SA TS 101

Because of the relevance and safety benefits offered by SA TS 101, a number of other Standards have referred to it for the design and qualification of anchor connections. So far, they are as follows:
  • National Construction Code 2016: Volumes 1 and 2
  • AS 5131: 2016 - Structural steelwork—Fabrication and Erection
  • NASH 2014 Standard
 
Scope of the SA TS 101: 2015

SA TS 101: 2015 is based on European Standards for anchorage design and product prequalification. The scope of this new standard can be broken down into two categories:

1. Anchor type
  • Post-Installed mechanical anchors
  • Post-Installed chemical anchors
  • Cast-in channels with rigid connections

2. Application type
  • Safety critical anchor connections to concrete. The term ‘safety-critical’ denotes a risk to the welfare of people or considerable economic loss in the event of failure. The responsible engineer will determine whether a certain anchor application is safety-critical.
  • Anchoring in normal weight concrete with compressive strength ranging from 12MPa to 90MPa or as prescribed in the anchor product’s assessment.
  • Anchor applications where loadings are static and quasi-static which may include tension, shear, bending or torsion moments, or a combination thereof.

In addition, SA TS 101 can be only directly used to a specific anchor arrangement and does not cover the following:
  • Design of fastenings/anchorages that are exposured to fire, durability and seismic actions
  • Design of fastenings/anchorages for lifting, transport and erection (e.g. brace inserts, lifting inserts, etc.), headed fasteners, ferrules, reinforcement for development length considerations, headed reinforcement and anchorage for prestressing strands.
Anchors that are compatible with
SA TS 101

Anchor products that were pre-qualified in accordance with SA TS 101 Appendix B or anchor products that have existing European Technical Approvals/Assessments (ETA) can be used directly with SA TS 101.

There are different paths for compliance with the performance requirements of the National Construction Code (NCC) and using SA TS 101: 2015 is one of them.
Hobson Engineering and SA TS 101

Even before SA TS 101: 2015, Hobson Engineering has been supplying mechanical and chemical anchor products that have ETAs, specifically for customers that require anchor products that have the required approvals. This is to say that all of the MKT® products with ETA that we carry conform to the requirements of SA TS 101 Appendix B. Our anchor product portfolio remains strong and ready for the changes in our anchor industry, as a result of the new NCC requirements. All anchor approvals and product sheets can be easily downloaded from our website. To see which MKT® products are compatible with SA TS 101, please click here.

To complement the MKT® anchor product range, Hobson Engineering offers another group of anchors - we call them the Conxtruct® range - that are for applications not requiring detailed assessment information such as those found in an ETA. For a list of our Conxtruct® anchors, please click here.

The revised NCC and SA TS 101: 2015 further uplifts the level of safety and security in Australian structures, and that is good. We at Hobson Engineering are ready and committed in giving you the commercial and technical support needed to help promote the positive changes that this new standard will bring. As a start, you may want to click the following links:

European Technical Assessment/Approval (ETA) for MKT® products
Conxtruct® Data Sheets

Frequently Asked Questions (FAQ) about SA TS 101 and NCC

Q: Where may I get a copy of SA TS 101?
A: SA TS 101 is a Standards Australia document that is published by SAI Global. The complete reference is: Standards Australia Technical Specification 101:2015 “Design of post-installed and cast-in fastenings for use in concrete”

Q: What types of anchors need to be designed according to SA TS 101?
A:The scope of SA TS 101 is limited to the design of fastenings to concrete in safety-critical applications. The scope of fasteners includes post-installed (mechanical and chemical) and cast-in anchor channel. In order for a fastener to be designed according to SA TS 101 it must first have been tested and assessed (prequalified) in accordance with SA TS 101 Appendix B.

Q: How do I know if a fastener complies with SA TS 101?
A: Anchor products that were pre-qualified in accordance with SA TS 101 Appendix B or anchor products that have existing European Technical Approvals/Assessments (ETA) can be used directly with SA TS 101.

Q: As an NCC referenced document, when does SA TS 101 come into effect?
A: The 2016 NCC came into effect on 1st May, 2016.

Q: What are safety-critical fasteners?
A: The term ‘safety-critical’ denotes a risk to the welfare of people or considerable economic loss in the event of failure. In the case of fasteners the responsible engineer will determine whether a certain application is safety-critical.

Q: What types of concrete is SA TS 101 applicable to?
A: SA TS 101 is applicable only to normal-class concrete (according to AS 1379) within a compressive strength range of 12 – 90 MPa determined via cylinder tests and a minimum age of 28 days. For the purpose of design, f’c < 60 MPa. SA TS 101 does not currently cover the performance of fasteners in concrete that includes cement substitutes (i.e. geopolymers) or reinforcement other than deformed bars (e.g. steel fibre). Full details are provided in SA TS 101:2015 Cl. 2.5.

Q: What is cracked concrete?
A: The condition of the concrete – cracked or uncracked – has implications on the selection of a suitable fastener as well as fastener design. For the purpose of fastener design, cracked concrete is any concrete whose tensile strength may be exceeded at any time after the fastener has been installed, resulting in a crack that may pass through the plane of the fastener. Cracks may develop due to multiple factors such as the discontinuity introduced due to drilling, hoop stresses developed by the fastener due to installation (e.g. expansion fasteners) and loading, as well as other factors.

Q: Can any anchor to concrete be designed using SA TS 101?
A: No. The scope of SA TS 101 covers mechanical and chemical post-installed anchors as well as cast-in anchor channel. Additionally, in order to be compatible with the design provisions of SA TS 101, the anchors must first be prequalified in accordance with SA TS 101 Appendix B. A specific testing and assessment procedure must be followed in order to develop the appropriate parameters for use in the design equations. Products that have a current European Technical Assessment/Approval (ETA) are compatible with SA TS 101 via minor amendment to notation outlined in SA TS 101 Appendix C.

Q: What is the difference between a fastener and an anchor?
A: These two terms are frequently used to describe the same thing: a device connecting an element to concrete. In Australian practice a fastener installed in concrete may be referred to as an ‘anchor’, such as ‘mechanical anchor’ and ‘chemical anchor’.

Reference
www.aefac.org.au