2022 NCC Seminars: Volume Two - Framing

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[Music]  

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My name is Phil Finnimore I'm with the Australian Building Codes Board  and today I'm going to talk about one part in  

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the framing section of Volume Two, which is  relating to H1D6 structural steel members.

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On the right hand side you'll see a Deemed-to-Satisfy solution that uses the  

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Nash Residential Suite of Standards AS 4100 or  AS/NZS 4600, if you don't choose that

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Deemed-to-Satisfy solution you can use the ABCB Housing  Provisions for NCC 2022 specifically Part 6.3.

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So looking at H1D6, starting at subclause (5). this is the link between  

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Volume Two and the Housing Provisions that are  Part 6.3 relative to structural steel members.

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if you choose this path, 6.3 will set  our details and through the acceptable  

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construction practice review we'll talk  about some of the technical changes, but  

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highlighting the connection between Volume Two and  the Housing Provisions rest in H1D6 subclause (5).  

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Before we move on to that subclause (6), there's a  note it's a new clause in subclause (f) and it says  

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the geometric limits set out in AS 4055 clause  1.2 need to be observed. If you're going to use  

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the Housing Provisions the design of the building  that you're using will have to be within the limit  

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set out in this particular standard. And in summary  Clause 1.2 of 4055 that's the wind load for houses  

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is setting out geometric limits relating  to: the height of eaves, the maximum height  

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the width of the building including verandas and  excluding ease and also the maximum roof pitch.

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So if you're within those limits you can still  continue to use the Housing Provisions for 2022.  

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One of the things the acceptable  construction practice review required  

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or desired to have clarified was referenced to  the first dimension of steel. It currently exists  

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in 2019 but it's a bit vague in its application, so  what we've done is set out some examples in here  

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to say that the first dimension of steel to be  installed vertically refers to the larger of the  

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two dimensions of a particular steel member. In this case a 150 by 90 by 8 unequal angle,

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the larger dimension there of 150 is the first  dimension of steel that needs to be installed vertically.

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So we provided that clarification to  say the installation of the first dimension of  

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steel vertically will always refer to the larger  of the dimensions of a particular steel element.

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There's an example of on the left the correct  way of doing it the 150 is the vertical dimension  

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because it's greater than 90. It is not acceptable  acceptable to use that particular dimension  

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horizontally, it will not comply with the first  dimension of steel being installed vertically.

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Structural steel members a comparison  between 2019 Volume Two and Part 6.3 in  

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the Housing Provisions, as set  out there. What we've done is  

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more clearly articulated separate parts  for different structural steel members  

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6.3.2 structural steel members overall and then  we go into: bearers, strutting beams, lintels, columns,

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all the way through to corrosion protection  which is an existing set of tables in 2019.

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Part 6.3.7 right through to 6.3.9 we've added  some new requirements and details about fixing  

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and bearing provisions and also allowances and  tolerable limits for penetrations, we'll also  

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talk about corrosion protections and in particular  how we've explained the use of 2019 provisions for  

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a period of 12 months. Part 6.3 in the Housing  Provisions there's one important thing to note  

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and that is there in 6.3.2 subclause (2) there  is a requirement for structural steel members  

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to have a minimum nominal yield strength of 250  MPa. Structural standards require a minimum yield  

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strength of steel and in particular in Australia  we want to make sure the best quality steel is  

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being used so we spelled out clearly in  the Housing Provisions a minimum yield  

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strength of 250 MPa for any of the structural  steel members set out in 6.3.2(1) (a) (b) and (c).

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Having a look at some tables and this has  just been put in as an example the tables  

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have changed a little bit from 2019 to 2022, the  information is largely the same but the format  

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will be slightly different. The table notes in this  case we've got bearer supporting tiled floors, the  

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table notes are more aligned with structural  designs so they complement the information  

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and the data in the tables and they've been set  out in a way that supports our digital format.

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Some details about cutting and truncations and  structural steel members there are clauses that  

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are relevant to these particular  details we put these in there to  

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graphically illustrate what we're talking  about. There's a need to set out dimensions  

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maximums and minimums in terms of cutting. If you're looking at the diagram on the left  

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to maintain structural reliability we've  got maximum truncation sizes and depths for  

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particular beams in this case a strutting  beam we've also got a detail on the right  

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there that sets out timber connections to  steel beams, for things such as roofs and  

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floors to be supported, including the size of  bolts and their maximum centers for connection.

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We've also included details and these are not  the only details we do have more this is just  

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an example but the connection of steel beams to  columns and the need for particular thicknesses  

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of plates, dimensions of plates, connections, bolt  sizes and bolt dimensions. We've got base plate  

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connections to steel columns, there are more  details in the code this is just an example  

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to use. We've also got details in explanatory  information about the bearing capacities for  

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different types of structural steel members  onto columns and we've also set out some  

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allowable zones and prohibited zones for the  penetration through structural steel members  

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for various services, be they plumbing, air  conditioning or whatever the case may be.

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Corrosion protection an important thing to note  is that for the tables in NCC 2022 we've set out  

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a set of different and new solutions for corrosion  protection, they are quite different to the current  

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provisions in the tables for corrosion protection  in 2019, but if you have a look at the bottom of  

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this table we've provided a note there to say  for a period of 12 months from the adoption of  

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NCC 2022 you can still use the provisions that  exist in 2019. So in summary from adoption date  

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you have 12 months that you can still use the  2019 corrosion protection table requirements.