This video from the 2022 NCC Seminars discusses Part H1D6 Framing from NCC 2022 Volume Two.
My name is Phil Finnimore I'm with the Australian Building Codes Board and today I'm going to talk about one part in
the framing section of Volume Two, which is relating to H1D6 structural steel members.
On the right hand side you'll see a Deemed-to-Satisfy solution that uses the
Nash Residential Suite of Standards AS 4100 or AS/NZS 4600, if you don't choose that
Deemed-to-Satisfy solution you can use the ABCB Housing Provisions for NCC 2022 specifically Part 6.3.
So looking at H1D6, starting at subclause (5). this is the link between
Volume Two and the Housing Provisions that are Part 6.3 relative to structural steel members.
if you choose this path, 6.3 will set our details and through the acceptable
construction practice review we'll talk about some of the technical changes, but
highlighting the connection between Volume Two and the Housing Provisions rest in H1D6 subclause (5).
Before we move on to that subclause (6), there's a note it's a new clause in subclause (f) and it says
the geometric limits set out in AS 4055 clause 1.2 need to be observed. If you're going to use
the Housing Provisions the design of the building that you're using will have to be within the limit
set out in this particular standard. And in summary Clause 1.2 of 4055 that's the wind load for houses
is setting out geometric limits relating to: the height of eaves, the maximum height
the width of the building including verandas and excluding ease and also the maximum roof pitch.
So if you're within those limits you can still continue to use the Housing Provisions for 2022.
One of the things the acceptable construction practice review required
or desired to have clarified was referenced to the first dimension of steel. It currently exists
in 2019 but it's a bit vague in its application, so what we've done is set out some examples in here
to say that the first dimension of steel to be installed vertically refers to the larger of the
two dimensions of a particular steel member. In this case a 150 by 90 by 8 unequal angle,
the larger dimension there of 150 is the first dimension of steel that needs to be installed vertically.
So we provided that clarification to say the installation of the first dimension of
steel vertically will always refer to the larger of the dimensions of a particular steel element.
There's an example of on the left the correct way of doing it the 150 is the vertical dimension
because it's greater than 90. It is not acceptable acceptable to use that particular dimension
horizontally, it will not comply with the first dimension of steel being installed vertically.
Structural steel members a comparison between 2019 Volume Two and Part 6.3 in
the Housing Provisions, as set out there. What we've done is
more clearly articulated separate parts for different structural steel members
6.3.2 structural steel members overall and then we go into: bearers, strutting beams, lintels, columns,
all the way through to corrosion protection which is an existing set of tables in 2019.
Part 6.3.7 right through to 6.3.9 we've added some new requirements and details about fixing
and bearing provisions and also allowances and tolerable limits for penetrations, we'll also
talk about corrosion protections and in particular how we've explained the use of 2019 provisions for
a period of 12 months. Part 6.3 in the Housing Provisions there's one important thing to note
and that is there in 6.3.2 subclause (2) there is a requirement for structural steel members
to have a minimum nominal yield strength of 250 MPa. Structural standards require a minimum yield
strength of steel and in particular in Australia we want to make sure the best quality steel is
being used so we spelled out clearly in the Housing Provisions a minimum yield
strength of 250 MPa for any of the structural steel members set out in 6.3.2(1) (a) (b) and (c).
Having a look at some tables and this has just been put in as an example the tables
have changed a little bit from 2019 to 2022, the information is largely the same but the format
will be slightly different. The table notes in this case we've got bearer supporting tiled floors, the
table notes are more aligned with structural designs so they complement the information
and the data in the tables and they've been set out in a way that supports our digital format.
Some details about cutting and truncations and structural steel members there are clauses that
are relevant to these particular details we put these in there to
graphically illustrate what we're talking about. There's a need to set out dimensions
maximums and minimums in terms of cutting. If you're looking at the diagram on the left
to maintain structural reliability we've got maximum truncation sizes and depths for
particular beams in this case a strutting beam we've also got a detail on the right
there that sets out timber connections to steel beams, for things such as roofs and
floors to be supported, including the size of bolts and their maximum centers for connection.
We've also included details and these are not the only details we do have more this is just
an example but the connection of steel beams to columns and the need for particular thicknesses
of plates, dimensions of plates, connections, bolt sizes and bolt dimensions. We've got base plate
connections to steel columns, there are more details in the code this is just an example
to use. We've also got details in explanatory information about the bearing capacities for
different types of structural steel members onto columns and we've also set out some
allowable zones and prohibited zones for the penetration through structural steel members
for various services, be they plumbing, air conditioning or whatever the case may be.
Corrosion protection an important thing to note is that for the tables in NCC 2022 we've set out
a set of different and new solutions for corrosion protection, they are quite different to the current
provisions in the tables for corrosion protection in 2019, but if you have a look at the bottom of
this table we've provided a note there to say for a period of 12 months from the adoption of
NCC 2022 you can still use the provisions that exist in 2019. So in summary from adoption date
you have 12 months that you can still use the 2019 corrosion protection table requirements.