G'Day and welcome back to Buildsum and this is going to be a little bit of a
series on calculating wall bracing continuing on from my previous series on
on AS1684.2 the timber framing code for non-cyclonic
areas just kind of look more specifically at wall bracing and how you
calculate and work that out okay so obviously this is a comes from a s
AS1684.2 the timber framing code non-cyclonic it's a section
8 which is racking and shear forces bracing okay so the first paragraph says
that bracing has to be designed and provided for each story of the house and
the subfloor where required so you have a two-story house you have to design the
bottom floor and the second floor independently of each other it's
different requirements because of you know it's the second floor it's got more
wind exposure etc and also if you've got a subfloor for the houses up on piers
you have to design for that as well also as the wind can blow from any direction
the wind direction that results in the greatest loading shall be used so
basically the side of the house that presents the largest surface area facing
the wind we use that in our calculations and we generally we always calculate two
directions anyway so one blowing onto the front of the house and one blowing
onto the side of the house now if for some reason the front of your house
doesn't have much surface area and there's more white surface very at the
back then we reduce the back that's our biggest area and will give us our
biggest load so we always go with the largest surface area to work out our
loads just the note about temporary bracing temporary bracing is required to
support wind and construction loads on the building during construction
temporary bracing shall be the equivalent to at least sixty percent of
the permanent bracing required not something I really thought about
when I was erecting wall frames and sort of stuff but they say 60% temporary
bracing and if you do install temporary bracing and you want to leave it in
place it can then become part of the permanent bracing okay so what the
things we're going to look at in this series of videos is firstly is the wind
classification which we'll look at in this video and then in subsequent videos
we'll look at determining the wind pressure determining or working out the
area of elevation calculating the racking force on the building designing
bracing systems for the subfloor and for the walls checking that we've got even
distribution and spacing about bracing no point having all our braces on one
end of the building and the other ends got nothing in it and we then can can
check the connection of our bracing to the roof and ceilings and floors because
no point the walls bring braced if they're not bolted or connected to our
floor and connected into our roof system so to determine the wind classification
the wind classification or the design gust at wind speed should take into
account the building height the Terrain category the topographic classification
and the shielding classification now there's heaps of regulatory authorities
you know your council and your private certifiers they may provide you with
information they could give you a map to work it out or you can get them off a
lot of websites a lot of shed building companies have those for general
information and I'll put a link in the description shortly from one of those so
you can have a look or as I said you're Council or your private certifier they
may may just give you a wind classification for your area for Sydney
I generally work on an N3 which is getting up there it's one of the higher
ones for Sydney that's just my go-to wind speed unless
on investigation I find out that I need to get it N4
all right so you can work that out or your private certifier or a council can
give it to you there's a link I'll put that in the description so you can have
a look at that document in your own time and that's just there that's the link as
I said I'll put that in into the description that gives you a lot more
detail and shows you how to work out the wind classification for your own area so
once we have the wind classification we then need to work out what pressure that
is going to put on our wall which then we can work out how much bracing we need
so in the next video I'm going to look at wind pressure G'Day, I'm back just let
you know that if you like this video you can subscribe to my youtube channel or
you can follow me on Facebook so you don't miss out on more great videos