Selection of deck footings with respect to lateral load

[Sharky58]

In my little miniseries about my deck construction, I am now facing something where I don't dare to guess myself and can't find anything comprehensively described anywhere.

Description of the deck:

Deck on a slope, approximately 90 sqm, 13 m wide and 6-8 meters deep depending on where you measure on the house body.
Towards the ground by the house body and 3m high at the front edge. The deck will be enclosed all around with 2m high horizontal paneling to harmonize with the house. (reduced height towards the house body, of course).
Gap between the panel and the ground.

Planned design of foundations/posts:

Benders 500mm ground foundations with adjustable post bases. Foundations recessed and cast in the ground. Foundations in a 1600x1800 mm matrix. 90x90 laminated posts.
Cross-braced between all posts taller than approximately 1.5 meters. The fence is held by hangers attached at the top to the floor joists and at the bottom supported by horizontal 45x95 attached to the bottom edge of the outer row of posts.
The outer rows of posts are located about 200mm inside the hangers.

As far as I can understand, the foundations should be okay with the vertical load if placed on ground plates in the dug holes. But what about the adjustable foundations and the side/horizontal load due to the fence? Is it sufficient to cross-brace between the load-bearing posts and to horizontally relieve near the attachment as I have planned?

Göran

 

[justusandersson]

The best is to have diagonals in the deck's plane. If you have that, you can skip vertical diagonals between the posts. Lay out a drawing in plan view and it's easier to show how it should be done.

 

[Sharky58]

Like this?


That's the drawing I have with me right now

/Göran

 

[justusandersson]

Mount diagonals on the underside of the support beams as indicated by the red lines on the attached copy.

 

[Sharky58]

Is it really that simple to do it right And I thought I was going to mark all the posts until I puked.

Note that the terrace is floating from the house and is only attached to the lower parts of the balcony posts (solid cast plinths for them). The pergola ("wart" at the top right lies flush against the ground, so there will probably be no need for a brace there).

Dimensions for the diagonals? Is 45x170 enough for the board against the underside of the beams?

/Göran

 

[justusandersson]

It's probably enough that everything is attached to the balcony posts. No heavy dimensions are required for the diagonals. 45x170 is a bit overkill.

 

[corre]

Isn't it working with nail plates, the wider model? Tension it a bit and screw into each stud.

 

[justusandersson]

If you are going to use spikband or wires, you must make a cross, a diagonal is not enough. Otherwise, it works just as well.

 

[corre]

According to the drawing, will that be the effect? Or does it need crosses in each compartment?

 

[justusandersson]

I think in that case, 2 crosses are needed. But it's not science.