Outdoor Kitchen 2

[matttay]

Hello. I'm EE, but trying to learn a bit about structures before meeting with structural engineer for plans. Before I meet with him I'd like to understand options since I have a lot of lattitude to change dims if I can understand the tradeoffs.

I'd like to build a freestanding outdoor kitchen roughly 20' x 18' x 10'. A PE will obviously design it, but it looks like 6/12 scissor truss can span 20', and a glulam beam 12" deep can also span 18' at load. Beams can rest on roughly 6x6 or 8x8 treated posts, which will need to be buried 2-3 feet deep for lateral stability in roughly 1' dia concrete post. All structural stuff will be wrapped with framing + felt + stone veneer or some sort of siding.

Is this usually how these things are built? I'm not crazy about large knee braces, and exposed heavy timbers aren't part of existing architecture.

Also, would steel posts be preferred? As I look around I see a lot of free standing structures with concrete post rising ~3' above ground and steel bolted to that.

I'm in Seattle, with 1 ft frost and earthquake worries.

Thanks very much.

 

[SperlingPE]

Let me first understand this structure. You are envisioning a 4 post structure w/ beams and wood trusses. There will be no walls and all support elements will be covered.
From your post it sounds like you are headed in the right direction for resisting vertical downward loads on your structure. The engineer will look at what it will take to resist lateral loads (seismic and wind) as well. If you don't want any braces, the engineer will look at using a moment connection between the beam and the column. This type of connection will resist rotation at the joint between the beam and column. The lateral loads should be fairly small (I am guessing), so it should be possible to up with the connection design using wood or steel. Since you want to cover the structure, steel will probably be easier to connect but might cost more than wood. Again, I am not familiar with your area of the US to make a good assessment. Using moment connections may also affect your foundations, depending on the connection between the column and the foundation.

 

[UcfSE]

If you don't want large timbers or knee braces I suggest you consider steel. It's easier to make connections to resist lateral forces with steel than it is with wood and braces probably won't be required for something that small. It probably costs more for steel though, as SperlingPE pointed out. Reinforced concrete or masonry might be an option also, but again you would be looking at costs in your area for that type of construction. I don't know how common that is in Seattle.

Another thing you might be able to do is to design your posts to act as cantilevers sticking up from the ground to take all the lateral load. If they are embedded deep enough they could possibly work. You may or may not have bigger posts but they would still be wood and then everything else is a matter of connections and vertical forces. That might keep the steel out of it.

 

[matttay]

Thanks very much guys.