# Cantilever Design

1. Jun 14, 2009

### Shane

Hello all, I am a physics major working on my mechanical eng. minor. This is not homework. This is a real design.

I have been asked by an engineering friend to help on a cantilever design which he is going to build on his riverside home. I have some structural design under my belt but have never implemented a cantilever design. THIS IS NOT COMMISSIONED. I am not being paid for this. Here is my problem:

The design is to consist of four 13 foot long horizontal beams, each supported by a 9 foot long vertical beam. All will constructed out of simple steel fabrication methods. How am I to anchor these beams? I was wondering if there is some industry standard for the amount and placement of the concrete anchors available as a general guideline. The design is simple, and attached is a terribly crude ASCII sketch of the side.

So now, how do I anchor these badboys? How much cement to use? Where do I place cement? Someone was telling me about some 40% rule but could not remember the details. Dead load of roof will be about 1 lbs per sq foot and live load will be somewhere around 10 lbs per sq foot. Also to consider are possible 85 mph winds that plague the riverside which is where it will be constructed. Any ideas anyone? Or does anyone have any good cantilever resources? I have a structural engineering book but honestly its not too helpful.

Thanks
Shane X.

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• ###### cantileverASCII.jpg
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2. Jun 16, 2009

### KLoux

Local building codes might provide some guidance...

3. Jun 16, 2009

### Shane

The local guys gave basic concrete instruction but said to consort an engineer. The engineers want to charge $300-$500 minimum for any help. I have asked several other people in construction but none of them have dealt much with cantilevers. Construction is pretty basic around here. If someone could lead me to the mathematics I could figure it out, having done quite a bit of structural analysis already, but I just can't seem to find much literature on the subject. Thanks for the help but any other ideas?

4. Jun 29, 2009

### stewartcs

Did you check the local building codes yet?

Other than that any Mechanics book will cover the concept of a cantilevered beam as well as various anchoring and fastening considerations.

I'm really surprised your structural engineering book doesn't have anything in it. Try to Google some books on "concrete cantilevered platforms" and see what you get (if you need a reference specific to this problem).

Since this is for a project, the instructor probably just wants to see your engineering approach to the problem and not necessarily a design that one could actually use.

Hope this helps.

CS