How large will the deflection be?

[dadgom]

Anyone who can help me calculate the dimensions I need for the beams for a climbing frame for monkey bars?
I was thinking of having 4 95x95 posts at the corners and then having 4-4.5 meter long beams in between.
Like this:
http://www.lappset.com/se/sv/Produkter/Sok-produkter/Produkt-kort?prodID=175016

If the beams for the top rails are 45x145 and you hang 100kg in the middle. How much will it bend?

 

[Leif i Skåne]

Nothing measurable, but make sure to buy C24 quality, watch out for knots that reach the edges and weaken, and ensure the timber has tight growth rings, but that is usually the case with C24

 

[Bernieberg]

With two 45x145 C24 beams that are freely supported, you get approximately 1.9 mm deflection if you hang 100 kg in the center. If you hang with your entire body weight on one side, that is on one beam, the deflection doubles. Depending on how graceful your climbing is, you'll also get a dynamic addition, perhaps doubling if you're tired and completely lose your finesse .

Calculated with elementary cases for beam bending using material data from Träguiden.

 

[dadgom]

With two 45x145 C24 freely supported, you get approximately 1.9 mm deflection if you hang 100 kg in the center. Depending on how graceful your monkey bars are, you then get a dynamic increase, maybe up to double if you are tired and completely lose your flair .

Calculated with elementary case for beam bending with material data from Träguiden.

Thanks!
Doubling the weight only makes a 4mm deflection then? Plus, I only weigh 70 kg so I have a little margin.
How much difference would there be with pressure-treated wood?

 

[Bernieberg]

Yes, it will be 4 mm if you hang 100 kg on a beam. And then, as mentioned, it will be a bit more when you more or less swing from arm to arm, so to speak.

I can't imagine there's any difference with treated timber (if it's equally dry).