cmose Posted October 20, 2016 Report Share Posted October 20, 2016 Hello forum, I'm quite a wood working neophyte with some experience in areas like rough carpentry. I was hoping that someone might be able to provide some insight into the structural capabilities of Ipe 4x4s. I have a few Ipe 4x4s leftover from building my deck and was thinking about building a swing set with them. I was curious if they were strong enough to build an adult-weight supporting swing set structure. Hopefully this isn't a completely inappropriate question for the forum. Thanks Quote Link to comment Share on other sites More sharing options...
Tpt life Posted October 20, 2016 Report Share Posted October 20, 2016 This depends on the span. If you are going one seat wide, I see no issue. If you try to span more than one seat like kids' sets do, you will want a center support. Can you post a rough sketch? Quote Link to comment Share on other sites More sharing options...
drzaius Posted October 20, 2016 Report Share Posted October 20, 2016 There are resources that will tell you the strength of various types of wood that will help. Ipe is really strong though. I installed it on my deck & even a skinny piece is super strong. Quote Link to comment Share on other sites More sharing options...
cmose Posted October 20, 2016 Author Report Share Posted October 20, 2016 I'll try to get a sketch up this evening, but was targeting a kids-style swing set with space for 2 swings, probably simple A support legs (honestly, I'd probably cheat and use one of the steel A brackets). I haven't been able to find any span information for Ipe dimensional lumber so far, only for deck boards. I tried to make sense of the Elastic Modulus and Modulus of Rupture listed on wood-database.com/ipe but sadly I have insufficient knowledge to translate that into the span capabilities of an Ipe 4x4. Quote Link to comment Share on other sites More sharing options...
..Kev Posted October 20, 2016 Report Share Posted October 20, 2016 Give this a shot.. http://www.woodbin.com/calcs/sagulator/ Quote Link to comment Share on other sites More sharing options...
drzaius Posted October 20, 2016 Report Share Posted October 20, 2016 11 minutes ago, TIODS said: Give this a shot.. http://www.woodbin.com/calcs/sagulator/ 8' span with 400 lbs center load yields a sag of a whopping .03". So I'd say it would easily support a couple of swings. 1 Quote Link to comment Share on other sites More sharing options...
Tpt life Posted October 20, 2016 Report Share Posted October 20, 2016 I get .28" of sag at eight feet. Remember that 4x4 is 3.5x3.5 and the sag is .035 per foot. I don't think that is a deal breaker but a few things could be. Be absolutely sure there are no defects and that you have good straight grain. Quote Link to comment Share on other sites More sharing options...
drzaius Posted October 20, 2016 Report Share Posted October 20, 2016 9 minutes ago, C Shaffer said: I get .28" of sag at eight feet. Remember that 4x4 is 3.5x3.5 and the sag is .035 per foot. I don't think that is a deal breaker but a few things could be. Be absolutely sure there are no defects and that you have good straight grain. Doh! Right you are. I'd make a lousy engineer. Quarter inch of sag still isn't bad though. Quote Link to comment Share on other sites More sharing options...
AJ_Engineer Posted October 20, 2016 Report Share Posted October 20, 2016 Being an exotic, the strengths of ipe are not published in standard engineering manuals But, based on the wood database values you linked, it seems to be about twice as strong and twice as stiff as say a douglas fir. So assuming the ipe is of similar grading (clear no knots) I would expect about twice the capacity out of an ipe 4x4 than a doug-fir 4x4. So if the swings would work with a good 4x4 from the lumberyard, it should work with the ipe. Do realize that does not mean you can replace a 4x8 doug-fir beam with a 4x4 ipe. Quote Link to comment Share on other sites More sharing options...
Chestnut Posted October 20, 2016 Report Share Posted October 20, 2016 A 3.5" x 3.5" Ipe beam using Wood Database's MOR and Young's modulus, information would take a 7,640 lb center load to fail. Bending is a bigger issue but i calculated .22" on an 8 foot span with 600 lbs. This is also worst case because the loading is going to be more distributed which gives the beam more capacity. Quote Link to comment Share on other sites More sharing options...
Tpt life Posted October 20, 2016 Report Share Posted October 20, 2016 7 minutes ago, Chestnut said: A 3.5" x 3.5" Ipe beam using Wood Database's MOR and Young's modulus, information would take a 7,640 lb center load to fail. Bending is a bigger issue but i calculated .22" on an 8 foot span with 600 lbs. This is also worst case because the loading is going to be more distributed which gives the beam more capacity. Don't forget the mounting. Most swing mounting is drilled through. This will affect the calculation quite a bit. I doubt it will affect the swing weight figures, but I doubt you get anywhere near a ton. That's based on causing one to fail on the job after a lag had been drilled through. Quote Link to comment Share on other sites More sharing options...
Chestnut Posted October 20, 2016 Report Share Posted October 20, 2016 It would probably have about a 25% load difference. Remember we beat this horse dead, holes through the center of a beam in either direction have little effect. I=(b*h^3)/12 So it'd flex .3" under use and would yield at 5,000 lbs. Quote Link to comment Share on other sites More sharing options...
drzaius Posted October 20, 2016 Report Share Posted October 20, 2016 So, if it's a 2 elephant swing, your gonna have problems. Quote Link to comment Share on other sites More sharing options...
cmose Posted October 22, 2016 Author Report Share Posted October 22, 2016 Wow, Thanks all. You guys are brilliant! Quote Link to comment Share on other sites More sharing options...
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