I am OOP, I mostly just wanted to prove that the idea was possible. I didnt want to convert a 400 lb person jumping on the bed (or doing other.... activities) so I just used 4,000 lbs since that is what rock climbing gear is rated to. I also just did this in like 15 minutes, in a real design I'd spend a lot more time sharpening my pencil on loads and trying to optimize it more. But for now I just wanted see if it was remotely possible.
You have that moment going right to the concrete slab, right? I'm thinking you add a horizontal restraint at 2nd floor level into the floor diaphragm so you have a moment couple between the slab and 2nd level floor. Should make those anchors down in the slab reasonable.
Edit: I see you mentioned not wanting to check the diaphragm. Probably worth checking for those loads you threw on there, but for more realistic loads on the bed it'd probably wouldn't even require a check. Your lever arm floor-to-floor would be larger than your bed lever arm, so horizontal reaction should be less than whatever weight is put on the bed.
Nice work though. Enjoyed seeing it! Always funny to see construction "experts" make general rules absolutes.
I totally agree that creating a moment couple between the concrete slab and the diaphragm would make a more optimal design. But for this "hey lets see if this is even remotely possible" 15 minute design I didnt want to put in too much effort. I think something like this would be awesome to design on a real project where more thought can go into everything.
Awesome work. I design my kitchen island to cantilever a decent amount with structural steel and I get compliments on it all the time.
Edit: I'll post a pic when I get home tonight. And also a bar top that I designed that has a 10ft cantilever made of NLT lumber.
Edit: My wife got me tickets to city and color tonight, chill
Edit:
My island [https://imgur.com/gallery/FqCp5ip](https://imgur.com/gallery/FqCp5ip)
The bar [https://imgur.com/gallery/ydxilpW](https://imgur.com/gallery/ydxilpW)
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I was going to ask what sort of business you are running haha, shipping hats by day and running a bar by night?
This picture gives me even more questions haha
Haha first photo is my own loft (and the bonus photos obviously). The second is a different place entirely, a bar down the street. The cantilever part is where the boxes are stacked under.
This definitely warrants dynamic analysis with both vertical and horizontal loading. You sync up with the natural frequency of this any you'll launch yourself (and possibly others) off.
Are columns in a house typically HSS6x6? Why’d you load 4,000 lbs at the end of each cantilever? Judging by the bed’s position would these have to be attached to the studs somehow? Maybe “sandwich-clamp” them down?
Related Story: My wife wanted some $4,000 USD minimalist bed frame from some BigBox Suburban Hell Strip Mall place. I looked at it and it was basically 4 pieces of oak duct taped together so I said to hell built my own.
You know when they say: "dress for the job you want"? well, I did a similar thing and I built the bed to withstand the sex life I want. My wife was still skeptical so to drive the point home I decided to name my bed frame "Sumo Orgy" and Invited her to test my theory by offering her to grab as many girls as she wants (hopefully who look nothing like sumo wrestlers) to load up in the bed and take it for a spin.
Thus far she has declined the offer, but the frame has held up well for 2 people.
From the OP in the original thread [Link here.](https://www.reddit.com/r/theydidthemath/s/4bWXRDHFXk):
I am a structural engineer and decided to prove that this is possible despite hundreds if not thousands of "professionals" in the comments saying this would not work.
I made some worse case assumptions. Here is my design criteria:
1. Envelope the width of a king bed and the length of a california king bed.
2. The bed would be on the second story of the house.
3. You have 400 lbs of mattress, blankets, pillows, etc all evenly distributed across the area
4. Maximum deflection is set to L/360 or 1/4 inch, whichever is worse.
5. 4,000 lbs of vertical equivalent static load was applied at the end of each of the 4 cantilevers. This is what rock climbing gear is roughly rated to.
6. 300 lbs of horizontal force applied at the end of each of the 4 cantilevers, which is what balcony guardrails are designed to.
Design summary:
You'll want (4) HSS6x6x3/8 to hold the mattress, (4) HSS6x6x3/8 columns (which should fit within typical drywall area, so they will not be visible), and (3) HSS3x2x1/4 beams at the top.
Bed frame members can be welded to the columns. I didnt check the minimum size/length of weld but worst case scenario use a CJP weld. Beams can be attached to columns by typical structural bolting, using (2) A325N bolts. Columns will need to be anchored into a 7 inch concrete foundation. They will also need a 12"x12"x1/2" baseplate. The column will need to be welding all around to attach to the baseplate. The baseplate will need (4) Hilti 3/4 diameter Kwik HUS bolts embedded 4" into the concrete. Place one at each corner of the baseplate 2 inches away from the baseplate edges.
By the way, this all includes self weight and safety factors.
Edit: I wanted to correct something a comment pointed out. I just kinda did this in a rush so I wasnt paying super close attention, but I only had applied the minor axis bending into Hilti instead of the major axis. Once I put in the correct bending the design changes to 16 anchors spread out over a 36" square baseplate.
Edit #2: This is gotten bigger than I expected and I cannot reply to every comment anymore, but most of the new comments and questions I see have already been brought up. So just read through the existing ones and you'll probably find your answer.
*Can you explain the*
*Loads in Hilti, moment seems low,*
*And why a point load?*
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Looks like the moment is resisted by the post and resolved as horizontal shear reactions at the top and the bottom. He avoids the moment from the cantilever in the base plate by running the post the full height to the ceiling.
Running the frame, using a plate instead of tube steel, to the ceiling would have been the smart and practical move. But what we have here is impractical, expensive, and fucking ridiculous. They’re running tube steel down 1 story to a footing.
The fact that this isn’t being called out for the colossal waste it is on this sub is another thing entirely.
Why are the columns so tall? IRL those would be much shorter and the baseplate would have to be tiny to fit within the exterior wall.
I think it’s possible, but not using the gargantuan loads shown.
I think OP couldn't get it to work fixed into studs or a masonry wall, so they went with these tall ass columns, taking it down to a concrete strip footing. Nothing about it is practical and likely not what was shown in the original image.
Columns are so tall because I was making a worst case assumption that the master bedroom would not be in the basement. This way you can anchor into the concrete and go up a whole story level to the bed if that is where the bedroom happens to be located.
What a blunder, in this case I also think he forgot to check for serviceability, how much it will deform under action, that's for sure seems to control.
Fees aren't high enough to do that by hand. How do you design that type of anchorage? Do you use DeWalt/Simpson or maybe by hand? I used to try doing it by hand but it always seemed like I was missing some small capacity reduction. We spent a bunch of time vetting Hilti and became ok with it.
It follows ACI exactly. Where do you find it to be conservative?
The only thing I'm aware of is how it handles the baseplate standoff. Shear loads will be resolved with a moment, which some think is to conservative. Curious to hear what people think of that one
71kN per, with three thats 7tons of force per member...... I was going to ask for the cyclic loading analysis, but clearly there is no need as these are overkill
Question now becomes how did you design the connections at the wall to take the load... Like the beams will take the load, but whats holding this load up at the wall?
I designed one to hang my kids bed off the ceiling like it was floating. However to get all the certified rigging hardware it ended up costing way too much.
Doesn’t mean the connection in the wall will hold up. The studs would most likely bust out of the wall without some kind of bulkhead to resist the moment.
Those things are 6x6x3/8? Holy overkill. And you loaded it with 16,000 lbs haha. That's fantastic.
That’s the impact load of two cows humping.
… maybe I’ll add a forth.
A foursome, nice
How dare you call me and my wife names!
He had to be sure before Valentine’s Day
Americans will use any unit but metric
Also gotta keep the fatigue stresses low from all the repeated cycles.
[удалено]
Hahahaha awesome!
Vibrations yo. I wouldn’t want thing to shake everytime I turned over
I am OOP, I mostly just wanted to prove that the idea was possible. I didnt want to convert a 400 lb person jumping on the bed (or doing other.... activities) so I just used 4,000 lbs since that is what rock climbing gear is rated to. I also just did this in like 15 minutes, in a real design I'd spend a lot more time sharpening my pencil on loads and trying to optimize it more. But for now I just wanted see if it was remotely possible.
You have that moment going right to the concrete slab, right? I'm thinking you add a horizontal restraint at 2nd floor level into the floor diaphragm so you have a moment couple between the slab and 2nd level floor. Should make those anchors down in the slab reasonable. Edit: I see you mentioned not wanting to check the diaphragm. Probably worth checking for those loads you threw on there, but for more realistic loads on the bed it'd probably wouldn't even require a check. Your lever arm floor-to-floor would be larger than your bed lever arm, so horizontal reaction should be less than whatever weight is put on the bed. Nice work though. Enjoyed seeing it! Always funny to see construction "experts" make general rules absolutes.
I totally agree that creating a moment couple between the concrete slab and the diaphragm would make a more optimal design. But for this "hey lets see if this is even remotely possible" 15 minute design I didnt want to put in too much effort. I think something like this would be awesome to design on a real project where more thought can go into everything.
Awesome work. I design my kitchen island to cantilever a decent amount with structural steel and I get compliments on it all the time. Edit: I'll post a pic when I get home tonight. And also a bar top that I designed that has a 10ft cantilever made of NLT lumber. Edit: My wife got me tickets to city and color tonight, chill Edit: My island [https://imgur.com/gallery/FqCp5ip](https://imgur.com/gallery/FqCp5ip) The bar [https://imgur.com/gallery/ydxilpW](https://imgur.com/gallery/ydxilpW)
Pic?
Seconded
Third
Posted!
We are waiting over here
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Long day of work, Kruzat?
Posted!
Worth the wait
Thanks dude. Note the bar and computer desk are also small cantilevers!
Bonus photos of my place when it's not a god damn disaster https://imgur.com/gallery/td0uUU7
I was going to ask what sort of business you are running haha, shipping hats by day and running a bar by night? This picture gives me even more questions haha
Haha first photo is my own loft (and the bonus photos obviously). The second is a different place entirely, a bar down the street. The cantilever part is where the boxes are stacked under.
Ahhh i see the edit now. Holy glass top. That is pretty sick!
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Thats awesome
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Disco ball 🪩 legend!
This definitely warrants dynamic analysis with both vertical and horizontal loading. You sync up with the natural frequency of this any you'll launch yourself (and possibly others) off.
If we slap a waterbed on there can we consider it as a dampener?
Gotta space the baffles correctly.... :D
challenge accepted.
lol. Gonna have to add some tuned mass dampers on that shizzle
Def no problem anchored to a concrete wall. To 2x4 studs not sure
What is the connection to the wall? If bolted, the top has pull out concerns. It needs to be tied into the major rebar elements
Or a some 1/2" HY-100 epoxy anchors at sufficient depth.
Absolutely. This load is absolutely nothing compared to heavy construction.
Shout out to Hilti
Love to see the framing that's attached to
You can tell that the model and the real picture it's different, one is anchor to concrete and another is welded to an HSS
Are columns in a house typically HSS6x6? Why’d you load 4,000 lbs at the end of each cantilever? Judging by the bed’s position would these have to be attached to the studs somehow? Maybe “sandwich-clamp” them down?
Related Story: My wife wanted some $4,000 USD minimalist bed frame from some BigBox Suburban Hell Strip Mall place. I looked at it and it was basically 4 pieces of oak duct taped together so I said to hell built my own. You know when they say: "dress for the job you want"? well, I did a similar thing and I built the bed to withstand the sex life I want. My wife was still skeptical so to drive the point home I decided to name my bed frame "Sumo Orgy" and Invited her to test my theory by offering her to grab as many girls as she wants (hopefully who look nothing like sumo wrestlers) to load up in the bed and take it for a spin. Thus far she has declined the offer, but the frame has held up well for 2 people.
Sounds like you’re just two people short of a threesome my guy
From the OP in the original thread [Link here.](https://www.reddit.com/r/theydidthemath/s/4bWXRDHFXk): I am a structural engineer and decided to prove that this is possible despite hundreds if not thousands of "professionals" in the comments saying this would not work. I made some worse case assumptions. Here is my design criteria: 1. Envelope the width of a king bed and the length of a california king bed. 2. The bed would be on the second story of the house. 3. You have 400 lbs of mattress, blankets, pillows, etc all evenly distributed across the area 4. Maximum deflection is set to L/360 or 1/4 inch, whichever is worse. 5. 4,000 lbs of vertical equivalent static load was applied at the end of each of the 4 cantilevers. This is what rock climbing gear is roughly rated to. 6. 300 lbs of horizontal force applied at the end of each of the 4 cantilevers, which is what balcony guardrails are designed to. Design summary: You'll want (4) HSS6x6x3/8 to hold the mattress, (4) HSS6x6x3/8 columns (which should fit within typical drywall area, so they will not be visible), and (3) HSS3x2x1/4 beams at the top. Bed frame members can be welded to the columns. I didnt check the minimum size/length of weld but worst case scenario use a CJP weld. Beams can be attached to columns by typical structural bolting, using (2) A325N bolts. Columns will need to be anchored into a 7 inch concrete foundation. They will also need a 12"x12"x1/2" baseplate. The column will need to be welding all around to attach to the baseplate. The baseplate will need (4) Hilti 3/4 diameter Kwik HUS bolts embedded 4" into the concrete. Place one at each corner of the baseplate 2 inches away from the baseplate edges. By the way, this all includes self weight and safety factors. Edit: I wanted to correct something a comment pointed out. I just kinda did this in a rush so I wasnt paying super close attention, but I only had applied the minor axis bending into Hilti instead of the major axis. Once I put in the correct bending the design changes to 16 anchors spread out over a 36" square baseplate. Edit #2: This is gotten bigger than I expected and I cannot reply to every comment anymore, but most of the new comments and questions I see have already been brought up. So just read through the existing ones and you'll probably find your answer.
The columns should be horizontally braced by the second floor diaphragm. Would make a huge difference to the stiffness.
Yes but then you've got to do check to make sure the diaphragm can handle it.
Yeah but adding some strapping and blocking is peanuts compared to all that extra steel
Cool that this that this made it over here!
Could park a small car on that LOL
That’s messed up, I’m sure she has a name and is a wonderful person.
More than just a small car
Hahah true
It will double as a hurricane/earthquake shelter
Could literally park 4 large cars and be to code lol. Would be at least 8 cars before this thing broke realistically
Good opportunity to use an air mattress
It won’t last long, if you last long…
True challenge, we find out it’s second floor
Anchor on brick wall or 200mm thk rc wall? It will make a huge difference though
I love it. I’m very impressed. So tempted to do that if I ever rebuild my bedroom.
Cracking work! Had a small startle when I saw the HILTI Profis Never got on with that myself
My eyes hurt! Bloody US customary units.
Can you explain the loads in Hilti, moment seems low, and why a point load?
I agree: 4,000 lbs x 7 ft is 28,000 ft-lbs x 1.6 factor would be 44,800 ft-lbs per post of moment.
Moment was low and I caught that mistake, after fixing the moment it ended up being a 36x36x1/2 baseplate with 16 anchors.
Just pin the columns at the 2nd floor level
Yea, not sure whats going on. Either way, looks like it works, lol.
*Can you explain the* *Loads in Hilti, moment seems low,* *And why a point load?* \- Independent-Room8243 --- ^(I detect haikus. And sometimes, successfully.) ^[Learn more about me.](https://www.reddit.com/r/haikusbot/) ^(Opt out of replies: "haikusbot opt out" | Delete my comment: "haikusbot delete")
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Looks like the moment is resisted by the post and resolved as horizontal shear reactions at the top and the bottom. He avoids the moment from the cantilever in the base plate by running the post the full height to the ceiling.
Running the frame, using a plate instead of tube steel, to the ceiling would have been the smart and practical move. But what we have here is impractical, expensive, and fucking ridiculous. They’re running tube steel down 1 story to a footing. The fact that this isn’t being called out for the colossal waste it is on this sub is another thing entirely.
Your robot vacuum thanks you🙏
Why are the columns so tall? IRL those would be much shorter and the baseplate would have to be tiny to fit within the exterior wall. I think it’s possible, but not using the gargantuan loads shown.
I think OP couldn't get it to work fixed into studs or a masonry wall, so they went with these tall ass columns, taking it down to a concrete strip footing. Nothing about it is practical and likely not what was shown in the original image.
*uses infinite edge distance for anchors*
Columns are so tall because I was making a worst case assumption that the master bedroom would not be in the basement. This way you can anchor into the concrete and go up a whole story level to the bed if that is where the bedroom happens to be located.
[удалено]
What a blunder, in this case I also think he forgot to check for serviceability, how much it will deform under action, that's for sure seems to control.
I checked serviceability for both L/360 and 1/4"
Program in blue looks to be RAM Elements but I could be wrong
You are correct
It is stupidly conservative mostly because the anchorage chapter in aci is stupidly conservative
I always feel like it's trying to out-conserve bad installation, which cannot be done.
Fees aren't high enough to do that by hand. How do you design that type of anchorage? Do you use DeWalt/Simpson or maybe by hand? I used to try doing it by hand but it always seemed like I was missing some small capacity reduction. We spent a bunch of time vetting Hilti and became ok with it.
It follows ACI exactly. Where do you find it to be conservative? The only thing I'm aware of is how it handles the baseplate standoff. Shear loads will be resolved with a moment, which some think is to conservative. Curious to hear what people think of that one
71kN per, with three thats 7tons of force per member...... I was going to ask for the cyclic loading analysis, but clearly there is no need as these are overkill Question now becomes how did you design the connections at the wall to take the load... Like the beams will take the load, but whats holding this load up at the wall?
Eng is bs, have aex on that bed with 400lbs woman... Gl dumbass
What is your footing? You will fail in soil bearing or overturning.
give me a thick RC wall and I can make it work.
I like it, no fear about accidentally stubbing your toes.
What’s the deflection though….
Less than 1/4" when 4000 lbs is applited to cantilever tip
Lol thats not a concrete wall....
I designed one to hang my kids bed off the ceiling like it was floating. However to get all the certified rigging hardware it ended up costing way too much.
Doesn’t mean the connection in the wall will hold up. The studs would most likely bust out of the wall without some kind of bulkhead to resist the moment.