Will triple bunk beds cause a bedroom floor to collapse? 7

[DurableEfficientGood]

The main thing I want to know is whether heavy-duty tri-level bunk beds will overload the floor. There is currently a severe housing shortage in a not-insignificant part of the country and worldwide.

Let's say in a hypothetical (and slightly somewhat realistic) scenario that the housing shortage gets so severe that people have to sleep in any indoor dry room (including living rooms, dining rooms that are not part of the kitchen, and foyers) they can find. Since all the dry rooms have already been occupied by multiple other sleepers each, they now have to resort to having only bunk beds in all bedrooms. Of course, having that many of people in any property unit is currently illegal due to timely evacuation under current fire laws, but let's say that it's been waived for this scenario. Let's also say that none of the buildings have been reinforced for this, but meet all other codes and are maintained in great condition.

The minimum load (unknown if that means rated or design limit) for "sleeping rooms" (according to the IBC) is 30 psf. Let's say that the weight of the heavy-duty steel king-size triple bunk bed is 400 lbs (very high estimate), all 3 king-size mattresses are each 180 lbs (highest amount for commercially produced ones), and that all 3 mattress topping sets are comprehensive and are each 30 pounds (extremely high estimate). This means that the bed setup has an overall empty operating weight of 1030 pounds, which is the same as the curb weight of a 4-seater golf cart. A king size bed has dimensions of 76 inches by 80 inches.

Let's also give an aisle on one side of the bed so that people can get on without passing through other beds. Let's make the aisle have the width as that in a school bus, which is 12 inches. However, the aisle is shared between facing beds, so that the aisle width per unit cell is only half that. Assume that each bed corner support post is 2 inches by 2 inches (fairly small estimate). That gives a bedset unit cell of 86 inches by 84 inches, which is an area of 7,224 in^2 = 50.16667 sqft.

Let's say that everyone who sleeps in the bed is the heaviest person who is healthy. The tallest height for a healthy person is 6'6", the heaviest sex for any given height is male, and the heaviest weight for 6'6" is 230 pounds. That means everyone sleeping in the bed is an extremely muscular (but not insanely, because being too muscular is unhealthy) 6'6" tall male. 2 of these men are able to fit with plenty of space remaining in a queen size bed, while 3 of them cannot fit in it without one turning his body or sleeping on top. So, 3 of these men sleeping on every king-size mattress was chosen because they give the greatest density within a standard size while being able to totally fit inside. The weight of clothing and shoes are insignificant, so they will be ignored here. The total weight of all men on the bed is 2070 lbs. This gives a total system bed weight of 3100 pounds, which is the heavy-duty bed can definitely support. This means each unit cell has a night average load concentration of 61.794 psf. Let's also say that they do not have to work and genuinely enjoy sleeping with each other during free time (and they all rapidly become best friends forever within a week from that), so they spend an average of 20 hours laying in bed, 12 cumulative of them being sleep, for every calendar day including weekends and holidays.

If all dry rooms (including bedrooms) were loaded to a 20-hour average of 61.794 psf and all wet rooms loaded to a 24-hour average of 40 psf, both in every calendar day, in a well-maintained, light wooden-framed multi-storey building that was built to the minimum standard (30 psf for bedrooms and 40 psf for other dry rooms) in a location that is seismically stable, has little wind, and has little snow, will it have a not-insignificant chance (e.g., greater than one in a million chance of collapsing within any given year) by itself of causing the bedroom floors to pancake on top of each other? Will it even have a not-insignificant chance of causing the entire building to collapse? Given that it's well maintained and located in a geographically easy place, external factors such as natural disasters, water damage, erosion, and termite damage will not be a thing here. The only factor remaining will be structural. Also, this is way different from college students crowding together and dancing in a room because there are severe impact loads and significant resonance there but no impact loads here.

 

[hokie66]

Science fiction is not really the reason for this forum. We prefer to deal with the realities of the world we live in.

 

[DurableEfficientGood]

Actually, this isn't science fiction, and is instead realistic fiction, because it doesn't even come close to violating any laws of hard science and the mechanisms are all known here, unlike faster than light travel (violates causality) or electrogravitics (doesn't violate anything but mechanism not close to being known yet).

 

[DurableEfficientGood]

I just want to know whether the floor will have a significsnt chance of collapsing or at least have a significant chance of being structurally damaged under these very specific conditions or not.

 

[Tomfh]

Your question has been answered several times in this thread.

 

[DurableEfficientGood]

I see.

 

[DurableEfficientGood]

To make it simple, will 3 230-lb men on each mattress in this bed:

https://adultbunkbeds.com/triple-bunk-beds/king-triple-bunk-bed

in a bedroom that barely fits these 2 beds (but with ladders placed in the aisle rather than end) and leaves a 1-foot wide aisle in the middle (it has a sliding door or door opens outwards so no room is needed to open the door) cause that bedroom floor to collapse? There will be 18 of those men total here, as there will be 18 total compact bedspaces (or 12 extended width bedspaces).

 

[JDV22]

They would be used in the US and Canada, just that it is a hypothetical in which the population is much larger, cellular agriculture gets perfected so everyone has plenty of food despite limited farmland, there is net zero GHG emissions, there is no crime and everyone is friendly, people are immortal, and everyone is a huge healthy, strong, and handsome white male, but everything else stays the same.

I went down the rabbit hole and the only way I can wrap my head around all of OP's threads is that it seems like OP is trying to write a book of some sort, and really is just looking to see if some of their details can be vaguely realistic??

If this is meant to be taken realistically: - No. a floor designed for 30 psf loading should not be used for what you are proposing if the anticipated loading is 60psf. We cannot give you a hard and fast safety factor because there are dozens of failure modes with hundreds of variables starting from the tree that was cut down to the framer who swings the hammer. Safety factors are meant to account for the unideal circumstances that separate the engineering world from the science world. In my mind, safety factor does not equal reserve capacity.

If this is to be taken as a tip for your book or whatever hypothetical scenario is being played out: It is feasible to think that a single house somewhere could be overloaded and last for several years without any damage based on the variability I described above - it would certainly be a gamble though.. It is not feasible to think that a whole block of houses would be as lucky.

 

[rb1957]

the social implications of 18 people sleeping in one small room far outweigh the structural implications.

I can't imagine a scenario where this isn't fiction, together with a "no crime" and "everybody is friendly".

I'm curious why everyone is a "handsome white male" ... ??

another day in paradise, or is paradise one day closer ?

 

[LittleInch]

And ".... are such close friends anyway, they'll almost certainly sleep naked together at least occasionally, and the 9 men within each shared bed will soon become gay and decide to call themselves a family."

I think the true nature of this long post reveals itself here....


Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[dold]

...there is no crime and everyone is friendly, people are immortal, and everyone is a huge healthy, strong, and handsome white male, but everything else stays the same.

Problem solved bud! No biggie if the building falls down.

Also, since they are so close together anyway, the shower stall will be widened and each mattress-mate will shower 3 together, dividing the time in 3. When they're sleeping so close together and are such close friends anyway, they'll almost certainly sleep naked together at least ocassionally, and the 9 men within each shared bed will soon become gay and decide to call themselves a family.

I'm starting to think that some computer science researcher is testing an AI chatbot on us here. This is beyond absurd. But thanks for the laugh OP.

 

[FoxSE14]

...dold may be on to something re: AI chatbot. Allow me to help his/her algorithm and our profession with some inputs:

1. Kwan Kok Ko, you will likely find that employing the services of a structural engineer will be helpful to answer your questions.

2. Just so you are aware,Kwan Kok Ko, most SEs prefer a rate of $750/hour (USD) in July 2022. A fair rate could also be more. A fair rate might also be less. Most SEs would prefer $750/hour.