Concrete Barge Design need Help for computation for my Undergrad Thesis

[mitchgrunes]

These are probably very dumb questions, and I'm not an engineer, but:

1. Why would you design the home that floats on water in a way similar to the way you would design it on land? Wouldn't it make sense to choose a lighter weight building structure? And maybe one that has a lower cross section to wind and waves?

2. There is no way this is going to be comparable in cost to a land-based home. And the maintenance issues are going to be much greater. There are good reasons that people who own yachts tend to be very wealthy. Is this really practical?

 

[gonzo]

The cost of construction is not only the house itself, but the land. Also, assuming there is land available for sale. There are many floating communities in the world that have been around for a very long time.

 

[mitchgrunes]

The cost of construction is not only the house itself, but the land. Also, assuming there is land available for sale. There are many floating communities in the world that have been around for a very long time.

Yes.

But sometimes there is a cost to using a given floating water location too. I wonder if that applies to the area of interest. And sometimes there are rules against it. Or new rules are created to stop it. I imagine someone trying to build a new floating community in the middle of a river in a national capital, like Washington, D.C. I imagine the U.S. government would step in and force people to leave. Or arrest them for vagrancy. Even if they didn't dump their sewage there.

I also wonder if a typical architect trained in the building of structures on land would necessarily have the knowledge and legal certifications to build a good structure on the water. Though I have no idea how that applies to the o.p. Perhaps that person does.

 

[bajansailor]

@Eric Sponberg has designed some very neat floating homes - here is a photo of one.

Floating Homes https://ericwsponberg.com/boat-designs/floating-homes/

 

[Rumars]

These are probably very dumb questions, and I'm not an engineer, but:

1. Why would you design the home that floats on water in a way similar to the way you would design it on land? Wouldn't it make sense to choose a lighter weight building structure? And maybe one that has a lower cross section to wind and waves?

2. There is no way this is going to be comparable in cost to a land-based home. And the maintenance issues are going to be much greater. There are good reasons that people who own yachts tend to be very wealthy. Is this really practical?

Because:

1. Most people want a certain amount of space and light, including space above their heads. They like their walls straight and with 90° corners whenever possible. What they don't want is living in a basement with only one inch between their head and the ceiling, where all furniture has to be custom made to fit curved walls and odd angle corners, etc. Those who can live with such limitations usually just buy any old yacht/ship and call it a houseboat.
Houseboats are rarely moored in a location experiencing more wind or waves then comparable houses on the shore, there's no need to "beef them up".

2. The cheapest way to build is using the materials the have the biggest market in the area in question. You deviate only if necessary or if the client wishes an upgrade. The home building market is many many times larger then boat or RV building.

Waterway use regulations for houseboats are similar to building permits, you can't just put your houseboat anywhere you like, you must insure wastewater management, etc. Yes, there can be fees associated with this, they're similar to building on leased land or property taxes based on square footage. Depending on how exactly the municipality in question handles this it can be way cheaper to pay for mooring space and mobile wastewater management then buying land in the same general location. These regulations also greatly affect the value of the houseboat, since without the mooring rights the floating structure itself has a completely different value. Sometimes what you pay for is actually taking over the mooring lease, and in some cases just like with historic buildings you are married to the existing boat that you bought.

The building cost structure is the same to structures on land just that foundation and basement work translate into building a pontoon/raft/barge. Exactly like on land the costs and lifespan wary with the clients desire, a few wooden poles under a crawlspace don't compare to a concrete basement just like a plywood box isn't a concrete barge. When compared to building in the same location the houseboats flotation element is usually cheaper overall then the houses foundations because building on a river or canal bank means wet and often instable soil.
Everything above ground/water stays the same cost wise. Even building material choices translate similarly, if you choose heavy materials like brick for your walls you will need more foundation regardless if it's on land or on water.

 

[gonzo]

I imagine someone trying to build a new floating community in the middle of a river in a national capital, like Washington, D.C. I imagine the U.S. government would step in and force people to leave. Or arrest them for vagrancy.

They do that for tent cities and encampments. It is not an issue only on the water. The OP is not asking about available permits for a particular location. That would be a different thread.

 

[Blueknarr]

This is a very good exercise for a land architect to do.

Many years ago the owner of a floating home decided to have it remodeled by land based architect and construction company. Nobody consulted a Navel Architect.

First they marked the existing waterline to determine what was above and below the landline.
Then removed the interior compartments of the concrete float " because they weren't structurally required ".
Cut open the exterior walls for windows from the home improvement store. Staying six inches above the previously determined land level.
Finally a second level was added above. Which brought the water shedding windows to within an inch of the waterline.

The wind blew.
Three inch wavelengths, and induced a slight list.
The windows failed and the house sank.

 

[Adam Salem]

Hello everyone, I am a 5th year Architecture student and would like to ask for help in designing the concrete basin/barge foundation for my floating home design that would have a maximum of 2 floors, and hopefully use the concrete basin as a basement if possible.

Based on my research from the Netherlands, the average weight of a house with fixtures and furniture, plus the family that would occupy the home, would be roughly around 60,000kg to 100,000kg and would be able to accomodate either a bungalow style house or 2 to 3 floor level house.

The dimensions for the shape of the basin would be 8x15 meters. I am in need of help in computing the needed depth for the basin, and the computation for it to float, and the freeboard to be around 1.5m from the waterline, considering this structure would be built and placed along an enclosed lake connected to a river via water gates.

Attached below is a mockup design of the layout and plans. Hopefully, if it is possible, I would like to expand the walls to the very edge of the 8x15m barge instead of building within it, if the calculations offer a possibility of making it happen.

Look, from a practical perspective it's really simple, in fresh water one cubic meter of hole floats 1t. For a house weighing 70-100t you need a hole in the water with a volume of 70-100m3. To make that hole you need something to keep the water out, and that something has its own weight, wich must be added to the weight of the house. The result is you need a bigger hole. Since the footprint of the base plate is fixed at 8×15m the only thing that changes is how deep the hole gets, that's the height of the walls that keep the water out (called draft). 0.834m is for the 100t house, so the question becomes how much the concrete barge weighs, because that weight must fit in the remaining 2.166m.
Example: if we asume a hollow concrete box 15×8×3m with a uniform thickness of 0.25m, we get a total concrete volume of 88.125 cubic meters. At 2.5t/m3 that weighs 220.31t + 100t for the house = 320.31t. The needed hole in the water will be 320.31m3. 15x8x3m has a volume of 360m3, so the barge will sink until 320.31m3 are submerged, that means to a depth of 2.67m, leaving 0.33m as freeboard.

In an academic paper all of this must be explained properly by applying the appropriate equations. You can't just say "I know that 1t of structure needs 1m3 of hole in the water" just like you can't say "the house will weigh 100t" and "the concrete barge will weigh 220t". The professor will want proof for all of that, you must demonstrate that you can indeed calculate the total volume and weight of the structure according to the local law. Otherwise you will be one of those arhitects who are forever in conflict with either the structural engineer, or the client.

P.S. Do you have a 100mm dividing wall under the kitchen island?

Hi , Morileck I have read your posts, I am actually interested in building something similar of your thesis , a river barge that is converted to a house, If you would like to help me in that , I will be very grateful

 

[bajansailor]

@Morileck how is your final year thesis going?
We have not had any feedback from you since September.

 

[messabout]

I know that architecture students are required to pass examinations for Physics, Strength of materials, Stress analysis, and a bunch of other engineering disciplines. Archimedes principle is one of the most elementary studies and it is one of the first of the basics for designing a land based structure. The matter of soil bearing comes into play. At the Thesis level the architecture student will have mastered all of those disciplines and many more.

Is it possible that the OP is using the term architect to describe a different academic pursuit such as construction management or other less rigorous pursuit? Language interpretations perhaps.


Whatever the reality, I wish the OP well.

 

[gonzo]

Archimedes principle is one of the most elementary studies and it is one of the first of the basics for designing a land based structure.

In what part of the design do you use Archimedes principles on a land based structures? I have designed and built many (I am a general contractor and engineer) and never had the need to.

 

[Rumars]

In what part of the design do you use Archimedes principles on a land based structures?

Where there is a high water table and you have to put a basement under the house. More typical for the US are pools in the same situation, they can easily pop out if empty. These are just two very basic basic examples from residential practice, it can get much more complicated.

 

[messabout]

Here in Florida the soil can become soupy during rainy season or after a major storm......as in Hurricane. Gasoline stations have underground tanks that used to surface themselves when near empty. I believe that the problem is solved by putting a certain amount of water in the tank. The gasoline pickup is arranged so that it lies above the water level.

 

[gonzo]

Where there is a high water table and you have to put a basement under the house. More typical for the US are pools in the same situation, they can easily pop out if empty. These are just two very basic basic examples from residential practice, it can get much more complicated.

Empty pools can float. I have been in construction for decades and have never seen a house float away. When the water table is high, leaks are common; floating houses not. In fact, in floods houses may detach from the foundations and float away.

 

[fredrosse]

I was involved with concrete boats as a senior mechanical engineering thesis, way back in 1969. We designed and tested to destruction several concrete panels, with many reinforcement arrangements. Two basic configurations were evaluated, 3/4 inch thick (19mm) hull panels for a 33 ft (10 Meter) boat, and 1-1/2 inch thick ( 38 mm ) panels for a 78 ft (25 Meter) workboat. A few years later we built a 30 ft sailboat, and this concrete boat is still in use on the U S west coast.

Your design challenges are relatively easy to meet all relevant structural and stability design criteria, with hull thickness of about 3 inches, (75mm) more or less. Interior bulkheads, spaced about 6 to 8 ft on centers will provide good structural integrity, multi watertight compartments, and tank storage space for water and fuel, etc. Building similar to a typical spud barge is probably a wise choice. if you want some more technical data, contact me through the website: Beckersville Steam Engineering Co.