Hi to all
I wonder if anyone here can help me. Shortly I plan to build a new growing on tank in my garage. I intend the measurements to be around 12’ long, 7’ wide and 4’ deep. I intend making this from wood and fitting a box welded liner in it. Basically a timber frame with ply inside. I intend using 100mmx50mm wood frame. The distance between the framework on the long side is 1 foot longitudinally. In other words beams running the length of the tank at 1 foot spacing. I have done this before on smaller tanks and it has worked well.
My question is do people think that this tank will be strong enough? I can try and draw a picture but I’m not to good at that.
Regards Alex
Timber pond construction ??
Moderators: B.Scott, vippymini, Gazza, Manky Sanke
Hi
I think I am of the same opinion as both of you. Thats why I thought I'd post just to see if anyone else had been here. The other routes open are:-
1 A smaller pool. I dont like this idea as I like Koi to have max room.
2 Use blocks, trouble is expense, labour and thickness of wall, also was planning full insulation so wanted to place pool on beams, rather than concrete
3 Use a metal frame instead of wood.
Unless there are other suggestions
Regards Alex
I think I am of the same opinion as both of you. Thats why I thought I'd post just to see if anyone else had been here. The other routes open are:-
1 A smaller pool. I dont like this idea as I like Koi to have max room.
2 Use blocks, trouble is expense, labour and thickness of wall, also was planning full insulation so wanted to place pool on beams, rather than concrete
3 Use a metal frame instead of wood.
Unless there are other suggestions
Regards Alex
Hi Alex
The greatest pressure on the sides will be at the bottom, so if it will bow anywhere, it will be right down low!
As you intend to insulate underneath by raising the base on battens, you could always place the botton beams across the width and tie them to the lowest side timbers - that vwould stop the bow at the bottom.
When you say 4ft deep, I assume that's the width of the ply boards - not the actual water depth? If Im right, you'll have the height of the bottom beams (75/100mm?) and thickness of the base ply (18/20mm?) plus the height from the final water level to the top of the tank (probably between 75 and 150mm) to deduct from the 4ft depth of the tank. Therefore the maximum actual depth of water is only likely to be 3ft 6", probably less!
Remember, it's the depth of water that adds to the pressure on any point in the pond/tank. The pressuer will always be equal in all directions and will be greatest at the bottom. The total force pushing on the sides will increase with area and will be spread over the whole area, but again, the greatest force will be pushing on the bottom of the sides and it will reduce proportionally with the depth of water as you move up the sides.
I'm no expert and wouldn't take any chances, but I reckon if you tied the sides using the borttom beams and increased the timbers to 150 x 50 (at least the bottom two) you shouldn't have any problems.
Good Luck.
Bob
The greatest pressure on the sides will be at the bottom, so if it will bow anywhere, it will be right down low!
As you intend to insulate underneath by raising the base on battens, you could always place the botton beams across the width and tie them to the lowest side timbers - that vwould stop the bow at the bottom.
When you say 4ft deep, I assume that's the width of the ply boards - not the actual water depth? If Im right, you'll have the height of the bottom beams (75/100mm?) and thickness of the base ply (18/20mm?) plus the height from the final water level to the top of the tank (probably between 75 and 150mm) to deduct from the 4ft depth of the tank. Therefore the maximum actual depth of water is only likely to be 3ft 6", probably less!
Remember, it's the depth of water that adds to the pressure on any point in the pond/tank. The pressuer will always be equal in all directions and will be greatest at the bottom. The total force pushing on the sides will increase with area and will be spread over the whole area, but again, the greatest force will be pushing on the bottom of the sides and it will reduce proportionally with the depth of water as you move up the sides.
I'm no expert and wouldn't take any chances, but I reckon if you tied the sides using the borttom beams and increased the timbers to 150 x 50 (at least the bottom two) you shouldn't have any problems.
Good Luck.
Bob
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GERRY5
- Great White Shark
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thats 2095 galls .....the depth and width sound ok but the overall length of 12foot would take a fair bit of bracing to prevent any bowing imho..
wooden based ponds have been built and are in use ,certainly at cuttlebrook koi farm , mark and lisa have spawning tanks which are as deep as four foot about five to six foot wide but are about eight foot long and fibreglassed so a fair sized pond is possible , but twelve foot may be a bit to long ...good luck and keep us posted on what you decide to build and with what materials...
have to agree also with bob that the most pressure will certainly be on the base of the pond , so thats where the main strength must be ...we are looking at nearly 10 tons of water in this pond
wooden based ponds have been built and are in use ,certainly at cuttlebrook koi farm , mark and lisa have spawning tanks which are as deep as four foot about five to six foot wide but are about eight foot long and fibreglassed so a fair sized pond is possible , but twelve foot may be a bit to long ...good luck and keep us posted on what you decide to build and with what materials...
have to agree also with bob that the most pressure will certainly be on the base of the pond , so thats where the main strength must be ...we are looking at nearly 10 tons of water in this pond
Hi
Thats where I partially got the idea, from seeing the tanks at Cuttlebrook. I know they derive quite alot of strength from the fibreglass as well. I will try to get one of the guys at work to draw it and carry out a stress analysis, see where the weak points are on Wednesday. I'll post the results.
Like you say 10 ton of water coming out quickly wouldn't be much fun.
Regards Alex
Thats where I partially got the idea, from seeing the tanks at Cuttlebrook. I know they derive quite alot of strength from the fibreglass as well. I will try to get one of the guys at work to draw it and carry out a stress analysis, see where the weak points are on Wednesday. I'll post the results.
Like you say 10 ton of water coming out quickly wouldn't be much fun.
Regards Alex
In theory it can be done, but as pointed out by ohers I think you will need a few cross braces to give the structure some strength and rigidity. I think your best bet is to go for a steel frame top and bottom. That way you can avoid the cross braces which won't do the fish any good if they decide to jump/flick/flash!
Using the calculator in the link from the following thread you get a total force of just under 6000lbs (I like old money! 
)
http://www.koiquest.co.uk/forum/viewtopic.php?t=5054
This averages out at just under 1lb per sq inch pressure. But it would be 2psi at the bottom and vitually nothing at the top.
An 8 stone woman on stilletto heels (if we assume each heel has a quarter of an inch surface area) excerts a force of 224 psi (8 x 14 x 2)
.
I think we often get frightened by the total weight of the water in our ponds rather than the pressure being excerted on them - and then over engineer them.
I have a formula for working out the pressure of water at any depth somewhere - I just can't find it at the moment!
Cheers
Bob
)http://www.koiquest.co.uk/forum/viewtopic.php?t=5054
This averages out at just under 1lb per sq inch pressure. But it would be 2psi at the bottom and vitually nothing at the top.
An 8 stone woman on stilletto heels (if we assume each heel has a quarter of an inch surface area) excerts a force of 224 psi (8 x 14 x 2)
. I think we often get frightened by the total weight of the water in our ponds rather than the pressure being excerted on them - and then over engineer them.
I have a formula for working out the pressure of water at any depth somewhere - I just can't find it at the moment!
Cheers
Bob
-
macaws fly
- Nurse Shark
- Posts: 122
- Joined: Tue Dec 27, 2005 8:49 pm
- Location: north herts
if we are taking the 12foot lenght as being the weak point then this is what i think.
with making it out of wood then no matter how it was made then without a brace across the top of the 12 foot lenght it will bow outwards. wood is funny stuff, yes its strong but if you apply constant pressure to it then over time it will deform. the room you are building it in will be very damp and humid so the wood wil soak up all this moisture and be more flexible.
yes there maybe only a couple of pounds pressure for every square inch but that pressure is EVERY square inch and without and bracing the 12foot lenght will have to support a lot of weight.
the bottom is supported by the base structure along its length so that should be fairly safe.
so i would say if you build it it may look alright for a few weeks/months but it will deform
most pond builders would frown on you if you were to build it from a single thickness of 4inch blocks with render and fibreglass. so nailing a few bits of wood trogether with some sheets of plywood and a box-welded liner would be a big no-no.
with making it out of wood then no matter how it was made then without a brace across the top of the 12 foot lenght it will bow outwards. wood is funny stuff, yes its strong but if you apply constant pressure to it then over time it will deform. the room you are building it in will be very damp and humid so the wood wil soak up all this moisture and be more flexible.
yes there maybe only a couple of pounds pressure for every square inch but that pressure is EVERY square inch and without and bracing the 12foot lenght will have to support a lot of weight.
the bottom is supported by the base structure along its length so that should be fairly safe.
so i would say if you build it it may look alright for a few weeks/months but it will deform
most pond builders would frown on you if you were to build it from a single thickness of 4inch blocks with render and fibreglass. so nailing a few bits of wood trogether with some sheets of plywood and a box-welded liner would be a big no-no.
the fibreglass makes a lot of difference! So does 6x3! A 2x4 would look like a mere twig by comparison. I wouldn't trust 2x4 to hold up my decking, which in places I had to used so I placed blocks underneath to stop it bowing. I weight about 80kg and am only on the decking momentarily! 10,000 kg in a wooden linered pond with no bracing, I wouldn't want to be standing next to it.
Mr Hart might have a few things to say considering what happened to his plastic QT tank.
Mr Hart might have a few things to say considering what happened to his plastic QT tank.
hi alex if this works it's a link to one i built this winter it's only filled to 725gals but works ok.
http://www.koivista.com/display_series.php? ... neuron=280
http://www.koivista.com/display_series.php? ... neuron=280
