Lots of questions on pond design.
  • NeliNeli December 2011
    Posts: 1,205

    Hi Harry,
    Good to hear from U!
    Q
    Ho ho Ho…Merry Christmas to you and everybody here
    A
    He h ehe! Is that a father Xmass laugh? (ho ho ho!)
    Merry Xmass to U and the family, and lots of joy!

    Q
    Before you proceed further….I must highlight to you one more time that the concrete blocks can never be a proper water retaining wall structure. Many people have built using concrete blocks or brickworks to great success based on tried and the traditional forms of construction. My observation is that they all have good ground conditions, the earth is well consolidated and the ground drains off well. A well consolidated ground will not undergo minimum secondary settlement if the new imposed load is less that it overburden load. A well drained ground condition is generally porous in nature where the active pore water pressure cannot be built up at the side of the wall and the water table is deep below the earth.
    A
    U said never...
    U said well drained ground condition...I think my subsoil is good.Do I add some sand on the bottom for better drainage?

    Let us consider the various possible scenarios of your loading conditions.

    Q
    Let assume your pond water depth will be 1.8m. You need to have a wall base of 800mm to a height of 1m and the remaining height cab be 400mm to a height of 1m.
    A
    What do U mean wall base.
    Q

    You will set your concrete block in position when the concrete is soft. This gives you a good key and bond. Construct reinforced columns stiffeners (4nos Y10 c/c 6mm diameter as link at every R6@200 c/c) at the corner and at every 3m c/c along the wall to provide restraint to your concrete block works. It should have a bonding tie 6mm diameter x 800mm length bar over the centre of the stiffener at every 200mm lift in the height of the wall.
    A
    column stiffeners?????Is that some thing that joins The column stiffeners to the blocks in the wall...Is it just a bar (bonding tie)...800mm long, tied to the column stiffener.
    Now concrete blocks if I am not mistaken are higher than 20cm...at list a bit...do I put that bonding tie between the horizontal block lines as I build each line of blocks?

    Q
    When you lift the concrete blocks as you built…..use the stretcher bond to arrange your block by overlapping between courses……so that the block works can distribute load and provide stability. Stretcher bond will allow bonding along the length of the wall they are laid with the vertical joints between bricks lying directly under and over the centre of bricks in the courses under and over.
    A
    What is stretcher bond? I googled it and this is what I get: See pic 1Is that what U mean?

    Q
    No…not only at the corner. At every 3m c/c.
    For your wall height, no need intermediate lintel beam.
    Huh!....What did I suggest how the rectangular to be built?
    You want to have a round corner. There are many ways this can be achieved. You cab always built the wall up and have a piece of plywood cut to the width you required to chamber the corner and infill the with cement sand mortar (1:3). For a perfect rounding use plastering works to complete it.
    A
    OK!
    Thanks a million...Lots of advise I never new.
    Do I reinforce it under the plaster again? with a mesh or no need...Any advise on the plaster...remember no fiber or water proofing agent available here. What is the best way to do the plastering? Mixing proportions, thickness, application: one or two...any thing else?
  • NeliNeli December 2011
    Posts: 1,205
    Forgot the picture
    www.koianswers.com/discussion/download/5454/stretcher bond.JPG
  • harryyewharryyew December 2011
    Posts: 396
    Good day to you Neli

    Quote
    U said well drained ground condition...I think my subsoil is good.Do I add some sand on the bottom for better drainage?

    Answer
    Laterite itself is porous and tends to drain well. Temples at Angkor were built with it.
    No need to add sand for better drainage. It is already a good building material. You just need to compact it after you excavate it down. You still can use sand to do the final level adjustment. Wet the sand to compact if you do use.

    Quote
    What do U mean wall base.

    Answer
    Sorry bad wording. Please see drawing below. Can you understand now?

    http://www.koianswers.com/discussion/download/5459/cross%20section.jpg

    Quote
    column stiffeners?????Is that some thing that joins The column stiffeners to the blocks in the wall...Is it just a bar (bonding tie)...800mm long, tied to the column stiffener.
    Now concrete blocks if I am not mistaken are higher than 20cm...at list a bit...do I put that bonding tie between the horizontal block lines as I build each line of blocks?

    Answer
    Yes….it is column stiffeners to the block wall.
    Please see drawing below to understand.

    http://www.koianswers.com/discussion/download/5460/Wall%20elevation.jpg

    Quote
    What is stretcher bond? I googled it and this is what I get: See pic 1Is that what U mean?

    Answer
    Every time I mentioned something new….you will take the trouble to google and try to understand it before asking again. I like your attitude. Yes…pic 1. For the bottom wall which is a thicker section….you use English bond better. Sorry for the confusion. Here is a short description of the various brick bonding. http://www.fatbadgers.co.uk/Britain/Brick%20Bonding.htm

    Quote
    Do I reinforce it under the plaster again? with a mesh or no need...Any advise on the plaster...remember no fiber or water proofing agent available here. What is the best way to do the plastering? Mixing proportions, thickness, application: one or two...any thing else?

    Answer
    You have mesh there? Like this one http://www.taiwantrade.com.tw/MAIN/en_front/searchserv.do?method=listProductProductDetail&locale=2&MEMBER_TYPE=4&WEB_OPEN=&DOMAIN_NAME=&DOMAIN_NAME_FLAG=&company_id=266292&catalog_id=522235&come_soon=0

    If yes, you should install it at every course.

    On.... the plastering to the wall…….I have tried to install reinforcement mesh as above but in big pieces (600mm x 1200mm per piece). They have sharps edges and I find it cut the worker hands even I gave they them cotton gloves to wear. It is not practical for all its intended purposes. I have thrown it away. heheh…..

    So this is what you do…to get a good bond. Get a shoe brush and a small bucket. Pour cement powder into it and slowly put water into it until you get a neat cement grout and is homogeneous. Dipped the brush into the grout and stamped it to the walls at random at roughly 300mm c/c. Let it to dry in a day or two. For the floor, you pour the grout and use a stiff broom and spread it all over the floor [underline begin]when you are about to do the floor screeding[underline stop]. Remember to clean the floor before pouring the cement grout. Best is to use a high pressure water jet and jet it clean to your satisfaction.

    Wet the block works but do not immediately plaster…it is too wet and plaster mortar will drop. Wait for roughly 15min to ½ hour. The surface should be moist by then.

    I proposed a cement sand ratio mix of 1:2. Cement density is 1400kg/m3. Sand 1600kg/m3 dry to 1900kg/m3 when saturated. If it is wet you just take 1750kg/m3. Water cement ratio you try to use around 0.35 to 0.4. All mix by volume. You make a small box 300mm x 300mm x 300mm (0.027m3/box) and then use a shovel to count how many shovel to fill the box with sand. If the cement packing is 50kg/bag then for 1 bag of cement you have 0.0357m3. So…your sand volume should be about 2.5 box of sand. I let you calculate the water cement ratio. Hehehe….

    No day joint is allowed. You make sure you have the necessary resources and materials and a mixer is around. If don't have mixer make sure there are adequate general workers to mix. A skill plasterer should be able to do 1.5m2/hr easily.

    You direct them to plaster for a thickness of 15mm and skimmed finish smooth with a steel trowel with neat cement grout to a cement thickness off around 5mm. Make sure not too thin…like 2 to 3mm……it will experience localize shrinkage cracks or even spider web looks alike crack pattern. After 24 hours, you should continuously wet the surfaces with water for the next 5 to 7days. Best is if you have gunnies sack to wet and attach it to the surfaces. If don’t have use plastic sheet to cover the surface after wetting. This will minimize the number of trip to wet the surfaces. Do not allow air dry even on a cloudy day.

    If the plastered and floor screed surfaces are not level to plane and level. Don’t worry…you deduct the workers pays and when you infill with water…you will not be able to see the wavy surfaces. Hehehe……..

    Hope this is of some help to you.

    Cheers
  • harryyewharryyew December 2011
    Posts: 396
    With the revised reduced wall section....I calculate you should have a factor of safety of 1.5 which is still good in my honest opinion.

    Cheers
  • NeliNeli December 2011
    Posts: 1,205
    Hi Harry!
    It was my birthday on 25 12....so had 2 parties...was very busy...
    Here is a link to my party:
    http://www.koiphen.com/forums/showthread.php?127555-My-Xmass-birth-day/page2
    At list my sub soil is good.

    Quote

    Sorry bad wording. Please see drawing below. Can you understand now?
    I Understand, but can U revise it please! I want my pond to be 60-70cm above ground. Or is it the same? I think the stress above ground might be more?????



    Quote

    Yes….it is column stiffeners to the block wall.
    Please see drawing below to understand.
    A
    OK ! I understand...In your drawing they are drawn inside the blocks (some) How do I do that do I cut the blocks? Or just put them between the top and bottom block?
    We have here something called brick force. It is two parallel wires with a wire welded perpendicular at a 20-30cm distance...We put it under the blocks all around.
    Can I use that too and how?



    Got all the bonds now...Did not know about all of them. Do I use hollow blocks filled with concrete or is better to buy solid concrete blocks?
    Quote
    You have mesh there? Like this one http://www.taiwantrade.com.tw/MAIN/en_front/searchserv.do?method=listProductProductDetail&locale=2&MEMBER_TYPE=4&WEB_OPEN=&DOMAIN_NAME=&DOMAIN_NAME_FLAG=&company_id=266292&catalog_id=522235&come_soon=0

    If yes, you should install it at every course.
    A
    I dont have that, but have chicken wire, and I have some welded wire mesh (less than 6mm) 20x20cm squares, and it comes in rolls 25m long 2-3m wide.
    By U saying every course, I guess U mean brick force????? I meant something like a metal wire net put parallel to the walls and bottom and then apply plaster, so the plaster dont get cracks.

    Q

    So this is what you do…to get a good bond. Get a shoe brush and a small bucket. Pour cement powder into it and slowly put water into it until you get a neat cement grout and is homogeneous. Dipped the brush into the grout and stamped it to the walls at random at roughly 300mm c/c. Let it to dry in a day or two. For the floor, you pour the grout and use a stiff broom and spread it all over the floor [underline begin]when you are about to do the floor screeding[underline stop]. Remember to clean the floor before pouring the cement grout. Best is to use a high pressure water jet and jet it clean to your satisfaction.
    A
    Harry what is c/c? So I dont apply that grout solid every where but in patches 30cm apart?
    Q
    I proposed a cement sand ratio mix of 1:2. Cement density is 1400kg/m3. Sand 1600kg/m3 dry to 1900kg/m3 when saturated. If it is wet you just take 1750kg/m3. Water cement ratio you try to use around 0.35 to 0.4. All mix by volume. You make a small box 300mm x 300mm x 300mm (0.027m3/box) and then use a shovel to count how many shovel to fill the box with sand. If the cement packing is 50kg/bag then for 1 bag of cement you have 0.0357m3. So…your sand volume should be about 2.5 box of sand. I let you calculate the water cement ratio. Hehehe….
    A
    I will just use a bucket to calculate or better even...measure by volume with a bucket before mixing...I will calculate the percentage of water with the bucket too..That I can manage.
    Q
    No day joint is allowed. You make sure you have the necessary resources and materials and a mixer is around. If don't have mixer make sure there are adequate general workers to mix. A skill plasterer should be able to do 1.5m2/hr easily.
    A
    U mean I have to finish the plaster of the pond at ones? I can do that!
    Q
    You direct them to plaster for a thickness of 15mm and skimmed finish smooth with a steel trowe
  • NeliNeli December 2011
    Posts: 1,205
    Hi Harry!
    It was my birthday on 25 12....so had 2 parties...was very busy...
    Here is a link to my party:
    http://www.koiphen.com/forums/showthread.php?127555-My-Xmass-birth-day/page2
    At list my sub soil is good.

    Quote

    Sorry bad wording. Please see drawing below. Can you understand now?
    I Understand, but can U revise it please! I want my pond to be 60-70cm above ground. Or is it the same? I think the stress above ground might be more?????



    Quote

    Yes….it is column stiffeners to the block wall.
    Please see drawing below to understand.
    A
    OK ! I understand...In your drawing they are drawn inside the blocks (some) How do I do that do I cut the blocks? Or just put them between the top and bottom block?
    We have here something called brick force. It is two parallel wires with a wire welded perpendicular at a 20-30cm distance...We put it under the blocks all around.
    Can I use that too and how?



    Got all the bonds now...Did not know about all of them. Do I use hollow blocks filled with concrete or is better to buy solid concrete blocks?
    Quote
    You have mesh there? Like this one http://www.taiwantrade.com.tw/MAIN/en_front/searchserv.do?method=listProductProductDetail&locale=2&MEMBER_TYPE=4&WEB_OPEN=&DOMAIN_NAME=&DOMAIN_NAME_FLAG=&company_id=266292&catalog_id=522235&come_soon=0

    If yes, you should install it at every course.
    A
    I dont have that, but have chicken wire, and I have some welded wire mesh (less than 6mm) 20x20cm squares, and it comes in rolls 25m long 2-3m wide.
    By U saying every course, I guess U mean brick force????? I meant something like a metal wire net put parallel to the walls and bottom and then apply plaster, so the plaster dont get cracks.

    Q

    So this is what you do…to get a good bond. Get a shoe brush and a small bucket. Pour cement powder into it and slowly put water into it until you get a neat cement grout and is homogeneous. Dipped the brush into the grout and stamped it to the walls at random at roughly 300mm c/c. Let it to dry in a day or two. For the floor, you pour the grout and use a stiff broom and spread it all over the floor [underline begin]when you are about to do the floor screeding[underline stop]. Remember to clean the floor before pouring the cement grout. Best is to use a high pressure water jet and jet it clean to your satisfaction.
    A
    Harry what is c/c? So I dont apply that grout solid every where but in patches 30cm apart?
    Q
    I proposed a cement sand ratio mix of 1:2. Cement density is 1400kg/m3. Sand 1600kg/m3 dry to 1900kg/m3 when saturated. If it is wet you just take 1750kg/m3. Water cement ratio you try to use around 0.35 to 0.4. All mix by volume. You make a small box 300mm x 300mm x 300mm (0.027m3/box) and then use a shovel to count how many shovel to fill the box with sand. If the cement packing is 50kg/bag then for 1 bag of cement you have 0.0357m3. So…your sand volume should be about 2.5 box of sand. I let you calculate the water cement ratio. Hehehe….
    A
    I will just use a bucket to calculate or better even...measure by volume with a bucket before mixing...I will calculate the percentage of water with the bucket too..That I can manage.
    Q
    No day joint is allowed. You make sure you have the necessary resources and materials and a mixer is around. If don't have mixer make sure there are adequate general workers to mix. A skill plasterer should be able to do 1.5m2/hr easily.
    A
    U mean I have to finish the plaster of the pond at ones? I can do that!
    Q
    You direct them to plaster for a thickness of 15mm and skimmed finish smooth with a steel trowel with neat cement grout to a cement thickness off around 5mm. Make sure not too thin…like 2 to 3mm……it will experience localize shrinkage cracks or even spider web looks alike crack pattern. After 24 hours, you should continuously wet the surfaces with water for the next 5 to 7days. Best is if you have gunnies sack to wet and attach it to the surfaces. If don’t have use plastic sheet to cover the surface after wetting. This will minimize the number of trip to wet the surfaces. Do not allow air dry even on a cloudy day.
    A
    This one I dont understand:
    Neat cement grout to a cement thickness 5mm. Do U apply it immediately after plaster or that can be done the next day. And I have never seen that...What it is and how do U apply it?
    Here the way I have seen them do it is they apply plaster on the wall roughly, then they take a streightage (thats what they call it a straight plank) and start leveling the wall, then they do pronting (with a small flat wood with a handle), until the wall is smooth , they make it very level but it is not of the same smoothness as when they do the floor and sprincle rough cement on it and pront and smooth it with a metal pront..Is it supposed to be very smooth? like shiny smooth?
    Q
    Hope this is of some help to you.
    A
    This is of a great help to me!
    With all this explanation and advise I can project manage it my self and just hire builders to build. I can supervise it my self. I am scared if I hire a contractor...We might end up quarreling since he will not be used to build like that.
  • ShukriShukri December 2011
    Posts: 4,881
    I thought it was an abstract art........
    In Koianswers Forum, no one individual is above the rest. This is the Forum for the Koi Community.
  • harryyewharryyew December 2011
    Posts: 396
    Bro Shukri
    hehehe.....an abstract art indeed.... hahaha...

    To Neli

    Quote
    Here is a link to my party:
    http://www.koiphen.com/forums/showthread.php?127555-My-Xmass-birth-day/page2

    Answer
    Alamak!!!Cannot read. The message board return this...."You may not have sufficient privileges to access this page. Are you trying to edit someone else's post, access administrative features or some other privileged system?"

    Quote
    I Understand, but can U revise it please! I want my pond to be 60-70cm above ground. Or is it the same? I think the stress above ground might be more?????

    Answer
    Yes...I will revise for you. Do you want to design to scenario No 3 condition as in my earlier post? Scenario 3 is you don't have earth on the passive side but there is water in the pond. If not scenario 3, please let me know which one as it will determine how thick your wall will be.


    Quote
    OK ! I understand...In your drawing they are drawn inside the blocks (some) How do I do that do I cut the blocks? Or just put them between the top and bottom block?
    We have here something called brick force. It is two parallel wires with a wire welded perpendicular at a 20-30cm distance...We put it under the blocks all around.
    Can I use that too and how?

    Answer
    They are all inside the block and flush to the internal of the wall. You can either cast the concrete stiffeners 1st with the bonding tie and then lay your block works or alternatively you can always leave one block gap and use formwork to close up both side and pour the concrete in. Yes....proceed to use the brick force.

    Quote
    Do I use hollow blocks filled with concrete or is better to buy solid concrete blocks?

    Answer
    I think you used the hollow blocks and have Y10 reinforcement installed inside the holes and filled it up with cement sand mortar 1:2 as you move up. The reinforcement will take care of the bending forces.

    Quote
    I dont have that, but have chicken wire, and I have some welded wire mesh (less than 6mm) 20x20cm squares, and it comes in rolls 25m long 2-3m wide.
    By U saying every course, I guess U mean brick force????? I meant something like a metal wire net put parallel to the walls and bottom and then apply plaster, so the plaster dont get cracks.

    Answer
    You have brick force. They are equivalent. Don't use chicken wire mesh. They are hopeless. hmm....forget about those welded wire mesh of 20cm x 20cm grid.
    No. Every course mean every row of the block work. Yes...you place the brick force parallel to the wall for the full width of the wall and then apply plaster (cement sand mortar ratio 1:2) over it (about 10 to 15mm thick) and lay your next row or course of block work. The brick force is there to take tensile forces that may be generated from external forces and to prevent crack from propagating along the block works.

    Plaster crack can occur due to many reasons. Eg. Movement from ground settlement, thermal stresses, poor mix, improper application, loss of bond between the plaster and the block works.. etc to name a few. Do you have plastering "bonding agent" Check with your hardware shop. It is a white liquid like milk. See link http://www.pyeproducts.com/CCorks.php?page=sol

    Quote
    Harry what is c/c? So I dont apply that grout solid every where but in patches 30cm apart?

    Answer
    c/c mean center to center. Yes, you apply it patches 300mm c/c randomly. You can apply closer if you want. It is there to provide a good key for the plastering work to hold in position and provide a better bond between plaster and concrete blocks.

    Quote
    I will just use a bucket to calculate or better even...measure by volume with a bucket before mixing...I will calculate the percentage of water with the bucket too..

    Answer
    That is good. For small quantity, you can use the bucket and count but for mixing cement sand mortar on a bigger scale, it is better to work out the number of shovel of sand for a bag of cement of known weight. It will increase the mixing production rate.

    Quote
    U mean I have to finish the plaster of the pond at ones? I can do that!

    Answer
    Yes, in ones go, wall and floor together. I like your confidence. So..... tell me how the last portion should be plastered and floor screed and they guys can come out from the pond? hehehe...

    Quote
    This one I dont understand:
    Neat cement grout to a cement thickness 5mm. Do U apply it immediately after plaster or that can be done the next day. And I have never seen that...What it is and how do U apply it?
    Here the way I have seen them do it is they apply plaster on the wall roughly, then they take a streightage (thats what they call it a straight plank) and start leveling the wall, then they do pronting (with a small flat wood with a handle), until the wall is smooth , they make it very level but it is not of the same smoothness as when they do the floor and sprincle rough cement on it and pront and smooth it with a metal pront..Is it supposed to be very smooth? like shiny smooth?

    Answer
    Sprinkling dry cement and then using a steel trowel wet with water to create a smooth cement finish is wrong and it will crack for sure. If you go and see at close range when it is dry....you will see turtle pattern on the floor or spider web pattern. I have one project...the contractor challenged me to a bet of RM10,000.00 ringgit that I cannot screed steel trowel smooth a cement floor without the crack formation. I took the challenge and demonstrate it to them on site and he lost RM10,000 to me. hahaha...but he was happy because it saves him thousand of ringgit for all this remaining ongoing projects from having to continuously repair the cracks. I did not take his money but we all go and have a grandeur dinner.

    Yes, you apply the neat cement grout which is like a paste not immediately after the 1st coat plaster but about an hour later. No not the next day. Yes it is very smooth and when you rub your hands over it....no bleeding. hahaha....

    Your descriptions is one type of plastering work done usually to the external face. For internal walls over here we want it to be in plane, level, vertical and shiny smooth.
    Try watch this guy do it....



    Quote
    I am scared if I hire a contractor...We might end up quarreling since he will not be used to build like that.

    Answer
    Yes. That is usually how it end up. hahaha...... Yeah...my main contractor warn his supervisors, general workers, tradesmen and specialist contractors doing my pond.....go there and follow instructions...if not sure ask, if you have never done it before then declare and learn. Actually I use nearly 70% general workers who has no experience in this type of works but I am happy..... in the end the quality of works is outstanding including the soft and hard landscaping.

    Cheers
  • harryyewharryyew December 2011
    Posts: 396
    Hi Neli


    Back to your block work designs.

    Condition 1---- Assume that passive earth resistance is not there. i.e the earth behind the wall is loosely compacted and/or the earth there is excavated.

    http://www.koianswers.com/discussion/download/5491/cross%20section%20condition%201.jpg

    Using this setup you will have a factor of safety = 0.385 <1, The wall will topple.


    Condition 2---- Assume that passive earth resistance is not there. i.e the earth behind the wall is loosely compacted and/or the earth there is excavated.

    http://www.koianswers.com/discussion/download/5492/cross%20section%20condition%202.jpg

    Using this setup you will have a factor of safety = 1.3 >1, The wall is OK.


    Condition 3----Assume the passive earth resistance is there, i.e the earth behind the wall is well compacted and/or there is no excavation behind it.

    http://www.koianswers.com/discussion/download/5493/cross%20section%20condition%203.jpg

    Using this consideration your, Factor of safety =1.9 > 1, Ok

    You have expressed concern with the free standing of the block work above ground. As long as the height of the free water surface in the pond is not more than 600mm measured from the ground level.....your Factor of safety is 1.3. This is ok.


    You also make sure you direct your workers to plaster the back of the walls where the earth will rest against it.

    Cheers
    Post edited by harryyew at 2011-12-28 08:38:39 pm
  • NeliNeli December 2011
    Posts: 1,205
    1) When the pond is completed, earth is backfilled and water is infill.
    2) When the pond is completed, earth is backfill and no water is in the pond.
    3) When the pond is completed, earth is backfill and water is infill but later you excavate a substantial big hole near the external wall of the pond to build something or your neighbour dig a big hole at the back of the fencing wall.
    4) When the pond is completed, earth is backfill and water is infill, later your surrounding ground experience wet condition….say from continuous heavy rain.

    He he he! Harry, I saw the first sentence and thought this what U mean by condition 3...

    Q

    Condition 1---- Assume that passive earth resistance is not there. i.e the earth behind the wall is loosely compacted and/or the earth there is excavated.



    Using this setup you will have a factor of safety = 0.385 <1, The wall will topple.<br />

    Condition 2---- Assume that passive earth resistance is not there. i.e the earth behind the wall is loosely compacted and/or the earth there is excavated.



    Using this setup you will have a factor of safety = 1.3 >1, The wall is OK.

    A
    Harry I dont get it...condition 1=condition 2 (maybe U made a mistake?)
    OK! I got it...Conditions are the same but the base wall on 2 is 60cm thick!
    What is 50mm lean concrete?
    I build ones a double story shops....so I had plans for steel...I put all the steel my self and I was thought how to read the reinforcement drawings...But yours are nice and simple.

    Condition 3----Assume the passive earth resistance is there, i.e the earth behind the wall is well compacted and/or there is no excavation behind it.
    A
    I will do condition 3! U just tell me how to compact it. what about the pipes? There will be some pipes in the void....I saw somewhere to put sand there around the pipes...to prevent (dont remember well, but I think expansion and movement of the soil around the pipes)



    Using this consideration your, Factor of safety =1.9 > 1, Ok

    You have expressed concern with the free standing of the block work above ground. As long as the height of the free water surface in the pond is not more than 600mm measured from the ground level.....your Factor of safety is 1.3. This is ok.
    A
    Good! I will make it then 60cm above ground the water level, but the wall will be maybe 75cm, so I can put a window...with a reinforced beam of 15cm (no water) above it.

    Q
    You also make sure you direct your workers to plaster the back of the walls where the earth will rest against it.
    A
    Will do that. Thanks!
    Plan to make the pond 3.6m wide x 7.2m long and around 1.8m deep..
    Decided to reduce the size a bit since I was told that a BD sucks efficiently 1.8m radius..so in this case I can get away with 2 BD...
    I am making/redesigning the filtration of my pond, and will post soon for approval, as soon as I find some free time.
    Link to my 2 parties again:
    My daughter made the party for me at her house.

    http://www.koiphen.com/forums/showthread.php?127555-My-Xmass-birth-day
  • harryyewharryyew December 2011
    Posts: 396
    Hi Neli

    Quote
    He he he! Harry, I saw the first sentence and thought this what U mean by condition 3...

    Answer
    That is scenario 3. Condition 3 as in the post in this page refers to a condition where you will rely on the passive earth resistance to provide the counter balance force to make the pond structure stable.

    Quote
    What is 50mm lean concrete?

    Answer
    It is a concrete mix lean. eg 1:3:6. You just provide a working platform to work on.

    Quote
    I will do condition 3! U just tell me how to compact it. what about the pipes? There will be some pipes in the void....I saw somewhere to put sand there around the pipes...to prevent (dont remember well, but I think expansion and movement of the soil around the pipes)

    Answer
    ok. To compact it, you use the same method I have described earlier where you get all your workers to stamp and jog all over it and build 150mm thick layer by layer. Use granular material such as sand or laterite. During compaction the earth material should be moist and not wet until like a slurry.

    Yes, you can use sand to compact around the piping network routes and to mark the piping position. To compact sand you just spray plenty of water an let it soaked away to dry. It will self compact firm. Nothing to do with expansion and movement.

    Quote
    Good! I will make it then 60cm above ground the water level, but the wall will be maybe 75cm, so I can put a window...with a reinforced beam of 15cm (no water) above it.

    Answer
    No problem with 75cm. In fact the higher the better in term of counter balancing weight with respect to the pond water active force. The 15cm reinforced beam will give a good restraint and is desirable. I think do 20cm better. The exposed wall will be 80cm above ground and at 80cm that is a good height for one to sit on comfortably.

    Quote
    Plan to make the pond 3.6m wide x 7.2m long and around 1.8m deep..
    Decided to reduce the size a bit since I was told that a BD sucks efficiently 1.8m radius..so in this case I can get away with 2 BD...
    I am making/redesigning the filtration of my pond, and will post soon for approval, as soon as I find some free time.

    Answer
    BD sucks efficiently 1.8m radius? I don't think so. If you want to clear your pond fast then it is the turnover rate that is important. You need to have more BD pipes so that it can remove the fines and shit more efficiently while maintaining laminar flow. If you want Crystal clear.....you need sand filter to sieve up to 10micron of fines. I have made a modification to my sand filter piping work for backwashing and it is working very well. No need to use air pump. However....I have some small white feces-eating worms (around 5mm long) when I sample the water during backwashing. Are they beneficial or harmful?

    My pond don't have big koi shit at the bottom. There are some super fines there and that is if you try hard to look for it with underwater lights!!! hahahaha..... The swirling motion of the koi tails actually help to direct the fines to the BD. My pond turnover rate is around 1h.

    Cheers
  • NeliNeli December 2011
    Posts: 1,205
    Quote

    ok. To compact it, you use the same method I have described earlier where you get all your workers to stamp and jog all over it and build 150mm thick layer by layer. Use granular material such as sand or laterite. During compaction the earth material should be moist and not wet until like a slurry.
    A
    I will stump too! For best moisture content for compacting I believe is 12 %, or when U hold the soil it should form a ball, but no water should come out or make the hand wet...when quizzed...


    Quote

    No problem with 75cm. In fact the higher the better in term of counter balancing weight with respect to the pond water active force. The 15cm reinforced beam will give a good restraint and is desirable. I think do 20cm better. The exposed wall will be 80cm above ground and at 80cm that is a good height for one to sit on comfortably.
    A
    Good U clarified that since I thought U were stressing the point that I must not make it too high above ground.l

    Quote

    BD sucks efficiently 1.8m radius? I don't think so. If you want to clear your pond fast then it is the turnover rate that is important. You need to have more BD pipes so that it can remove the fines and shit more efficiently while maintaining laminar flow. If you want Crystal clear.....you need sand filter to sieve up to 10micron of fines. I have made a modification to my sand filter piping work for backwashing and it is working very well. No need to use air pump. However....I have some small white feces-eating worms (around 5mm long) when I sample the water during backwashing. Are they beneficial or harmful?
    A
    I also have a sand filter. What I saw in SA and I am going to do just now is this:
    U buy a compressor, Connect it to the backwash pipe outside the sand filter, by using the bolt (like pipe with threads and nut) for the back breaks of a car, when backwashing let the compressor run, The air comes out together with the water, and boils the sand, cleans it in 4 min, sparkling white...Normal backwash does not do much for a filter...It is a friend of mine that I went to visit, that invented that, and now every one does the same in SA. Before they used to connect the air to the arms inside, but of late he modified it and it works like this much better. In SA they sale special SF for Koi: the manifold is bigger for less restriction, the arms have larger holes and the sand used is 3-5mm.Also it is very easy to open...no bolt or nuts. Ones in a while, they open the lead and backwash the SF open...
    I plan to include it in one of the chambers (last) but make it like the american ERZ.
    Recently I discovered a new type of filter, vortex and bio at the same time using stereofoam beads...it is made and sold by a friend of mine Russel Peters...in US. I am now trying to redesign it, adapt it for use in a concrete chamber. It also removes up to 5 micron, and is much less restrictive than a sand filter.. U know the white packing material...like made of white beads? Thats the one...I wonder if U can adapt your sand filter to use them? They dont clog, and get bio on them too...easy to backwash and U dont need much water for it. But what I want to try....is the little plastic beads they use as a rough material for production of plastic items. They are somewhat buoyant and will do the job well.
    If U are using the SF as mechanical they do a very good job provided U dont allow them to clog. The white worms U have in your SF suggest to me that U have too much dirt in it. They help the heterotrophic bacteria break down the sediment.They are not bad....they are helpers... In France they use an insect, called ????cel....(I forgot the name) as mechanical filtration...buy it and put it in the Jap mats...it cleans them well. Get some of the worms and put them in your Jap mats....It will keep them clean, by eating any deposits on them...
    BTW, it is not a must one hour turn over...it is a luxury...I know many ponds that function well with a 2 hour turn rate. Just that the pond needs to me designed well. For stream flow U need one hour, but not for circular...
    I have ordered today 20 ton quarry dust and 10t river sand...starting to prepare all the materials for the pond. They have just delivered the first load... Want to stock pile all the materials. get/prepare every thing and then start...Still need to do the plan, but maybe in the new year....too busy now.I will make the plan step by step before I start or I will forget half the things U told me.
    If I add more drains to the pond, it will interfere with my flow...I dont plan huge turn over so 2 BD are fine for me.
    Q
    My pond don't have big koi shit at the bottom. There are some super fines there and that is if you try hard to look for it with underwater lights!!! hahahaha..... The swirling motion of the koi tails actually help to direct the fines to the BD. My pond turnover rate is around 1h.
    A
    What are U feeding the Koi that they dont have big shit? He he he! When am I going to see your pond and Koi?
  • NeliNeli December 2011
    Posts: 1,205
    Update on my ugly babies...first and second spawn.
    If any one knows what are the chances of them becoming any recognized variety...please advise...I have no idea what they will turn into but I am having lots of fun!
    The first ones are now 4cm long, and the second are reaching (some) 2 cm... I put them all in the intex...
    I know the Japanese cull all white fry for showa...but I was wondering if the black fry they keep looks anything like this?
    When does any color show on fry?
    This two sets of pictures are 3 days apart....they doubled size in 3 days...
    www.koianswers.com/discussion/download/5498/024 (640x279).jpg
    www.koianswers.com/discussion/download/5499/133 (640x630) (2).jpg
    www.koianswers.com/discussion/download/5500/118 (640x480) (2).jpg
    www.koianswers.com/discussion/download/5501/083 (589x640) (2).jpg
    Some one on facebook told me they look like rejects...He he he!
    And is probably right, but I am grooming them for grand champs!

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