Niveau à laser: How to leveling w/crossed line laser level?

[dedeleco]

In one turn, it moves up around 1cm and with a iron bar of 60cm inside the handles, pushing hard with hands on this bar with a force around 30Kg moving on a circle of diameter around 1m, this force of 30Kg with hands, move of Pix1m=3,14m for moving up of 1cm, so the level ratio is around 3,14m/1cm=314 !
Thus the up force can be of 30Kgx314=9,42tons
if there is no strong friction inside the screw, which is prebented with grease put before inside the screw of theses props .
Thus it is sure that you move up several tons with this inexpensive method, that I have used in the past, !!
The maximum weight on theses prop is typically 2 tons officially.

[dedeleco]

With the help of a cheap truck jack 12tons, and many props, you can move up all the house.



Be very careful to know the order of magnitude of the weight of the house and to move all the pilars up together slowly !!

[dedeleco]

two relay antennas was erected by mobile phones operator (or/and Radio-TV), but they seemed to be not impacted by the flood (but we have to checking this out again).

Very likely, they put good pilars underground at tne right depth under the antenas, which are less heavy likely.

It appear on this draw, that some part is missing to represent a perfect parallelepiped. That tell to me, according to the type of the land, we have here the cause of the imbalance. Reason why the house is prone to be unstable,

more likely, for any shape, the underground is not homogeneous, and this is sufficient to moving down more on some side of the house.

It is like the Pise tower in Italia !!

Another reason is maybe some exceptionnal flood for about one month and a half (in the last november). Or maybe not, because it's the normal state for this land!

Very likely, it is the normal condition for a rich rice land, with flooding for rice !!

At what depth are the shoes or foundations under the 14 pilars and what length have the pins under theses shoes.

If less than 2 meters, it is not surprising, foundations must be made by searching the good strong ground or very long pins after a serious geological study of the ground.
What is the real weight on each pilar ??

[Obamot]

Yes, I read carefully what you wrote, also the last page, and I'm agree with you about the pilars. I think, by evidence, they are too shorts pins. But we have to wait a tad to go conclude something right now. Because of the lacking of some parameters.

R&J (the owners of the house) will also read your previous post about the props with interest. It's something like that, what I was suggested to them (third step), on the previous page (point fourth):
https://www.econologie.com/forums/post230180.html#230180

Not exactly but your idea of props, make sens...

Ok, here we are: go to find parameters, and determine, what are the possibles causes? As we know (some points from you):
1) assymetric design for such a ‘floating house’.
2) an asymmetrical transmission of the weight to the land which brings. down the house by the heavier side.
3) some zones of the land are more soft and light than others, which attract the house down side.
4) and of course, a wrong calculation of the structure by the engineer (undersized foundation).
5) OR – as you noticed – resistance of the mud with piles insides has been overestimated.
6) a disturbance that came by the flood and only by this cause.
7) some movements of the water mass underground, because of its own caracteristic (affected by the water table and not directly by the flood).
8} the house is "naturally" prone to go deep (because of the undersized foundation, but not according to other cause/s).
9) a combination of differents points above.

So, from this night, I know that the house begin to go down side BEFORE the flood. So, we both agree many of these points, and the fact that is «the normal condition for a rich rice land, with flooding for rice»

About your proposal, a "test load" will be indispensable for knowing the distance between the house and the stable ground. (if it exist...)

In the other hand, to know if we can put a counterweight (or something, and if the foundation to the opposite side are well builded), we must need to know some points:
— if the foundation and the beams structure can resist to this treatment.
— if so, what weight can we add so place, without any risk to the structure.
— subsidiarily, adding more foundation is possible (thanks to the girder system) but it will still determine the exact size.

Because, since we known that the ground is soft, the problem for your two suggestions above is: there is no "bearing point" directly available right now. If so, we must therefore create it from A to Z, enlarging foundation or something: and that have a cost!

By the same way of you, the contractor suggest to use an hydrolic leveling system. But again, that would not solve the causes of the problem.

Moreover, I will remember you that there is no budget for build such a bearing. And this bearing need to be strong, because the leverage concern much more than the weight of the building! But if we admit this as the only solution available: the addition/multipication of forces (inertial moment or whatever), regarding to the transfert of charges: using hydrolic, lift up some part of the house OR add some weight to the opposite side, would producing same efforts to the structure.

But first of all, we have to determine what is the right leveling. That will give better information about the causes....

[dedeleco]

I agree.
First, it is necessary to estimate the weight of the house and its pilars, all concrete, or quite a lot of wood ???

Second what are the depth anf number of pits under the shoes ??

third , what is the strenght of the ground as function of the depth?

It is possible to evaluate by pushing a simple very long iron bar with a simple heavy hand hammer up to the maximum depth in order to know the necessary depth of the pins !!!

When the ground is soft, it is absolutely necessary to push many strong pins or pilars inside the ground so that it never can move by reaching the hard ground or if not possible by friction on a very long surface inside the ground.

This is classical in particular for very tall buildings.
I remember on a video on a very tall buiding in Shanghai on a very soft mud !!!

In this case, of simple house, it is possible to remain cheap, by pushing very long thin bars or tubes very deep inside the ground (10m or more) with hand hammers so that, the number of theses pins times the force of resistance measured for each pin, is equal to the weight of the house on the pilar. Even by hand hammer, it is possible to reach a resistance between 0,1 and 1 ton for each pin or simple tube if sufficiently long.
With tubes it is possible to push cement inside to the depth of the ground, with some air pressure.
This can be made cheaply by hand .because the ground is free of access around each pilar.

After, on this strong base around each pilar, it is easy to move up the house, with only the hands and cheap props and one jack.
I have made such moving up in the past on a heavy wall.

If nothing is made, all the house, will move down surely without any end and cracks slowly many times and be destroyed.

It is absolutely necessary to stop this movement.
It begans dry before the flood, proof that it will be endless !!!

For short times, when the ground is dry, it is possible to put very large surface of metallic iron thick plates on the ground and with many props on theses plates to push up the house or at least stops the movement down inside the ground, the plates moving down inside the ground at the place of the house, compensated by turning up the screww of the props, each week !!.

It is the minimum to make at short time, before pushing down many pins or pilars deep inside the ground, which, otherwise, will "eat" all the pilars of the house endless, betwwen wet and dry seasons !!!

[Obamot]

I agree.
First, it is necessary to estimate the weight of the house and its pilars, all concrete, or quite a lot of wood ???

No wood at all (what you saw is traces left on the molding of the concrete by the wood.)

(1) We already have an estimation of the weight: as already reported, is 8T per pillar for a total of 112T including the roof. That tell to me, it will be not less than 45 m3 of concret (but a new calculation is urgently required, because of this problem, for sure)

Second what are the depth anf number of pits under the shoes ?

(2) I agree too. They don't know exactly, anyway, we can't change that. So we need to do with it. But no problem we need to care about that point, as a parameter of the problem.

what is the strenght of the ground as function of the depth?

(3) Same thing, they don't know exactly, we can't change that. By the way this parameter change all the time: sometime it's about 80cm to 1m of water under the house (coming from the farmers because of rice plants) sometime more about rainy season, but generally they add water willingly, taken from the river for fishing (and of course doing fish!). Because primarily, bathing inside the water is the goal of this house:



As you can see on the photo above, the level of the water here is extremely low... The maximum level can be in the middle of the pillars. And what you see around the pillar, is the footings of the foundations, supposed to be stable and strong ground...

Again we need to care about that point, as a parameter of the problem.

It is possible to evaluate by pushing a simple very long iron bar with a simple heavy hand hammer up to the maximum depth in order to know the necessary depth of the pins !

When the ground is soft, it is absolutely necessary to push many strong pins or pilars inside the ground so that it never can move by reaching the hard ground or if not possible by friction on a very long surface inside the ground.

This is classical in particular for very tall buildings.

Yes, but it's NOT a high building, but an assymetrical flat design.

So, could I suggest a «minimalist step by step» way to do? And using the material available on site, because of an ecologic concern (water... land... rice... because rice can drink A LOT of water to growing up => and give a temporary answer to this question... if not for ever...!)

I repeat, it's maybe to early to conclude. Because if the house tend to go only one side, as you can see here:



... it's eventually only because of it's assymetrical design!? If you follow the red line on the photo. Maybe we have the chance that the level to right was never moving (and move only to the left). If yes, we only need to fix the problem to the left (beginning to the right by adding some props and them temporary footings), and at the same time 1) stopping the progression to the left, with one or two props, attached to the end of concrete beams, and who takes his seat on the footings of the lobby and/or temporary footings 2) add some pillar too (between the existing footings), but more than to the right (after the new evaluation of the weight of the house if so...).

By the way, the answer is add pillars and footings everywhere between existing foundation.

In this case, of simple house, it is possible to remain cheap, by pushing very long thin bars or tubes very deep inside the ground (10m or more) with hand hammers so that, the number of theses pins times the force of resistance measured for each pin, is equal to the weight of the house on the pilar. Even by hand hammer, it is possible to reach a resistance between 0,1 and 1 ton for each pin or simple tube if sufficiently long.
With tubes it is possible to push cement inside to the depth of the ground, with some air pressure.
This can be made cheaply by hand .because the ground is free of access around each pilar.

Not a bad idea at all. As you understand at this point, I notice the urgency after reading your posts and I changing my idea about priority. Now, I would suggest:
— props on temporary footings, for stopping the descent (at the lowest side)
— at the same time, as I already suggest, a propice zone to use the footings of the lobby/corridor to put two others props (in the south-east part but same side) to expect the same effect, as you can see on the photo-montage above (see the magenta arrows).

(but yes it's not suffiscient, in the south-west side, reason why I suggest temporary footings.)

So it's four pops, for a total of 8T or 12T as a minimum (32T as a maximum)

Then if that give good results: it's necessary to put definitive small columns and extend the footings as soon as possible with reinforced concrete.

Conclusion: If other solutions dosen't work. So yes, we can add more pillars (thanks to the grider system).

After, on this strong base around each pilar, it is easy to move up the house, with only the hands and cheap props and one jack.
I have made such moving up in the past on a heavy wall.

If nothing is made, all the house, will move down surely without any end and cracks slowly many times and be destroyed.

It is absolutely necessary to stop this movement.
It begans dry before the flood, proof that it will be endless !

Yes, exactly! But adding other pillar tell me it's better than doing something with the wrong ones? (Who they can stay "as they are".)

For short times, when the ground is dry, it is possible to put very large surface of metallic iron thick plates on the ground and with many props on theses plates to push up the house or at least stops the movement down inside the ground, the plates moving down inside the ground at the place of the house, compensated by turning up the screww of the props, each week !

Well, I'm not on site right now, and people over there are not engineer technician at all... It's a delicate mission! And finding the required material is not like in France or Switzerland, not easy at all.

It is the minimum to make at short time, before pushing down many pins or pilars deep inside the ground, which, otherwise, will "eat" all the pilars of the house endless, between wet and dry seasons !

Yes, it's risky. They have to do something as soon as possible. For sure.

But before again, a diagnosis need to be done, to check the leveling. That make sens to find the real causes.... And also to have some referenced points to control and compare hypothetic future changes of level.

[Obamot]

Here a scheme, that show why the center of gravity would move in a non-uniform fields.

Especially when the design is asymmetric.



When a "missing mass" (down the left in pink) would change the presumed barycenter !

[Obamot]

At this point and before the leveling step:

– here a brief synthesis according to what is known – or not – of the situation.

Known (in twenty points)
1) The house was built from about 1,5 year ago.
2) The house began to sink slowly into the ground, and a flood seems to be accelerate this (or not much, that we have to check first).
3) The house is a tad inclined (tested with a metallic ball and appear in photographs).
4) The inclination is about 0,5° if I'm not wrong (Go down 10cm for a distance of about 1300cm of length).
5) The house continue regularly to sink, slowly but surely in one side (if not all the house?).
6) The pillars and footings can theorically resist to a weight of about 8T each (or is calculated to resist to 78,45 kN each).
7) The calculated barycenter (according to the foundations) is off center OR/AND the ground is not homogenous.
8} The calculations of the engineer was not sufficient. And don't take account of all parameters.
9) The design of the house is not a quadrilateral, and this imbalance is surely a part of the problem.
10) There is no slab, but a girder system. And this can help to fix the problem by different ways. For example by adding more footings, columns (or props, like here: see the red arrows ...>) close enough to existing column, under the beams (but near the support, for exclude an overload. And the summit of column can be reinforced and wider than the body, like here ...>)
11) Founded on the previous point, some temporary actions to fix the problem may be taken quickly, without risk to the structure. Thanks to the elasticity of the land.
12) If nothing is done, it is possible that the house continues to sink until touching the ground.
13 As reported, the repairs should take account of a land often waterlogged.
14) An hydraulic system is not a good idea, because this method do not solves the causes of the problem. By the way, there is no guarantee that the house will remain stable once adjusted ... And we can do the same by using gravity.
15) At some point, we can also utilize counterweights, if moderate (not more than that the maximum regular load, added of exceptionnal load ratio) and if everything is ready to enlarge footings first.
16) Antennas of some mobile phone operators behind the house seems to be not affected (but that point need to be checked).
17) Sooner or later, walls and pillars need to be tested: to determine their resistance and prevent a collapse (of all the house)! Because if an engineer forgot something like this, it can forgot more.
18} No budget for repair (or few). That tell to me: choosing precast reinforced concrete footings and preps seems to be the way to go? (And of course, find a solution according to the existing structure.)
19) If wider temporary footings dosen't fix the problem: for final solution require finding the strong ground or choosing long pins after a serious geological study of the ground OR having the proof that wider footings are sufficient to support the house on this type of soil.
20) It's necessary to (re)calculate the actual volume of concrete – adding to the weight of the roof – to determine the real weight of this house and the size of wider footings and new columns.

Unknown (in one point)
Everything what explained on previous posts! By the way, how can I list something I don't know?

[Obamot]

At this point, the facts tell to us that we have probably a combination of two reasonable hypothesis. The first one could confirm the second (or not if the action to stop the sinking in the down side, would give the expected result).

First cause: size of footings are underestimated in one side
The house had a wrong calculation of foundations footings because of:
– an assymetrical design concept.
– so the "missing mass", would displaced the presumed location of the barycenter (that is probably – but surely – the first big mistake of the engineer).
– then the house is in a state of imbalance. and would descend because the land is soft and for to achieve the balance point with his real barycenter!
But we don't know if it's the only cause right now. We must stop the sinking one side, for to know if it's "true or false".
That tell to us: we must take temporary action to stop the sinking in the side concerned to validate this hypothesis.
– If it's true, the house could stop in this position OR/AND interacting to correct his position, thanks to the new repartition of the weight, and could leveling himself horizontaly by the help of terrestre gravity (or not but we can obtain the status quo. By the way we can add some counterweight and so on...).
But I think, this hypthesis is true, because many points already confirm it:
a) the sinking is exactly in the side concerning by this hypothesis.
b) by visualisation of the map, we can see also, that the maximum weight of the house, going to appear in the same side.
c) by testimony, it appear that the size of the footings are the same everywhere, when they should be of different sizes, since that the distribution of the load of the building is not the same everywhere...
d) the repartition of the footings, by numbers and them positions, going to the same conclusions.
e) also the tilt axis of 0.5 °, going directly from the lightest part of the building to the heaviest part ...
f) it would be an incredibly bad coincidence, that with a weight of about 112 tons, the building going sinking exactly where it looks to go (because of its centroid), by pure coincidence of vagaries of an unstable ground... (Not to say that the odds are very low, because of the basic laws of physics, recalled by Dedeleco).
But we have to check it. And we will do it.... with help!

Second complementary cause: resistance of the land was overestimated
With the combination of the first one (wrong estimation/calculation of the barycentre location), this second hypothesis is the worst (if so...). Because (if true) it adding to the assymetrical problem of sinking, because it's the proof that the foundations pins and footings, are not sufficiently wide and long to support the complete weight of the house. And this, footings by footings.

That tell to us: the resistance of the land – often waterlogged, and inside pillars... – has been overestimated. And whatever we do for stopping (by enlarging footings), the house will continue to sinking by his own weight, until footings touch the real ground (but we don't know when this can happend, if it's more than two metters, and at the actual speed of sinking, the beams can touch the land in 15 years or less...).

This hypothesis are already true for a small part, But we don't know how really huge is the problem, because of lacking of informations.

Because of the urgency, the owners of this house, must do something to fix the problem. Without providing more damage to the structure: and also to prevent and limit the actual damages (that appear already by very small cracks) and stopping the progression in a near future.

But if we do by empirism without budget, we must confirm all these hypothesis. By the action (to stop sinking), and noticing what is the interaction. With a true precision!

The leveling of the house will confirm (or not) some hypothesis.

[Obamot]

According to the above (and if true).

Here a suggestion of a minimalist solution:



After we can discussing if a counter-effect could appear or not!? Theorically yes, according to the calculation of the "moment" of inertia (an evaluation between 25 and 50 kN?). But we really don't know actually, and it can takes time (to interact)! But that is not really a problem imho...

So, now is the time to do the leveling...


Important NB: here, the cutaway is an "egyptian representation". To be true, all the extra footings & columns would appear in the respective perpendicular sections. This is only to show the principe of this strategy.