Silo for pellets and resistance screed

[Obamot]

Well, it's useless to ride your big horses, no insult to you (I said: "If a braquaillon read you" etc. Do not feel targeted for so little ...)

The hedgehog is the bottom of the concrete: crushed tiles, bed of pebbles ... etc.

... and spreading a layer of lean concrete over it!

it is not worth asking the question if the soil is hard and the sledge (hedgehog) is done in the rules of the art (as they say).

... it is not enough that the soil is "hard", the most important is that it is homogeneous. It is better such a soil, a soil with "hard" parts, but not homogeneous ....:

http://www.francetv.fr/info/l-effondrem ... 55429.html

Good evening;
I seem to have made no confusion ..... [...]
I therefore maintain that placing the 4 feet of a silo 5T on such a slab is not a problem.
I built my silo in the basement without BE in accordance with the usual rules of construction. No trouble.

... no trouble if "homogeneous" soil, otherwise, with a load of several tons, which "moves" with time, there may be local destabilization.

If we are dealing with a "write off"(But I did not go there) do not forget to add all the weight of the construction that is above, (+) accidental loads and other safety margins (+) the 5 tons punctual distribution!

Added to this are the local frost conditions. There this point is not clear (it is said above that it is in the basement, but it also speaks of "garage" ... so point to watch ...)

What can be done afterwards, to know if the ground is homogeneous under the raft foundation? What about local conditions => immediate proximity to a body of water, a water table, a watercourse => wet soil? Who does the drainage? Is the ground around it level? Or on a hill? Does the current construction show any cracks? Where? Of what importance? If so, is there the possible presence of a significant sloping roadway? How important is heavy-vehicle traffic? (Vibration, runoff water) etc ...

Which company made the construction? Have there ever been extensions to this construction? How has concrete been implemented? ... Many questions that deserve reflection and that I see absent from your remarks ...

You see, nothing is simple in the BE .. What slices with someone behind his keyboard and does not engage his legal responsibility if he omits some "details,", Since entrenched behind the anonymity offered by the internet.

In addition to the study of all these parameters and precedents, I remain on the solution of Ahmed (distributed load).

And the silo is 5 tons spread on 4 points, it's still the weight of five mini-bus like Toyota Hi-Ace, so I suggest to put half of the load the first year, just to stabilize the ground, if we do not know exactly how it is done below ... By precautionary principle.

[Did67]

I'm scared to read a number of inaccurate things about concrete!

Some seem to confuse everything!
1) CP 250Kg /m3 (and not m2) is the dosage of cement in concrete (CP = Portland cement). From 250Kg / m3, we are dealing with a high dosage (resistance in tons / cm2)!
.

Mr. Engineer,

Allow me to point out that you are going fast by taking your interlocutors for fools!

Imagine that without being a "structural" engineer, it may be that some people have a minimum of culture or ... practice or even that they are engineers too, without spreading their culture like jam ... Pardon, their title as "I am therefore necessarily right" (the quintessence of the engineer: to be right!).

So the dosage of cement is one thing. Certainly. Nobody talked about it.

But it seems to me that the lift (since this is the term seems to me) of a reinforced concrete floor of 10 cm thickness made in the rules of the art is ... 350 kg / m². So a slab in a building (for example an immueble, a school) is calculated to support 350 kg / m² (in principle uniformly distributed).

Or am I mistaken, sir?

This is the figure that I evoked, for my part, plus hat, pointing out that we did not have this scenario since the concrete resting on the ground ... So the same slab will then carry much more, since there is no lift on a vacuum.

[Did67]

In this case (without technical vacuum below and a concrete poured in the rules of the art, as described above) it could resist very well to the compression [/ color], you could load without much problem, the only concern is the ground, if there is subsidence, you risk cracks / micro-cracks that will not be visible (since located opposite the location where the load will be) with risk of rising damp even flooding in severe cases. But these are extreme cases.

.

Strange, but without bringing back my serious strawberry, it seems to me that I did not write something else fundamentally.

But since the Engineer says it !!!

I would just add: in practice, in a private house not new, it is extremely rare that a slab is not cracked, or that there are no side gaps along the walls, or even parts in natural earth, and so that if there is a risk of flooding, our interlocutor would probably have realized it.

But as the Engineer says, you have to check: for example to drill a hole with a perforator and see if there is flood (sometimes there is a doubt).

Mr. Engineer probably has to work on specific projects like underground parking in cities with water tables, etc ... but as it is too modest, it does not stuff us with that!

[Did67]

...

Finally, although I think a silo is a good solution, in this case the load is redistributed on 4 poins, while without silo, all the load is distributed on the ground. And again, impossible to validate anything "to the good franquette" (since no knowledge of the local configuration ..) to everyone to take responsibility.

Be careful, do not go out, you'll get cold!

100 000 pellets heaters in Germany, 30 000 envrion in France, I am the question of prep: I do not know any case of collapse of silo (textile or not) or upwelling ...

I doubt that in the least case there was a study of the structures. People have installed a silo, basta !!!

But I think we should filter the air outside, there are viruses right now!

[Obamot]

So the dosage of cement is one thing. Certainly. Nobody talked about it.

But it seems to me that the lift (since this is the term seems to me) of a reinforced concrete floor of 10 cm thickness made in the rules of the art is ... 350 kg / m². So a slab in a building (for example an immueble, a school) is calculated to support 350 kg / m² (in principle uniformly distributed).

Still wrong

As already mentioned above, the concrete resists much better than that with the compression: in this case it is in Kg /cm2 (and not m2). It is necessary to count 230 Kg / cm2 for controlled concretes to 28 days * for CP300Kg / m3 (this is a logarithmic scale, and therefore the resistance continues to increase over time) ...

I agree that I am pessimistic. This is my job, given the little real info we have. Other than that, I feel that I have not taken anyone

* determined in laboratory tests by cubic or prismatic test pieces, subjected to destruction tests, made with the concrete manufactured on the site, under identical conditions of implementation, the day of casting of the slab ... And yes, in today's day it becomes sharp, my good Môsieur ....

[Did67]

I reiterate: a reinforced concrete slab to standards such as the floor of a house, the floor of a school, so a concrete slab on the vacuum, is calculated to withstand a load of 350 kg / m²; so for example 350 kg of people evenly distributed on the 40 m² of the classroom with below another classroom or technical premises that holds ... It is good kg and m².

Is it true or false? (I'm pretty sure - but not a construction engineer)

Is this called lift? (I'm not sure at all, but I wanted to point out that it was not compressive strength - even without being a BTP engineer, I know about samples drenched in water during 28 days that one crushes, which is quite another thing, I agree)

[Do not make any effort to understand the blissful language of non-technicians and utter "it is false" without trying to understand, it is not the sufficiency of engineers ??? Finally some! Call it whatever you like. It is in any case a mentality. That I often come across in my work - we are finishing a heavy rehabilitation, I could tell you about the bullshit of the BET and architects, just because they are the only ones who know and do not know how to listen to the users, who are considered just as fools. And I found it 100% here, your last and peremptory "it's wrong" is the illustration if a third one was needed]

Again, answer the following questions and forumThey will judge:

- on a reinforced concrete slab, which is up to standard, on the second floor of a high school, I can put which load uniformly distributed per m² knowing that below there is another room, the slab above being the ceiling of the room below ???

- what is this called in technical language?

[dedeleco]

The slabs on a crawl space are complex, with an insulating slab below, resting on prefabricated reinforced prestressed concrete beams and a thin slab often above 5 to 10cm thick, which support some 100KG to m2, depending on the strength of the beams. .

Slabs on ground are much simpler and support especially what supports the soil.

If the house is old, has it supported the drought of 2003, without cracks ???
Basic test on its soil and the quality of its foundations !!

If no cracks or damage, then no problem with the slab that with 5 tons to distribute, will bear much less than the weight of the blocks much more than 10 tons on the gables in blocks.

If the soil is bad, a few cracks in the walls, following 2003, then the slab will crack a little, even without anything on it, for tens of years!

Finally if the ground below may freeze then disaster assured, also for the walls all around well before !!!!

[St1ngy]

J
- on a reinforced concrete slab, which is up to standard, on the second floor of a high school, I can put which load uniformly distributed per m² knowing that below there is another room, the slab above being the ceiling of the room below ???

- what is this called in technical language?

The "weight" is in fact a force in N (newton) but we make the approximation 1dN = 1kg.

So in a school: we take into consideration for calculations
- the weight of the structures
- permanent loads (tiling, library shelving, platform, bleachers ...)
- operating expenses (people, books ...)
- climatic loads (wind, snow ...)
- possibly earthquakes.

In general and according to European countries, school type structures are calculated for operating loads between 3 & 4 kN / m2. i.e. 300-400 kg / m2.

[manet42]

I come back to the subject because we move away from the question ....

It is not a slab with slabs and vacuum below, payload 250 / 300 daN / m2, there we are all OK.
It is a standard reinforced concrete slab on ground with hedgehog. It is much more resistant.
Compression strength figures are given according to the concrete class, made on specimens (cubes or cylinders); megaPascals / cm2. They are very far from in-situ values.

All this to conclude that a silo of 4 / 5t on 4 feet placed on plates of 10cm / 10cm does not pose a problem.

Moreover, I do not understand why Obamot says to take into account the walls above .... At my house there are the foundations, the walls put on them and then we poured the slab of the basement (hedgehog + lattice) between the walls so not solidary ...

JC

[Obamot]

I have not concluded that, and I explain myself one last time.

(If however you do not understand, read the PDF).

I was also talking about a slab on the floor, I even say that we need to spread lean concrete on aggregates or all-comers ... etc. In short, no floor slab!

I understand what everyone has written in each of his posts. It's not wrong and at the same time, these are just "punctual truths"!

I'm not going to talk about the silo again, I've already said everything. Moreover, look at the contradiction of the numbers brought by one and the other: in one case some say 350 Kg / m2 while in others we come to a little over a ton on a square of 10 x 10cm ...! I do not really know what you want to deduce ... We must put everything back flat!

Regarding slabs on support
A concrete slab does not support anything in compression (except in the upper central part, but that's not essential) and especially not in the center of the traction zone far from the supports! All efforts are absorbed by the frames!. It is therefore important not to focus on this data load (purely theoretical since we can not admit that it is the same / or equally distributed on 40 m2 ...) A correct index is given by the loads listed by St1ngy to which we should add the rest, including "accidental charges».

The limit of load imagined by Did67 is thus very theoretical (if it is that of the limit of which it speaks) since they are not the same in the center in the critical zone or close to the supports!

Thus, what matters is not the loads, but above all the admissible stresses, which determines the computation of the forces of sudden pulls by the reinforcements: yes it is the reinforcements which absorb the majority of the stresses on a slab, by the compressive strength of concrete! Therefore we are in a system of hyperstatic construction and we can not / more set "standards" applicable to all cases, as said very well Dedeleco: it is complex, recalling the episode of drought of 2003: know that only the expansion coefficient is 12 (x) 10 power -6 (for 40 ° C, ie -20 ° C to + 20 ° C).

Another example: do we have floating or embedded slabs? Because here too, the data of the problem changes drastically, since the embedding angle undergoes no deformation ... The charges are therefore pushed elsewhere and the frames are not in the same place ...

In short, it depends on everything! To answer correctly, it is necessary to make a complete inventory of the constraints for the work in question.

By way of example, they may extend as follows:

Actions: basis of calculation

5.1 / Definitions

Actions are forces or couples directly applied to the construction. They can also come from deformations imposed on the structure such as dilations, settlement of supports, withdrawals, etc.
The values ​​of each of these shares are nominal, ie they are known from the outset or given by regulatory or contractual instruments.
They are therefore the basis for assessing manufacturers' obligations as well as user responsibilities.

5.2 / Nature of actions

Consider the schematic section of a building:



Legend:
1 - Facade wall
2 - Shear wall
3 - Concentrated charge
4 - Wind Action
5 - People
6 - Furniture
7 - Land Surge
8 - Reinforced concrete floor
9 - Partitions
10 - Temperature
11 - Floor covering
12 - Reinforced concrete beam
13 - Automotive
14 - Water underpressure

All these actions can be classified as permanent actions of constant intensity or very little variable, and in variable actions whose intensity varies frequently and significantly over time. We can still break down these permanent and variable actions.

• Permanent actions:

- the loads brought by the self-weight of the structure: these are, in our example, the 1 and 2 loads due to the walls of facades and sheds as well as those brought by the 8 and 12 reinforced concrete floors and beams.
- the loads brought by the weights of the other elements of the construction: these are the loads brought by the 9 partitions, the 11 floor coverings, the cover and the equipments
fixed.
- outbreaks of 7 soil and potential liquid pressures such as water underpressures due to groundwater levels 14.
- actions due to deferred shares, such as shrinkage by shrinkage of concrete in the 8 reinforced concrete floor.

• Variable actions:

- operating expenses such as 3 concentrated loads, 5 persons, 6 furniture and 13 automobile.
- the climatic loads fixed by regulatory texts such as 4 wind or possibly snow.
- the loads brought in the course of execution which come from the equipment of construction site not visible on our example.
- the temperature actions due to ambient variations during the 10 day.

See the diagram on 5 page of this PDF:

http://www.coinduprojeteur.com/cours/le ... 20arme.pdf

Without reinforcement we would have superstructures of types: vaults or domes, otherwise everything would collapse when we exceed its limit of elasticity (very low, since the concrete has a very low elasticity).

So even for this slab in the basement, as long as we did not make a complete inventory of ALL the constraints. We can not say anything definitively.