drilling base plate mounting

[gil]

Hi.
As a result of a lively discussion I would like to ask you this question.
take for example a metal frame with base plate as from drawing, to be fixed to a foundation in c.a. in which bars were preceded for the anchoring of the plate.

what size would you make holes on the plate?
1) hole diameter = fixing bar size + 1 or 2 mm tolerance
2) hole diameter = fixing bar size + 5 or 10 mm to make it possible to compensate for any bar laying tolerances?

Thank you.

 

[MassiVonWeizen]

for some customers it is used to make the hole plentiful (for example for a m30 the hole is ø46, then puts a washer with hole according to norm, in this case ø33, to bet and weld in operation.
always that it is possible to make welding in the yard.

 

[gil]

Does welding serve for horizontal spins?
if I tighten the plate with washer and bolt on both sides, is the friction force not enough?

 

[Alberto.E]

Usually add 2 mm to the bolt size is made for steel/steel connections. with concrete things change because accuracy is definitely not the same. In Australian standards as well as Americans it is suggested to add 1/4 of the hole diameter that you would normally use.
For example:

bar 30 mm
standard hole = ø32 mm
hole to perform = 32 + 1/4 of 32 = ø40 mm
Of course, as he said, we must apply the washer.

I hope you can help.

 

[MassiVonWeizen]

welding serves to recreate the situation of a hole with a couple of millimeters of play on the foundation plate.
for the friction force I cannot answer you; definitely depends on the situation of use of the anchor.
specific that I do not make foundations or related calculations, I develop only basic projects.
This is a solution that some customers, in the steel industry, are usually adopting.
instead in the case of a rather large structure, 15x20 meters, with beams distant a few meters, I know that a system of blades was used that recalculated the foundation plates and that were connected between them. this has allowed to faithfully recreate the ground fixing position of the structure.
if I can try to put an example of the fixing through welded washer, just to understand better

 

[Alberto.E]

I'm sorry to say something.
actually add 6 mm to the diameter of the bar for the lower and equal dimensions
m24.
add 8 mm for bars of size greater than m24.
therefore in the previous example for bars from ø30 the hole must be 38 mm.

 

[gil]

alberto.e, would you please give me a reference to the legislation you refer to? A match like this would be important.
Thank you.

 

[MassiVonWeizen]

I personally don't know if you refer to precise regulations, the data I have come from the customer's internal regulations, but since the values are all similar I imagine. You could search among foundation dye manufacturers if they have documentation.
I'll put you a typical one

 

[gil]

thanks Massivonweizen
In practice, I go to apply more forometrics similar to those indicated in your computer. In my case, these are prescriptions, but I don't know if they have a regulatory response, or it's just common sense.

In the first case, in case of customer objections, I could provide the legislation that is indisputable, in the second case the common sense is not easy to transmit.

 

[radio]

... but I don't know if they have a regulatory match, or it's just common sense.

In the first case, in case of customer objections, I could provide the legislation that is indisputable, in the second case the common sense is not easy to transmit.

the standard for screw holes is the uni en 20273, qui (table1) find the drilling diams for each screw diam.

Bye.

 

[MassiVonWeizen]

I believe that gil refers to a standard for drilling increased on foundation plates, such as what said tree-lined:

add 6 mm to the diameter of the bar for the lower and equal dimensions
m24.
add 8 mm for bars of size greater than m24.

 

[radio]

I believe that gil refers to a standard for drilling increased on foundation plates, such as what said tree-lined:

I do not know if there is such a specific norm and, since distribution plates are used, welded or not, to be interposed between the foundation plate and the nut, perhaps it does not even serve.

Bye.

 

[gil]

I refer to the specific case of foundation plates.

seal non-servable easyno

I thought so too, then in a discussion I found it impossible to explain that, without adequate increase if the masons pose the dime with a error greater than 0.5mm the columns will not be aligned and perhaps they will not even stick in the ladies.

seems incredible, but there are those who do not believe that a building of 20 - 40 merters has a margin of dimensional tolerance.

Indi for which I seek a specific norm or prescription.

 

[Sorridi]

tolerances on the holes of the plates are those indicated by radio.
and this applies to both joint plates and foundation plates.
how to put backgrounds in exact position is burden and responsibility of the performer.
when you make metal structures you leave the building tolerances and enter the field of mechanics. therefore respect those.

you make blades with the wallpapers already threaded inside, you drop them in exact position, you lock them before the jet controlling the position (also by means of small welds to the armor bars) and then you throw.
the dime will be paraded at the aging of the jet.

on the other hand there are other reasons to do this.

Imagine placing a column from 8 meters he400b on m26 wallpapers. the posi (with the crane you can not put it by hand), goes in position with an error of more or less 6mm. after I put the beam of the first scaffold and (magic) you find the shortest (or longer) of 6+6mm?
What are you doing? Do you copy the joint plate? Do you put on a compensation thickness? Move the column a bit?

other consideration is the type of bond.
with a tight tolerance like that of the norm, the joint basically acts as an incarceration. If tolerance is so much, the joint would behave like a cart. and this changes all calculation patterns.
it is not possible to replace the seal of a passing hole in a homogeneous foundation plate (typically thicknesses above 10mm) imagining to put a washer on it.
What thickness of the washer? and welded with what criteria?

I'll put a print on the prescriptions that I give in the process, so you can solve the problem with the type, gil.

 

[gil]

Thanks smiles
the problems listed I solve them in this way
1) the transverses are anchored to the pillars by means of asolate dishes that allow a minimum tolerance

2) Washers are of the same thickness of the plate one above and one under narrow with bolts in such a way as to create an friction. also welding the washers to the plate

However I understand the reasons you have expressed.

 

[Sorridi]

the problems listed I solve them in this way
1) the transverses are anchored to the pillars by means of asolate dishes that allow a minimum tolerance

So you're making them all with saddles?
only the saddle allows you to move without loss of support (in practice a cart). If you want an ink, you have to go of junction plates and irrigation plates in the column, but you lose the tolerance you want.

2) Washers are of the same thickness of the plate one above and one under narrow with bolts in such a way as to create an friction. also welding the washers to the plate

the washer (admitted and not allowed) you can put it on one side.
that in the jet (bottom part) you can't put it and above all you can't tighten it so much to create friction. You won't get to the bolt so you can't lock it. If you miss the vertical portion of the bolt that holds it (and no one tells you that you don't turn during the jet) you find that the washer blocks you the plate out of quota (if too high) or that does not create friction (if too low).
The lower one can never weld it. you will have the jet on one side and on the other the foundation plate.
Welding a sp.10mm washer on a 10mm plate means making a 10mm groove height welding in operation. Do you know what local stress at steel? especially for the holes close to the edges badly lower the resistance to rewinding of the plate.
It's true that the local thickness doubles, but it's also true that it "cuoci" steel.

But at this point, isn't it better than a counterplate with welded wallpapers in the workshop? put all the plate with the backgrounds and, after laying, maybe the column moves 6mm, but fits perfectly in its place with tolerance below the mm?

 

[radio]

I refer to the specific case of foundation plates.


I thought so too, then in a discussion I found it impossible to explain that, without adequate increase if the masons pose the dime with a error greater than 0.5mm the columns will not be aligned and perhaps they will not even stick in the ladies.

seems incredible, but there are those who do not believe that a building of 20 - 40 merters has a margin of dimensional tolerance.

Indi for which I seek a specific norm or prescription.

in some cases of machine bases to be fixed on the ground by means of rods (tirafondi?), we have provided dimes/combatements with narrow tolerance holes for the positioning of the rods to drown in the concrete.
in this way the fixing holes of the base, to a greater tolerance than those of the dime / counterplate, were in correspondence of the rods; In our case, however, the size (max 2x2 meters) allowed to do so in your not know, but it seems to me that you smile is more or less of the same notice.

Thanks smiles
the problems listed I solve them in this way
1) the transverses are anchored to the pillars by means of asolate dishes that allow a minimum tolerance

2) Washers are of the same thickness of the plate one above and one under narrow with bolts in such a way as to create an friction. also welding the washers to the plate

However I understand the reasons you have expressed.

in case you are forced to deal with positions/interaxes of the tie rods with tolerances so wide, to be used "washers" to be interposed between plate with hole/asola "large" and nut, the problem is no longer the correct coupling screw/hole (the "shocket" can have holes of unequal diameter) but the bending/cut check(?) of the "shocket".
you find yourself with a plate (with the thicknesses in play is still considerable slab?) perforated loaded at the center by the bolt, and rested on the edges of the hole/asola of the plate below to check taking into account the size of the hole below, of the constraints (is welded or not), of the thickness of the "wax", of the material and of the load.
then in practice certainly the size of the "washers" you use are more than enough to you, but if you are asked for a verification?
as an example I attach a pantry found on the net, see in particular "anulary plate"; probably exists and it is accepted/acceptable a simplified calculation scheme, let's see if someone who reads us knows and proposes it.

Bye.

 

[gil]

Okay.
thanks for the availability.

 

[gfrank]

Hi.
As a result of a lively discussion I would like to ask you this question.
take for example a metal frame with base plate as from drawing, to be fixed to a foundation in c.a. in which bars were preceded for the anchoring of the plate.

what size would you make holes on the plate?
1) hole diameter = fixing bar size + 1 or 2 mm tolerance
2) hole diameter = fixing bar size + 5 or 10 mm to make it possible to compensate for any bar laying tolerances?

Thank you.

As a rule the fixing bars are laid in operation by means of the use of a blade. the positioning of the blades, is carried out accurately, according to the "importance" of the structure. For example, in the realization of thermoelectric plants, control of the blades: Alignment, altitude, rotation, is effected with precision tools, which ensure for subsequent laying of structures, a tolerance of very few millimeters.
the base plate, as mentioned above, does not require special holes in size, as the tolerances are resolved to 99% with the laying of the bars by means of the blade.