Use European standard in switzerland

About the development of the FEM module/workbench.

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thschrader
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Use European standard in switzerland

Postby thschrader » Tue Jul 24, 2018 10:08 am

@bernd off topic:
We have a new project in Switzerland (construction of a antenna-mast at +2000 m for swisscom).
Can I use Eurocodes for static calculation? Or must I use SIA-codes?
Thomas
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bernd
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Re: Use European standard in switzerland

Postby bernd » Wed Jul 25, 2018 4:08 am

no longer offopic.

AFAIK european standard is valid in switzerland too. Some remarks:

- AFAIK european standard misses loads for switzerland, means you may need SIA 260 and SIA 261 for loads
- There is a documentation in Switzerland for wind on masts see http://shop.sia.ch/dokumentationen/inge ... /D/Product there might be another one especially for masts ...
- I did some masts in 3000 m 15 years ago. I remember some special formula because density of air is much less as higher the mast is. As less density as less pressure for the same wind speed.

we may get in contact directly thomas.


Ahh normaly in switzerland there is no Prüfingenieur at all. You even do not need to give you structural calculations (Statik) to someone else. You just hand out your drawings.

bernd
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Re: Use European standard in switzerland

Postby thschrader » Wed Jul 25, 2018 1:14 pm

Hi Bernd,
thanks for the info.

No controlling-engineer (Prüfingenieur) in CH:
Thats interesting, I didnt knew that.
But we must deliver our stuff to the local government for checking (Baueingabeplan).

Air density:
Thats a good point, thanks for this. I found a reduction formula
in a swiss chimney-calculation. At +2000 m the density (and the windforce)
reduces by 20%. Thats good.

In the last two days we have got tons of documents from Swisscom
(SIA/Eurocode/design-manuals...)
At the moment I discuss with my colleagues about statics.

We have three problems.
First:
Site location is in Adelboden-Sillerenbühl at the top of a mountain (in german: Kammlage).
The formula for calculating the effective static pressure is
qK=cd*cf*qp0
SIA gives
qp0=3,30 kN/m^2 at +2000 m (more then 330 km/h wind-speed)
cf: factor >1 for topographie
cd: factor > 1 for turbulence
For calculating the turbulence factor cd, SIA261 points to SIA-DO188, when using
the formulas I get a turbulence factor of 2,6, which is far to high. Antenna systems
have a very high stiffness (eigenfrequency approx 1,7 Hz, otherwise the link of
the radio mirrors would break due to much deflection). The cd should be approx 1,2.

Second:
In germany we must calculate two different load combinations:
self-weight+100% wind-load
self-weight+100% ice-load + 60% wind-load on changed geometry (due to ice)
I have no idea how to get icing-parameters of structures on mountains.

Third:
As far as I have understood the SIA, a earthquke-calculation is mandatory in switzerland.
Is that right? The antenna-mast has only a height of 16 m, this is not a skyscraper...

And our CAD-technicians have a problem. Swisscom wants 3D-views of some steel parts.
But they have done only 2D-drawings on autocad the last years. Oooops...

So far so good.
BTW: Sillerenbühl is a nice place
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bernd
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Re: Use European standard in switzerland

Postby bernd » Wed Jul 25, 2018 4:00 pm

I have lived near taht place for 5 years. Have a look at Zweisimmen! Its a great place for skiing and mountain walking! :D

Yeah no proof engineer, only for nuclear power plants, maountain cable cars, huge bridges and tunnels and such really important stuff.

Baueingabeplan is just drawings, no structural calculations at all. Earthquake should not be a problem. You are on rock ground. But you never know ... You could rake 20% of the vertical quasi ständige load as a horicontal load in center of mass to get a feeling what happens at earth quake. I woud not be surprised if wind is much highter. 330 km/h is huge!!! Is it really that much.

As stated we may get in touch directly.


cheers bernd
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HarryvL
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Re: Use European standard in switzerland

Postby HarryvL » Wed Jul 25, 2018 5:19 pm

bernd wrote:
Wed Jul 25, 2018 4:00 pm
I have lived near taht place for 5 years. Have a look at Zweisimmen! Its a great place for skiing and mountain walking! :D
Ok, ok, ok. Do realize that some of us come from a country where the highest mountain is 322m. No reductions for air density. No winter skying. Just FreeCAD to get us through winter. :ugeek:
thschrader
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Re: Use European standard in switzerland

Postby thschrader » Wed Jul 25, 2018 8:35 pm

HarryvL wrote:
Wed Jul 25, 2018 5:19 pm
Just FreeCAD to get us through winter. :ugeek:
Yes Sir, but with poelser :)
Denmark is a beautiful country. My first visit was when I was 6 years old.
Long time ago, but I still remeber...
danske_poelser.JPG
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bernd
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Re: Use European standard in switzerland

Postby bernd » Thu Jul 26, 2018 4:57 am

How about iceskating? Ahh and AFAIK because of liberty laws there are other cool smokes in the air instead of density reduction. Hey and FreeCAD is one of the greatest things to spend time with.
thschrader
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Re: Use European standard in switzerland

Postby thschrader » Fri Jul 27, 2018 4:20 pm

FC made my day...
The green/red polygon are measuring-points of topography by the geotechnicians.
The foundation is a standard-part.
The foto is an optical-fake, we have to remove much more rock as expected.
(But how: explosives?)

@Bernd:
Earthquake is a minor load-case, no problem. According to SIA261 I calculated the
max ground acceleration by using the correct response-spectrum. Only 0,4 m/s^2
acceleration, thats nothing for the mast.
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josheeg
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Re: Use European standard in switzerland

Postby josheeg » Fri Jul 27, 2018 5:02 pm

Wow impressive use of freecad!

Here is one of the specifications page of dragon plate carbon fiber tubes It does not show units that would go into freecad fem please help
dpspecs.png
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Last edited by josheeg on Fri Jul 27, 2018 5:12 pm, edited 1 time in total.
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HarryvL
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Re: Use European standard in switzerland

Postby HarryvL » Fri Jul 27, 2018 5:11 pm

thschrader wrote:
Fri Jul 27, 2018 4:20 pm
... we have to remove much more rock as expected.
(But how: explosives?)
Why not anchor in the rock rather than removing it Thomas?