topic Re: Truss node connection design with an angle less than 30 degrees in Robot Structural Analysis Forum

Truss node connection design with an angle less than 30 degrees

Jummybear — Tue, 11 Nov 2014 13:56:50 GMT

In connection verification results I can read Robot remarks that "Diagonal angle is too small. 29.5 [Deg] < 30.0 [Deg]". I have a question about connection (weld) capacity with an angles less than 30 degrees. How robot calculate weld length in this way? In many cases its recommended not take into account weld from the acute angle.

Re: Truss node connection design with an angle less than 30 degrees

Artur.Kosakowski — Wed, 12 Nov 2014 12:18:12 GMT

In the same way as for 30 deg but with this additional warning.

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Re: Truss node connection design with an angle less than 30 degrees

Jummybear — Fri, 05 Dec 2014 10:30:00 GMT

Is it possible to exclude from calculation welds which are locatud in acute angle? Its recommended in many books because such welding is hard to perform well. I think that robot should give the results of calculating with maximum margin of safety.

Re: Truss node connection design with an angle less than 30 degrees

Artur.Kosakowski — Thu, 18 Dec 2014 15:19:55 GMT

No, currently this cannot be set. Would it be possible for you to send me a references to the books you mentioned please? Thank you.

Re: Truss node connection design with an angle less than 30 degrees

Artur.Kosakowski — Wed, 24 Dec 2014 12:02:55 GMT

I hven't been able to find the reference where it is said taht such welds are recommended to be not considered but I have managed to find something that says the welders should be qualified to make such welds instead

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&cad=rja&uact=8&ved=0CCoQFjAC&url=https%3A%2F%2Fwww.aisc.org%2Fbookstore%2FitemRedirector.aspx%3Fid%3D15130&ei=lqmaVIm4NsW-PanUgYAM&usg=AFQjCNGIMQLxDk-JAM1AWZiyv-SNPi6B4Q&bvm=bv.82001339,d.ZWU

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Re: Truss node connection design with an angle less than 30 degrees

Jummybear — Wed, 07 Jan 2015 14:27:49 GMT

Sorry for not answering, was on christmas vocation.

I partially agree with you. Its hard to find stright clause that it should not to be considered in calculaton. Mostly its discussed in engineering forums and many of engineers prefer not to take such welds into account. I also hold this point of view. Another reason (first one is weld quality in acute angles) is that such weld are not effective with angles less than 30 degrees. I can understand if i have 28-29 degree more or less its ok but smaller numbers raise some doubts.

Probably in countries with good boulding culture (germany, norway etc) its ok but in our "conditions" its better choice to exclude such welds from calculation and sleep well 🙂 In my case I left connection design ratio about 0,5 and not more. And yet i think such possibility (exlude acute angle welds from calculation in Robit) would be great.

One more link related to the topic:

http://steeltubeinstitute.org/hss/faq/faq-of-the-week-week-4-3/

Re: Truss node connection design with an angle less than 30 degrees

Artur.Kosakowski — Thu, 08 Jan 2015 08:06:41 GMT

One more link related to the topic:

http://steeltubeinstitute.org/hss/faq/faq-of-the-week-week-4-3/

Smaller angles may be acceptable, although not pre-qualified, if you can confirm with the fabricator that proper structural quality welds can be achieved.

This seems to be similar to the one I found. My understanding is that in both cases the "answer" is that you should make sure a fabricator is capable of making a "proper" weld rather than negect welds in calculations of a connection capacity.

What is the reference to the screen capture you posted?

Re: Truss node connection design with an angle less than 30 degrees

Jummybear — Thu, 15 Jan 2015 13:49:54 GMT

I cant post whole document couse its too big (13.5mb)

But the name of it is International Conference on Tubular Structures, May 9-10. 1996, Vancouver, British Columbia.

http://www.scribd.com/doc/31192668/International-Conference-in-Tubular-Structures-1996#scribd

Re: Truss node connection design with an angle less than 30 degrees

Artur.Kosakowski — Thu, 15 Jan 2015 15:13:24 GMT

Thank you. I have added your request to the wish list with the reference to the materials you provided.

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