Tubular moment connection 1

[haynewp]

Are there any references available on using welded moment connections with a TS beam to TS column to create a bent as part of a rigid frame? Also, client wants to use a bent TS2x2x14GA to create the ridge of the frame (how in the world do I analyze that?). These will be used to support little carport and mini-storage buildings.

 

[LPPE]

You must be careful in welding gage sheet metal, because it is easy to burn completely through. 14 gage is just over a 1/16 thick, and the smallest HSS2x2 you can get is 3/16 thick. I would recommend looking through AISC and AWS to see what maximum weld size you could possibly use on a 14 gage, and see if you can get the capacity your looking for with that size weld. You are looking to weld this bent, correct? If not, forget this post!

 

[haynewp]

Yes, I am looking to weld (complete penetration) this bent, one tube directly to the other on an angle (angle depending on roof slope). What about local buckling effects? I'm having a hard time finding research or reference on this type of moment connection.

 

I think you can treat this as a box type girder (beam) and design according to AISC Appendix B. You need to calculate Qa, Qs and Q to correct the gross area of your TS section. Physically, it leaves 4 corners as the effective area since your b/t or d/t are beyond compact or non-compact region.

The remaining question is how you transfer the moment from the beam to column. What you have to do is to place a diaphram plate in the column to back up the bottom flange of the beam.

 

[austim]

Try to see if you can get your hands on a copy of "Design Guide For Rectangular Hollow Section (RHS) Joints Under Predominantly Static Loading" authored by J.A.Packer, J.Wardenier, Y. Kurobane, D.Dutta, N.Yeomans, edited by CIDECT (Comite International pour le Developpement et l'Etude de la Construction Tubulaire), and published by Verlag TUV Rheinland. ISBN 3-8249-0089-0.

[I apologise for being unable to put the various acute accents and umlauts where they should be ].

This is a pretty useful guide, written in English (despite its continental European origin).

 

[austim]

Hi again, haynewp.

I probably should have added that if you have any problem in locating the CIDECT guide, you can get it (by a very roundabout way) from the bookshop of the Australian Institute of Steel Construction.

http://www.aisc.com.au.

'Our' AISC also has seven other CIDECT guides for sale, including circular section joints, structural stability of hollow sections, design for fire, concrete filled hollow columns, mechanical applications, welded joints under fatigue. Prices range from A$27.50 to A$66.00 (for the welded joints under fatigue loading guide), plus P&P.

With the A$ currently ranking at about A$2 = US$1, the costs should not be too frightening.

 

[rday]

Haynewp,

The US AISC publishes a Hollow Structural Section Connections Manual using the LRFD methodology.

http://www.aisc.org

Rik D

 

[butelja]

I believe that AWS D1.1 Structural Welding Code - Steel has a section on tubular members that covers this.

 

[jamie2000]

There is an article in Modern Steel Construction magazine (November 2001, published by the American Institute of Steel Construction) about designing HSS connections. This article referred a publication called "Hollow Structural Sections Connections and Trusses - A Design Guide", by JA Packer and JE Henderson as the primary reference for design information on HSS connections. The publication is published through the Canadian Institute of Steel Construction.

Jamie