Flare Bevel Groove Weld Reinforcement

By bswanson Date 12-18-2003 18:49

Hello, New to Forum.

In following a design example in AISC's Hollow Structural Sections Connection Manual, I have come across a passage that refers to criteria for reinforcing a flare bevel groove weld with a fillet weld. The example problem (Ex. 5.4, page 5-22) addresses the weld of a WT section to an HSS Column. The passage,..."Note that if the weld [flare bevel] is reinforced with a fillet weld, the effective throat could be increased by 0.25 times the wall thickness per AWSD1.1 which would increase the weld strength by 40 percent"....seems to imply a limit to the reinforcement of a flare bevel for the HSS Section more restrictive than simply building up the effective throat thickness to the HSS shear and/or tension rupture strength.

I have combed through the AWS D1.1:2002 to the best of my ability over the last couple of days and have found nothing specifically regarding this issue with flare bevel groove welds. With deadlines approaching, well,...you've all been there.

Can anyone cite the AWS code section that addresses this topic? Or, does anyone have knowledge they might share with the effective strength limits of fillet reinforced flare bevel welds?

Any assistance in this matter would be greatly appreciated.

Thanks in advance,
William P. Swanson, P.E.

By DGXL

Date 12-18-2003 22:12

If your detail conforms to the BTC-P10-GF joint designation (for the GMAW/FCAW processes), then note 7 on page 72 would apply to your connection. This note pertains to fillet weld reinforcement of flare-bevel groove welds.

Not sure if this is the specific info your seeking.

By bswanson Date 12-18-2003 23:59

Thank you for your response and direction to the note (Note 7, pg. 72). The welding process is SMAW and the Joint Designation is BTC-P10 and this note still applies.

"7. If fillet welds are use...to reinforce...groove welds in corner and T-joints, these shall be equal to T1/4, but need not exceed 3/8 in."

I still have an unresolved issue with this note, in that it specifically states a size of fillet reinforcement of T1/4. I know what T1 is, and I understand as T1/4 exceeds 3/8", the fillet reinforcement need not.

However, I need more build out than T1/4 to reach my effective width size for my desired weld strength. Am I restricted to T1/4? This note does not state T1/4 as a max or min., rather as 'shall be equal to'.

So, if I were to build up a flare bevel weld on a 1/4"(.233") wall rectangular tube with a 1/4" fillet and use the shortest distance from the face of build up back to the start of the flare bevel to measure my effective width, and then use this width to calculate my weld strength-it sounds like I would be at variance with the code. (Obviously a 1/4" build out is greater than .233/4.=.05825)

If I were to need more weld strength for this joint and one that is still pre-qualified weld, is my only solution thickening the tube wall? Thus flare bevel weld size and fillet reinforcement size is larger. Or can I build out the fillet reinforcement greater than T1/4 and calculate the effective width?...........Which personally is what I would, of course, prefer.

Anyone up to further enlightening this greenhorn?

By DGXL

Date 12-19-2003 00:31

William:
If you are the RDP, you do have the authority to waive the prequalifed joint specifications as noted in 1.4.1 of the General Requirements. The prequalified WPS requirements may be modified by the RDP or by qualification in accordance with Section 4 of the code.

Note 7: "...need not exceed 3/8"..." is not a mandatory code provision. If the word shall is used, then it becomes a code requirement (1.3.6 in it's entirety). I get many projects that do not conform with the D1.1 requirements, the RDP then modifies the code provision or testing of a particular joint.

By bswanson Date 12-19-2003 23:01

Thanks again for your response. I'm getting responses through other forums that are leading me to believe that the T1/4 requirement is the default dimension for a contouring fillet to reduce stress concentrations at the flare-bevel groove weld T-Joint or Corner-Joint.

Providing my interpretation is correct,...If I want reinforcement beyond what a T1/4 fillet provides, then for 'weld strength' I am guided by provision 2.3.2.7, the Flare-Bevel-Groove-Weld Figure 3.3 itself, and the Effective Throat diagrams in Annex I of the Code. Which has been the method I've been using to calculate the weld strength. The diagrams would be slightly modified to show a flare bevel width of 5/8T1.
Sound good? I hope so. I will follow up with respect to addtional informaiton I receive or find.

Thank you once more for your time.