Flange to web welds calculation of WWF
Flange to web welds calculation of WWF
(OP)
If the flange to web welds is not develop the full capacity of web. How to check the weld strength?
Let say, web=30mm, bending f=0.6Fy, shear ft=0.2Fy, how to calculated the weld thickness?
Let say, web=30mm, bending f=0.6Fy, shear ft=0.2Fy, how to calculated the weld thickness?






RE: Flange to web welds calculation of WWF
q = VQ/I
RE: Flange to web welds calculation of WWF
Some time I'm not confident to the result. I had a gider with 26mm web. Full strength weld thickness =26/.7/2=19mm(2 sides), shear capacity design only need 10mm thickness (2 sides). The weld strength is only 54% strength of web.
RE: Flange to web welds calculation of WWF
Back to Mechanics of Materials. Pure bending:
q=dM/dx=0
Not connection need?
RE: Flange to web welds calculation of WWF
RE: Flange to web welds calculation of WWF
burtonSTR, the flange to web weld requirements om beams are usually smaller than web thickness. Normally shear differencial is gradual (except at supports).
In many cases I have seen the weld size being determined by the minimum weld size requirements rather than capacity.
RE: Flange to web welds calculation of WWF
RE: Flange to web welds calculation of WWF
RE: Flange to web welds calculation of WWF
We consider pure bending, the idealistic situation. If not connection, how can the flanges and web work together? Bending for 3 plates separately or "W" shape is total different
RE: Flange to web welds calculation of WWF
Given that, design your weld for those conditions. Don't forget to combine the conditions for a compatibility check.
RE: Flange to web welds calculation of WWF
Thank every.
To JrStructural Eng
V=9000kN, Web=3000mmX20mm, weld:E49XX
q=V/h=3kN/mm
Required fillet welds thickness
D=3/0.156=19.2mm
used 2x10mm fillet welds
RE: Flange to web welds calculation of WWF
what is Q? I am trying to remember this stuff, havn't done shear flow since 2nd year uni
V is the total load over the entire section right?
RE: Flange to web welds calculation of WWF
RE: Flange to web welds calculation of WWF
I am missing something...monday morning I guess...
he went q=V/h? I can't remember what 'Q' is, but I am guessing this must mean Q/I = h?
RE: Flange to web welds calculation of WWF
RE: Flange to web welds calculation of WWF
Dik
RE: Flange to web welds calculation of WWF
Here is theoretical situation. I tried to insert realistic loading. How would you set up the calcs for a situation like this where the steel angle is providing lateral bracing to the concrete wall.
In order to find the shear flow through the conc. anchors you would use the max shear at base correct? Perhaps you/someone experienced could attach a pdf laying this problem out. In a loading case like this, i'm not sure how you would size a steel angle, or the anchors but I have always wondered! Thanks for your help in advance!!
RE: Flange to web welds calculation of WWF
I don't know that I would say the angle is bracing the wall. It looks more like using the angle to strengthen a structurally deficient wall (i.e. attempting to add to the tension steel. I would do a typical reinforced concrete (or masonry) design and size the angle that way.
RE: Flange to web welds calculation of WWF
Dik
RE: Flange to web welds calculation of WWF
I used the cracking Moment of Inertia or should i have used the gross moment of inertia, which would give me less shearing force.
RE: Flange to web welds calculation of WWF
RE: Flange to web welds calculation of WWF
RE: Flange to web welds calculation of WWF
RE: Flange to web welds calculation of WWF
1. Size the angle assuming it is reinforcement for the wall.
2. Arbitrarily select some spacing that makes sense (maybe 18").
3. Determine the tension in the angle (at factored load levels) just below each anchor (starting with the second anchor).
4. Use the tension force just below the second anchor to size the first anchor.
5. Use the differential tension force just below the third anchor to size the second anchor.
6. Continue this procedure until you get to the max moment location.
7. Use the largest anchor at all locations.
I just made a quick spreadsheet and this does seem to work out. I was actually questioning myself because I started thinking that the anchor size would actually increase as you get closer to the max moment (that the max shear for the anchors would be at the max moment location), but that's not true. The parabolic shape of the moment diagram (i.e. the x2 term if you develop the equation) helps the diagram shoot up quickly then level off. The max shear in the anchors is still at the first anchor, so I convinced myself that it's completely appropriate (probably more so than trying to use the shear flow formula for this instance).
You can probably quit at step 4 since the first anchor will be the controlling one.
Here is an alternative:
1. Same as above.
2. Choose what size anchor you want to use and determine the shear capacity.
3. Use the formula M/jd (where M is the moment in K-in, and jd is the distance from the centroid of the compression block to the reinforcing - the angle) starting at the bottom of the wall. Set M/jd=<the shear capacity determined in step 2.
4. Determine the location where the inequality in step 3 is true and use that spacing everywhere.
Both of these will get you out of having to figure out which I to use for the wall.
RE: Flange to web welds calculation of WWF
Calculate the force in the flat according to your moment diagram. Finally, provide enough anchors to develop that force. above and below the point of maximum moment.
Best regards,
BA
RE: Flange to web welds calculation of WWF
A couple questions:
wouldn't you still get similar values by shear flow calc? In essense, it relates the shear to the tension in the section adjacent to the cut? (Doesn't it?) Just curious if you checked your answers against shear flow computation to see if they are close.
At a 48" angle spacing, out of curiosity, what governing anchor 'shear' did you get given your approach? (If you don't mind me asking). My values were pretty high from the shear flow calculation.
RE: Flange to web welds calculation of WWF
Wf = 45 kN/m
L = 3.0 m
Mf = 0.1283*Wf*L = 17.3 kN-m per m
Tf = Mf/d = 17.3/0.15 = 115 kN per meter
The angle (or strap) has to take a maximum factored tension of 115 kN/m. The anchors must develop that force each side of the maximum bending moment. The spacing must develop the simple span bending moment at all points.
Best regards,
BA