Yield Line Analysis 6

[dik]

Does anyone have a paper reference or calculation for the yield line solution to a tab welded to an HSS. I have one somewhere, but cannot locate it.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[dauwerda]

Not sure if you have access to the AISC Steel Construction Manual, but the 15th edition addresses this on pages 9-14 through 9-16.

This is also the chord wall plastification check given in table K3.2 of AISC 360-10 (Equation K3-6) which is available for free from AISC's website.

 

[WARose]

At this point, I typically compare that force (on a kip/inch basis) to the allowable as per Chapter K in AISC. (I.e. the allowable force in a longitudinal plate going into a wall of a HSS. See Table C-K1.1(a) on p 16.1-368 in the 13th edition.)

But since you asked for a yield line equation.....

The 'Handbook of Structural Steel Connection Design and Details' (by: Tamboli, 1999, p.152-153) presents a yield line solution for a seated connection to the web of a column via a clip angle (i.e. the web strength from the eccentric loading). I would assume this would be applicable for your case.

 

[DrZoidberWoop]

see "Single Plate Connections to HSS" on pg. 10-153 in the 15th edition of the manual for AISC's latest stance on the scenario.

This thread has a link to the latest AISC article on axial loads framing to HSS walls. A full explanation of the topic, with examples and calc derivation, is provided on pg 17-19 of the link.

https://www.eng-tips.com/viewthread.cfm?qid=458342

 

[dik]

dauwerda: I have access to the 14th edition and cannot find a reference. I'll try to download the info...

WARose: I"ll see if I can dig up the info...

thanks...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[dik]

DZW... that was the document I couldn't find.... thanks very much.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[WARose]

Just a FYI: the AISC article DZW links to (in the other thread)....that yield line equation they give is very similar to the one in the book I cited (by Tamboli).

 

[wrxsti]

aisc design examples v15.1 has example K.6
link below

https://www.aisc.org/globalassets/a...ds/first-semester-design-examples---v15.1.pdf

which checks for hss wall slenderness and punching shear at the face (no more table K1.2)

chord plastification, i believe is under axial loads
which are indeed determined by yield line
see link below

https://steeltubeinstitute.org/resources/transverse-plate-to-squarerectangular-hss-connections/

However, the code says punching shear is the limit state and not wall plastification

if you check same K.6 for design examples v14.1

it goes into some more checks from table K1.2

which include maximum plate thickness

 

[dik]

Thanks... I've got my son trying to chase down the text.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[dik]

The examples only go to J. I'll go over the STI paper... Thanks

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[evo10]

interesting aisc says punching shear
but chord stress interaction parameter could drastically decrease chord plastification

 

[evo10]

here is a link with K

https://www.aisc.org/globalassets/aisc/manual/v15.1-companion/v15.1_vol-1_design-examples.pdf

 

[dik]

Example K.6 appears to address this... thanks very much. I think the problem's solved... I'll drop an SMath program when I get it written.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[dik]

Example K.6 Thanks

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[evo10]

also here
the one on STI is generic for branched rhs truss

this example should give idea of calculating Qf

 

[evo10]

also this

 

[wrxsti]

The Hp^2 in the punching shear calculation seems to always have a higher value

than

the chord wall plastification Mn above which has t^2

 

[dik]

Thanks...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[wrxsti]

i am not sure which approach to take AISC 15 indeed says its not required to check for
shear yielding(plastification) and only to check for punching shear
but i tried using the flexural strength for connection formula ( chord plastification) even though it says not applicable for β < 0.25
but it also says that for axial branch table K2.2 and they use the same equation for longitudinal plates

anyways for this example im getting higher ratios for chord plastification than punching

see sample calc below


Connection Loading:

Beam end Reaction (Shear), R = 11 kips

Member Properties:

Tab Yield Stress, Fyp = 36 ksi
Beam Tab Height, Hp = 8 in.
Tab Thickness, tp = 0.25 in.
Distance to row of bolts, D2 = 3 in.
Girder/column web thickness, twg = 0.25 in.
Girder/column width, B = 8 in.
weld thickness = 0.25 in.


Fyg - column/girder yield stress = 46 ksi
Fug- column/girder ultimate stress = 58 ksi
E = 29000 ksi

The available strength of the face of the HSS for the limit state of punching shear

Ω = 2
Ra * e = 33 kip-in.
Fu*t*lp^2/5= 93 kip-in.

Check Ra * e <= 1/Ω*Fu*t*Hp^2/5 AISC Manual Eq. 10-7a

Result Ra*e/(1/Ω*Fu*t*lp^2/5) 0.333333 < 1, O.K.


Connection available flexural strength table K3.2 chord plastification

lb = 8.00 in. lb = Hb/sinθ
η = 1.0 η = lb/B
β = 0.03125 β = Bb/B


did not use U and using Qf as 1 for this example (Qf really below 1 if using U so Mn even less)

Qf = 1 Qf = sqrt(1-U^2) Eqn K1-17

Mn = 54.65 kip-in. Mn = (1/1.5)*(Fy * t^2*Hb) * [ (1/(2* η)) + 2/sqrt(1-β) + (η/(1-β)) ]*Qf Eqn K3-6

Result Ra*e/Mn = 0.54839 < 1, O.K.

 

[dik]

I disagree... because there is a significant moment on the face of the HSS, plastification of the face and a yield line pattern will develop. Which AISC publication did you use for the example? Thanks...


Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik