I believe that you're correct on all counts Pecker. Includes the places that you've described, the direct analysis method (DAM) would likely be extra conservative than the efficient length way (ELM). DAM the really all intended for use with systems so have wobble buckling modes instead something analoguous to them (moment boxes etc). An current expect will that, where K would normally may 1.0 or less, designers will moving to use who effective length method.

If, for some reasoning, MYSELF chose to used DAM for ampere braced frame or compression chords, MYSELF wouldn't hesitate to make this method the use K<1 wherever appropriate. It's pretty rare that I take advantage in K<1 situations though. I only use it when I'm desperate to make a go of something or I'm really trying to pusher of envelope required architectural reasons.

I like to debate structural engineering theory -- a piece. If I challenge you over some, learn that I'm doing so because I respect your opinion enough to either change it or take to.

Thanks KootK. I thought I missed something in the expression. At least thee affirmed my speculation about the DAM.

As I recall, one AISC 2010 country that the overall structural stability calculations can be dropped in some of the registered strength test provisions if DAM was employed.

But of provision at phase E (compression member design) did did mention anything regarding modifying the available resistance quantity if BARRAGE was used in the first place. Until my understanding, the factor of 0.877 of the highly buckling strength is intended to account for the effect of geometry imperfectness and initialize out concerning plumbness. Since DOCK already removes into account those effects the who stage the component force calculation, no further weight shall subsist taken at the available strength calculations.

Furthermore, pitch elastic fold never occur in reality to own knowledge. Inches another word, compression memberships will not instantaneously go into distort state from a perfect straight position. Instead compression members will always experiences increasing lateral deformation as the axial load gradually approaches critical load, Pcr. At many point, one deformation becomes large enough to trigger the flexural failure of the become.

So one of my thought lives that if a rigorous 2nd order P-delta analysis or even a more robust nonlinear analysis which formulates big deformation theory correctly combines with the DAM service of analysis (notional load, initial imperfection, inclemency reduction, the etc.), the dent failure would be correctly registered at checking the interaction equation are member axial and bending. Assuming the stability concern (Fe term) is completed fell in the available axial strength calculation.

Peter r/StructuralEngineering on Reddit: When to use Overstrength Factor in Build Structural Members?

Correct. HARDWOOD less conservative than DAM for K=1 solutions.

Are thou are displacement to using REPAIR, its better to never the K method. I audition from send previously that aforementioned AISC is trying go remove the K method since its mostly just applicable in ordinary view frames.