Do you have any reference for your comment? It seems to conflict with my reference by Mcgregor, he said the "once torsional cracking has occurred, the concrete in the center of the member has little effect on the torsional strength of the cross section and hence can be ignored" (see also figure...
Going back to pure torsion. Is your "slip" got to do with the concept of "angle of twist" ... were you talking about the angle of twist being related to the stiffness such that in cracked concrete, the angle of twist is larger in value hence stiffness poorer? What is the technical word for your...
I wasn't referring to combined torsion and shear failure.. but shear failure alone.. specifically diagonal inclined shear failure. How do you characteristize the prior and post stiffness of beam in diagonal inclinde shear failure (without taking into account torsion so try to remove the torsion...
I mean in the shear diagonal inclined failure mode that is not torsion failure.. what is the difference between post cracking stiffness and pre cracking stiffness of the beam? Is it somewhat still similar? At diagonal inclined cracking (not Torsion related), there is still Vc or aggregate...
If that's the case.. how do you explain this passage ""At torsional cracking, however, a large twist occurs under an essentially constant torsional moment, resulting in a large redistribution of forces in the structure (Collins and Lampert 1973; Hsu and Burton 1974)" Well. If there is still...
In diagonal shear crack.. when this happens.. the stirrups were being engaged so you still have shear capacity by Vc + Vs.. Is it not torsion cracks are similar where after it occurs.. torsion is resisted by the stirrups? But in ACI 318 there is this passage "At torsional cracking, however, a...
Effect of differential settlement is like overloading certain columns and joints and there should be shear failure from reactions transferring elsewhere.. this should be dangerous. Can't creep of concrete cause this effect too?
sometimes you are told to put lean concrete (without aggregate) below foundation if the rock below is not level. But won't the lean concrete itself settle causing settlement problem? How many inch does a 4 inch thick lean concrete base settle?
After reading it over and over again. I understood it already.
For normal residental and not so large span loadings. The difference in positive midspan moments between forced pinned secondary beam and full moment connection is not so large.. so even if you don't make it pinned.. the positive...
BA. You haven't mentioned the torsion stirrups.. if the girder suddenly cracks in torsion, and there are sufficient torsion stirrups.. would the secondary beam lose its end moments?
Let's review the possible scenerios.
1. If the secondary beam end is designed as pinned with weak top bars...
If the torsional cracking in the edge girder occurs.. won't it engage the torsion stirrups increasing it's fy until yield? Without yielding.. there would be no redistribution of forces.
And you assumed the torsion stirrups have yielded? Assuming it does. Let's imagine you are hanging on tree...
Thanks for the sections. I'd like to inquire specifically about R22.7.3b. It is stated there that
"(b) The torsional moment can be reduced by redistribution
of internal forces after cracking (22.7.3.2) if the torsion
results from the member twisting to maintain compatibility
of deformations...
I was thinking you had to intentionally yield the top bars before casting the beams but in truth you just used smaller bars to ensure it would yield should loadings or torsion in the edge girder are being engaged. This is a clever idea. Many thanks guys.
But my mentor and his team who have...
If you design the secondary beam as pinned.. it means simply putting more midspan bottom bars for moments or also creating semi yielded top bars at the joint as described by TEH to create truly pinned connection? Can anyone share exactly the chapter and passage in ACI318 so I can look at it...
To those designing 2 to 3 storey building with stiff soil profile.. I heard they are in resonance.. do you notice this too and what is your experience on it? Any quick formulas to check the resonance values of the stiff soil and storey height? Geotechnical engineers usually just give you the...
"Tuff (from the Italian tufo), also known as volcanic tuff, is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is compacted into a solid rock in a process called consolidation. "
You can't dig into Tuff rock with...
Does JAE have the above in mind too about allowing it to flexurally crack or have ductile yielding at the top (negative moment) (both in my mind dangerous) or does he have another pinned method when he confidently stated in
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