Not only that. On top of the sleeve are added 4 inches of slab with 10mm mesh poured right around the column (without any gap or membrane used), perhaps causing further fixity to the column. See:
My hope 2 years ago was to fixed the column right above slabs so moments would start above slabs...
Yes. They are 20mm stirrups..the footing floor is drilled so the 20mm bars can be inserted. see the following pics showing them in more details:
Note the red arrow showing 20 means it's 20mm bars.
The idea being that if the orginal column crushes and yet the particles are confined inside...
The Engineer of Record is the president of the structural firm. Since they design 7 projects at a time.. half of them high-rise. The president didn't check all details.. for example.. he didn't know how many bars in my beam. But ok. I'd try to explain it to their design leader. Before the ground...
The engineer on record said this problem is common in construction.. it occurs even on columns anywhere of 50-storey buildings. Once the epoxy company injected about 1 meters high of epoxy to a joint of a high rise. The designer on record said he forgot the concept of stress strain so just...
I also need to brace my frames. I'm discussing with my engineers who haven't done any. What do you mean Kootk that the laterally restrained bracing member must be connected to a diaphragm? See the image below.. the red X brace is not part of the structure but my hope to prevent rotations of the...
http://www.eng-tips.com/viewthread.cfm?qid=395487
Kootk.. after learning more about interaction diagram and boundary conditions in columns from BAretired and how to derive the formulas. I think the safest is to retrofit braces frames, shear walls or even using stair shaft as lateral resisting...
I edited above. When looking at side view. Consider the concrete cover is 40mm.. stirrups is 10mm.. bars is 20mm.. void is really between 100 to 200mm so 0.2x0.5 would be a conservative figure for approximate computations.
Earlier I was asking about moment magnification or p-delta. When there...
Oh it was that misunderstanding about "before epoxy void" where you thought I was referring to prior to epoxy put.. but I was saying the position before epoxy void. But I understood that part now here you were mentioning about stress at point b where as you put it.. "stress at point B would have...
Oh no. This is bad news. My designers forgot the meaning of stress-strain curve so don't know the behavior of epoxy. I'll have to convince them by sharing the principles and computations I learnt so they can try to look into this.
at what ratio for example is the moment right at zero so the...
Ah. When I said (before epoxy void). I was referring to before as in position.. not before as time :) Now I understood why you said there was no effect. I was reading about transformed section and kept thinking what you were thinking. Anyway. If you have time later, pls. go to the message above...
But at ultimate strength.. the concrete compressive block capacity is 0.85 fc' a b.. and if the fc' is changed to epoxy.. it compressive strength can become lesser.. so why did you say there is virtually no effect on ultimate strength.
Also what do you mean by bending stress? I was thinking of...
Thanks for the relationship or formula. After reviewing trigonometry and geometry. I kinda derive it after a day and your paragraph solidified the cconcept.
About the column subjected to pure moment with no axial component. Even on normal column with concrete. It's there too. . At balanced...
There is something odd about the interaction diagram. At balanced point and using statics and resultant..
Pb = 0.85fc'ab + As'fs' - Asfs
And As'fs' is same value to AsFs but opposite reactions. In other words the opposite reaction
literally cancel out. So at balanced point. How can you still...
Happy anniversary :) While you were celebrating and now while you were sleeping. I have used up a dozen papers trying to construct an interaction diagram of your column without concrete but with bars that is magically restrained from buckling and it seems it needs new formulas that don't have...
sponton, I've been pondering on what you said above. Yes. I'm talking about moment unbalance from column at sides of building because of
beams framing into it at one side only.. it has nothing to do with actual eccentricity.. only virtual.. virtual in the sense that
you can only relate moments...
Because of the word wrap problem. Let's continue in this thread BAretired, sponton and others
http://www.eng-tips.com/viewthread.cfm?qid=395487
Btw.. in the computations above. I entered all formulas in excel from the book and I crosscheck it via the book examples to see
that I entered the...
To BAretired (sponton and others). This is continuation from thread http://www.eng-tips.com/viewthread.cfm?qid=395252 because of word wrapping problem there.
BA you stated before when we were computing for pure axial load that "Note: The above calculation assumes uniform strain throughout...
After trying many numbers in excel for the interaction diagram. It seems clearer now how to relate
the compression block, the compression bars and the tension bars. They are interrelated and the
following formulas and computations seem to relate them all and it may actually be able
to solve...
I have reviewed the book on the interaction diagram for half day. And the following is what I comprehend. Please
correct me if i'm wrong.
1. Concrete stress-strain diagram is for elastic range only at 0.0005.. for near strain limit of 0.0021.. you can no
longer use the stress-strain curve
2...
