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  1. RobertEIT

    A seemingly simple question but in fact very difficult?

    MaddEngineer: This is a very common design issue in real world. Actually, I, myself often have to estimate this kind of anchor tension in my daily design work. If it is similar to your past PE exam question, it is totally an accidental coincidence. Come back to this question, I have to...
  2. RobertEIT

    A seemingly simple question but in fact very difficult?

    Please see attached file. The base plate is adequate. the 300 kips-in overturn moment can be in any direction. Required: What is the maximum tension (kips) in anchor bolt. Note: only left hand drawing is in original question. The right hand drawing is based on my analysis, it may not be...
  3. RobertEIT

    What does crack stress in handling a concrete pile really mean?

    It does not give any information on this either. It just ask what is the crack stress in handling a concrete pile with fc'=xxxx.
  4. RobertEIT

    What does crack stress in handling a concrete pile really mean?

    PEinc: It seems very few people visits the Concrete Pile Engineering forum and even less people responds to the question, therefore I posted here seeking for help. StructuralEIT: Yes, my first reaction is also to consider fr=7.5(f'c)^0.5 as the crack stress. But the maximum value it gives...
  5. RobertEIT

    What does crack stress in handling a concrete pile really mean?

    Thank you StructuralEIT for your response. Suppose in a test you were asked to answer how many psi the crack stress in handling a concrete pile is and the only information given to you is the concrete fc'. Would you think it is a bogus question?
  6. RobertEIT

    What does crack stress in handling a concrete pile really mean?

    I checked in ACI318 and PCI Handbook, but can't find such a terminology crack stress in handling a concrete pile. Is this "crack stress" during handling a concrete pile a bogus terminology and the question asking for the "crack stress" during handling a concrete pile a bogus question...
  7. RobertEIT

    calculation of slide downward soil load on piles?

    It might be a very simple question. But..., too many various kinds of tricks make me nervous. I would like to make sure there is no tricks in calculating the slide down soil load on piles. Please see attached word document, is vertical load of soil on the pile simply equals 9.49 kips? Thanks a lot.
  8. RobertEIT

    Angle end condition question.

    Sorry, I forgot to mention that these angles are purely compression members. I would like to know what "K" value is considered the right value among most of you structural eng. guys. K=1.0(pinned)? or K=0.65(fixed) or some value between 0.65 to 1.0? Thanks.
  9. RobertEIT

    Angle end condition question.

    Please see attached file. My question is in real world design, what kind of end condition you guys will take it as (end condition in Figure 1 and Figure 2)? Thanks a lot for your precious oppinion.
  10. RobertEIT

    how to calculate crack stress in operating a concrete pile?

    jrisebo: I can't find anywhere in ACI or PCI at which crack stress in operating or handling a concrete pile (or prestressed concrete pile) is discussed. All I can find is the discussion of permissible stress at transfer or in serviceability stage etc.
  11. RobertEIT

    how to calculate crack stress in operating a concrete pile?

    Well, I am seeking the NCEES recognized formula, I believe there is only one formula which NCEES accept as the correct answer, My formula comes from Donald P. Coduto's book << Foundation design>>. But I don't know if it is NCEES accepted correct formula. That's the big problem.
  12. RobertEIT

    how to calculate crack stress in operating a concrete pile?

    Can anybody please tell me how to calculate the crack stress in operating a concrete pile? Is this crack stress equals 6*sqrt(fc')? Say if the concrete compressive strength fc'=6000 psi, the crack stress equals 6*sqrt(6000)=464 psi? Thanks a lot for your help.
  13. RobertEIT

    A tricky question

    This kind of trick is more like a kid's game. Don't see much practical meaning. Hope NCEES will not bring such kind of trick into their exam.
  14. RobertEIT

    A tricky question

    This isn't a tricky question, it's very simple. reaction A: X=11.25 kips, Y=1.125 kips reaction B: X=-11.25 kips, Y=1.125 kips load in strut = sqrt(11.25^2+1.125^2)=11.31 kips delta strut = 16.48'*11.31/E/A from delta strut, the deflection of hinge C can easily be derived. Am I take it too...
  15. RobertEIT

    How to Use torsional constant &quot;J&quot; in AISC-13th to get torsional stres?

    I know for many AISC steel shape, torsional constant "J" differs graetly from polar moment of inertia. But are we supposed to use torsional constant "J" in AISC-13th steel shape the same way as polar moment of inertia to get the torsional stress of a AISC steel shape, i.e. Tau=T*r/J? Thanks a lot!
  16. RobertEIT

    Stress-----Always refer to service load?

    Sorry, kslee, I can not post the exact question. It will violate the agreement we signed with that organization. By asking this conceptual question, I did not violate the agreement. It related to the event happened in April 24. I suppose many engineers in U.S know what event happened in U.S...
  17. RobertEIT

    Stress-----Always refer to service load?

    Well, The big problem is that "somebody" is a well known authorized organization. We were unable to ask what he want from us --- service load based stress or factored load based stress. We can only guess what he want from us. You know what I mean. If you were under this situation, which load...
  18. RobertEIT

    Stress-----Always refer to service load?

    We know that ACI requires to use LRFD to do design calcs. But now if somebody asks for the shear stress in a reinforced concrete beam, say if we were given 10k dead load + 20k live load, should we use service load 10k+20k to calculate the shear stress or should in the beam we use factored load...
  19. RobertEIT

    Flexible roof diaphragm shear wall load distribution question?

    Please see attached diagram, we know that for flexible diaphragm, if two shear walls are not in a same line with shear force as in Fig.1, the shear load is distributed to these two shear walls by their tributary area. But what about the two shear walls are in a same line in the shear force...
  20. RobertEIT

    Bolt bearing strength, AISI-2001 vs.AISC-13th

    With AISI code, when calculating the bearing strength the inside sheet of double shear connection will have a higher coefficient (1.33) than single shear and outside sheets of double shear connection (1.0 with washer or 0.75 without washer) giving a higher bearing strength for the inside sheet...
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