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  1. scofie

    Question in linear and nonlinear analysis

    I may be off here, but I think what you are seeing in your results is the effect of geometric non-linearity, NOT material non-linearity. Perhaps the ANSYS solution you are running includes both types of non-linearity. For thin walled pressure vessels, you should be running a non-linear...
  2. scofie

    Point Loads on Water Tank Shells

    Tincan, thanks for the reply. The antennas will be mounted on a 12 foot face width triangluar frame made up of pipe. It is not an antenna tower. The water tank is a 100,000 gallon water tank, 130 foot tall, 30 foot diameter, torospherical head, 1/4 inch thick plate. My point reactions at the...
  3. scofie

    Point Loads on Water Tank Shells

    I am designing an antenna array support frame to be mounted on top of a water tank (on the shell's crown). Rather than a finite element modelling of the entire tank shell, does anyone have any references for hand calculations and approaches for analyzing the tank shell for local loads...
  4. scofie

    Weeping Tile Blockage

    Isn't it possible that your problem could be moisture intrusion above ground into the block walls that travels down block cells to the wall base, which is your basement floor? As such, remediation would focus on things like exterior wall painting/coating deterioration, clogged roof gutters...
  5. scofie

    elastic materials'

    The response from Starmass is exactly correct. However, you may want simpler terms for understanding. An example of an isotropic material is steel or aluminum. Their stress-strain relationship can be simplified down to just two elasticity values, E and G. This is because when you compress...
  6. scofie

    Combined Compression/Bending in a Column

    How is it that 200 psi of compression stress causes the pole to fail the unity equation while ignoring 200 psi of compression does not? There is something wrong here. I get that the buckling stress is 9.35 ksi, so allowable axial compression stress is 4.88 ksi, so applied over allowable ratio...
  7. scofie

    Determining depth of existing caisson

    I recently had this type of work done also. I needed the depth of three existing drilled shafts for a telecom tower because the original foundation design drawings could not be found. Being in Florida, I used a company called GRL with offices in Orlano to do impact testing with a Pile...
  8. scofie

    Allowable Steel Stresses for Monorails

    Thanks for the comments from jgrek and dooron. Regarding jgrek's post, I agree that the 5:1 is for a static load while the design of steel support structure per AISC Code and the CMAA #74 standard are to include dynamic amplification factors on the static load. But the CMAA dynamic...
  9. scofie

    Grouting for masonry repair

    Not sure what the height of your wall is, but here is an idea. Since 1998, the ACI 530 Code for masonry has included a chapter on prestressed masonry. I know because I wrote the chapter. You could open up two top CMU and two bottom CMU faces, thread down a prestressing bar the full wall...
  10. scofie

    Allowable Steel Stresses for Monorails

    What is the governing standard for the allowable steel stresses for the steel support structure for a monorail with trolley hoist running on the bottom flange of an I-beam track, i.e. the I-beam, end support beams, hangers, etc? I am confused for a number of reasons. First, it appears that the...
  11. scofie

    Laterally Loaded Pile Criteria

    Focht3, thanks for the reply, comments and suggestions. With all of the pile foundations in service throughout the world, don't you find it a bit troubling that this basic pile lateral load analysis stuff is cutting edge? I can tell you that lack of a clear method of analysis with well defined...
  12. scofie

    Laterally Loaded Pile Criteria

    btangzh, your post highlights my very fustration. You make the statement "Generally, the RC piles have a lateral displacement limit of 1/4 to 1/2 inch, while steel piles will withstand a larger value." Why is this and how do you know? A reinforced concrete element is designed for...
  13. scofie

    Laterally Loaded Pile Criteria

    dgb, thanks for the comment. I guess I am finally seeing the big picture. The key is that one must analyze the pile with ultimate load conditions rather than service load conditions. I would guess that many engineers performing these calculations miss that key point and run the lateral load...
  14. scofie

    Laterally Loaded Pile Criteria

    Thanks for the comments. So I conclude that there is no particular lateral deflection limit required in all cases. However, I still am concerned with the issue of lateral pressure on the soil layers. For the design of a deadman anchor for a guy wire, one considers the lateral pressure applied...
  15. scofie

    Laterally Loaded Pile Criteria

    For some reason, I cannot seem to get a definitive answer to this issue, so I am petitioning the good readers here to help. For a laterally loaded pile, what is the maximum lateral displacement limit (in inches) and what Factor of Safety should one apply to that limit? Specifically, I am...
  16. scofie

    foundations for guyed and self-supporting towers

    You may wish to purchase the IEEE Standard 691, "IEEE Guide for Transmission Structure Foundation Design and Testing," published 26 December 2001. I have found it a helpful resource. As mentioned by Focht3, you can also review the Rohn catalog for tabular sizing of tower foundations...
  17. scofie

    High strength stainless steel pipe

    Actually, 304L stainless almost always has an actual yield strength exceeding 50 ksi, according to the vendors I have dealt with in the past. In fact, when they get a case where the buyer wants the yield to actually be around 30 ksi they special process the materail for lower yeild...
  18. scofie

    Stress Stiffening

    For thin walled vessels, if by the term "stress stiffening" you mean membrane tension behavior, this can be done with PATRAN/NASTRAN using the "non-linear static solution" (I believe it is SOL 105?). In PATRAN, you would want to click the toggles to activate large...
  19. scofie

    ACI 530 and unity equation

    I believe you may be mis-interpreting the ACI 530 Code. When you are checking the member as reinforced masonry subject to combined bending and compression, the stress state must comply with BOTH a) axial compression portion of stress less than the allowable axial compression stress with factor...

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