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  1. aggman

    Loctite on Structural Bolt?

    We have never used loctight. I would be concerned that it wouldn't actually work right with the differences in the threads between structural and machine bolts. For vibration issues we have used anco lock nuts which are ok, but not great.
  2. aggman

    Corrugated Pipe Reclaim Tunnel

    I don't recall exactly what the foam was but it seems that we were looking for something that expanded but didn't harden. My mind is saying like foam insulation but that stuff hardens so it's not ideal. We were worried about rock pushing it back and allowing leakage but it never was a problem.
  3. aggman

    Corrugated Pipe Reclaim Tunnel

    Ideem, Just an FYI, I have been involved with several pipe to bunker transitions like you have designed for stockpile reclaims. I have seen failures in your design where you see excessive diagonal cracking in the corners. This is prevalent on larger diameter tunnels because of the amount of...
  4. aggman

    Combining Pad Footings in the Field

    I would agree with the bond break and would probably insist on that if they don't want top steel. It's pretty simple to do, even if they place plywood at the theoretical footing ends. Down the road when we are all dead someone will want to increase the footing size for some unknown reason or...
  5. aggman

    Pipe Column Transition

    KootK, I would be interested in what it has on the transition analysis. I have sorta moved on from it for the moment, but I still have to resolve the base plate design. In regards to the anchors, have you ever looked at the thread bars in fatigue? I've got some low cycle fatigue, which is...
  6. aggman

    Pipe Column Transition

    Thank you for the link strutSU10. That's more or less where I am in my head at this point. I'm settling in on a ring to locate the 36 anchors (has to be a factor of (9) because of the upper ring connecting to the slewing bearing uses 45 bolts and I need stiffening gussets to line up). The ring...
  7. aggman

    Pipe Column Transition

    I have been working through the design on a single pipe column fixed at the base to a circular concrete pier. The column is 42" in diameter. I am having some trouble with the anchorage with regards to concrete bursting on the anchor head. This is being controlled by tighter than normal anchor...
  8. aggman

    Gravel/sand pressure?

    I would approach this with Bin Theory. If you have Gaylords structural engineering handbook it can walk you through it. Other references are ACI 313-97 which addresses design and construction of concrete silos and stacking tubes. These all follow Jannsen theory. The hard part is going to be...
  9. aggman

    Natural Frequency of a structure and foundation.

    bsrd, It would be pretty common to have the structure pass through the natural frequency during start up and shut down. It will shake for a few moments, particularly on shut down as it is a coast down process. The start up will be more or less non-existent. I would take the time to...
  10. aggman

    Natural Frequency of a structure and foundation.

    In regards to the natural frequency range the answer is that it depends. If you are above the range, additional mass (material transferred, etc.) will lower the frequency and could bring it right into play. If you are lower than the added mass will not hurt you, but it will pass through it on...
  11. aggman

    Anyone notice this a lot on foundation drawings now?

    As a general rule we get soil reports on 20% - 30% of the jobs we do. I wish it was on all of them, but we can lead the horse to water, but can't make them drink. We build industrial (mining) structures. As a rule we try to visit the job-site, look at whats going on, and try to adhere to...
  12. aggman

    Support Members in Stockpiles Loading

    First answer...Good luck finding references other than your typical soil mechanics books. I've been doing this type of work for 15 years and haven't found much. On the balance, I would tell you to be very conservative with your designs on these. We have seen a lot of piers moved, cracked...
  13. aggman

    Should I stamp my own work as an Employee (Structural Engineer)???

    As far as responsibility you are responsible with or without stamping the drawings, with or without a P.E. Lawyers will hunt out everyone involved, even if you are no longer employed so you can't hide from it. It's just the nature of the beast. I believe the person stamping should be the...
  14. aggman

    ASCE 7-10 - Wind Load on Box Truss - Fig 29.5-2 or 29.5-3?

    We use the trussed tower design methods. The lattice framework is appropriate for single sided frames, not multiple frames. The trussed towers accounts for member shielding on the back side. Back some years ago we were always debating this in the office (and with some other consultants)...
  15. aggman

    Large Diameter Tubular Conveyor Galleries - Reference?

    I have designed a few of these. Their is some information in the structural engineering handbook by Gaylord. Troitsky is probably the best reference. He also references E.H. Baker "Structural Analysis of Shells". Baker has a pretty thorough review of the subject and I'm sure Timoshenko has...
  16. aggman

    Machine Seismic Load?

    I don't know the rigidity of your press, but I would likely say that this meets 15.4.2 (Rigid Nonbuilding Structures). Chapter 13 only applies to components mounted and supported by building type structures where the supporting frame is not specifically designed to carry the component. (Like a...
  17. aggman

    Shear Friction - Concrete to Rock

    JAE, We have used the ACI shear friction provisions for concrete to rock interface several times. Nothing along the magnitude of what your talking about, but definitely designing for loads of several hundred kips. We have not had any failures of our stuff that we designed but we have fixed...
  18. aggman

    Complex beam bending problem

    For a statically indeterminate beam like this I would use moment distribution. It is very straight forward to solve this way. You can google (Moment Distribution by Hardy Cross) and you will get a bunch of information and descriptions of how to use the method. This is of course assuming you...
  19. aggman

    Deflection and Moments for Plate (Two Simply Supported Edges and Two Free Edges)

    A plate is nothing more than a beam when spanning in only one direction. Any differences in actual results based on the "plate" verses "beam" are negligible for practical results.
  20. aggman

    Deflection and Moments for Plate (Two Simply Supported Edges and Two Free Edges)

    To me for the question of thin verses thick to even be considered we have to establish if the ends are restrained against lateral movement. If the ends are free to translate then once the plate fails in bending then it will collapse since axial tension can not be held. If the ends are...

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