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  1. JStephen

    Low Concrete Testing

    I don't know what the normal solution is to low concrete breaks. It has come up only a time or two in my experience. In those cases, the foundation was still structurally sound with the lower strength, it just didn't meet the customer specification. And the solution was a pricing adjustment...
  2. JStephen

    California high speed rail

    I was riding my bike around a couple of weeks ago, and found myself on a nice road that terminated at a closed gate. I assume it was the main road going into the Superconducting Supercollider or whatever it was they were building here in north Texas 20 or 30 years ago. To keep spending money on...
  3. JStephen

    Pickling & passivation is required for API 650 SS storage tank bottom plate soil side weld joint butt weld configuration without back strip or not

    I don't think there is anything in API-650 that would require pickling and passivation. That would be a contractual issue if required.
  4. JStephen

    Footing uplift safety factor

    I think the issue here is simply that "Factor of Safety" has to be defined clearly to have any meaning. So, for example, in your Method 3, the "Factor of Safety of actual pullout force relative to pullout force causing uplift" is indeed that 4.2 factor. But if you have multiple loads, multiple...
  5. JStephen

    Design Code for Buried Tanks – UL-58 or ASME VIII?

    UL-58 is commonly used for underground tanks, but they are usually considerably smaller than the tanks you're proposing. If you can contact some UL-58 tank suppliers, their input might be helpful I'd say use of ASME is reasonable, it may or may not be required. External pressure from water and...
  6. JStephen

    Welder Qualification

    I believe the welder who welds the test sample is also qualified by that- stated in the code somewhere- but I don't have that handy to look it up.
  7. JStephen

    Anchoring scissor car hoist/lift

    The anchors may be more so that the unit doesn't slide out of the way when you try to drive onto it, rather than for uplift. If you could park a car so the wheel was right at the very end of the unit, I can see the need for anchors, but it's not clear what the original design conditions for this...
  8. JStephen

    Typical Details

    What I see is the use of "typical specs" that have user notes saying to "check this option, check that option" etc., and instead of the users actually reading or checking any of that, it just all gets copied into the specs and sent out for bids.
  9. JStephen

    Tank Overturning Stability Criteria

    I think one of the principles being used here is that if you have two independent effects, you don't necessarily assume that both happen at the same time. So, for example, for vertical and lateral seismic acceleration, both are considered, but one is reduced when combined with the other. With...
  10. JStephen

    Electric car ship fire.

    I'm just now reading through this thread, and my idea was tow it to shallow water, sink it until the fires go out, then raise it again. Looks like they omitted the "shallow water" part, though.
  11. JStephen

    ASCE 7 wind load for round irrigation tank

    "Does this mean that in order to compute drag and overturning moment on the tank I should only include the WINDWARD area, so that Af = HxD?"- Yes "Should there be some kind of additional consideration taken into account in that case?"- None that is required by ASCE 7-16 at least. There are...
  12. JStephen

    Wind Load

    There's potentially a bunch of stuff vibrating up there, as well as the overall structure. Why the "half the wind load value"? At 15', if it blows over, that's a bit of hazard. Can an athletic person jump up and grab a hoop?
  13. JStephen

    Coaxiality tolerance for the welded structures

    Tolerance would depend on the application, I assume. You could assume an offset and check resulting moments and stresses in all members to find the effect of tolerance. Perhaps limited by cosmetics, by measuring and fit-up gear available, by tolerances in tube roundness.
  14. JStephen

    Stairway forces on Shell

    I think all of the above. Normally, when I put together a calculation package, I include major items, but there are a lot of little items that I either know don't really need checking or that I have design spreadsheets for but don't include them in the package. There are ways to check stresses...
  15. JStephen

    ASCE 7-16 15.4.4 - Approximating Seismic Period

    A while back, I was checking this on a tank. I tried distributing loads proportional to the deflections and iterating to a solution. Result: A lot of extra work and almost exactly the same frequency. More clarity would definitely be helpful with the way it's presented there, though. For...
  16. JStephen

    Index for 12 page calculations?

    Make each separate line of the calculations a separate entry in the index, so you wind up with a 12-page index?
  17. JStephen

    Shaft Failure in Translation Gear Reducer of Bucket Wheel – Need Help Identifying Cause

    I would not expect them to put a student in charge of analyzing high-dollar failures in expensive equipment, so this sounds a lot like homework...
  18. JStephen

    Leaning Pedestal (Octagonal) Home

    It's a pedestal house, and the small base tilting and being amplified in the whole house makes sense to me. However, there seems to be an entire rectangular section built into it, and then there're posts from the house itself and from the deck. Is all of that stuff tilting uniformly to match...
  19. JStephen

    Convert Gas Oil Tank to unconverted oil product from hydrocracking unit

    Some general items- also see API-653. You are proposing a "change of service": Changes in specific gravity vs shell design, foundation design, seismic design, floating roof design, manway cover design Requirements for floating roofs, internal or external Requirements for venting, emergency...
  20. JStephen

    Machinery supports vs. structural steel

    The last time I checked, a "structure" was defined as "that which is built", so it includes houses, cars, televisions, and kazoos, so not an especially useful definition. In ASCE 7, tanks fall under "non-building structures" (as do silos, pressure vessels, etc) but are still not considered as...

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