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  • Users: JStephen
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  1. JStephen

    Bridge collapse- Brazil

    I ran across this incident while surfing Youtube a bit ago: https://www.reuters.com/world/americas/brazil-probes-risks-chemicals-after-tankers-plunged-off-collapsed-bridge-2024-12-24/
  2. JStephen

    ASCE 7-16 wind questions

    In ASCE 7-16, Table 26.13-1 categorizes buildings as enclosed, partially enclosed, or open based on area of openings Ao. Ao is defined as "total area of openings", etc. For openings that are screened, is that the gross screen area, or the net area through the screen openings? For example, on a...
  3. JStephen

    Nonwelded Parts per UCS 66

    Question: If you take a blind flange, and weld attachments for a hinge or davit to it, does it still qualify as a "nonwelded part"? IE, relatively minor welding unrelated to the function of the part. I can think of reasons to work it either way, but just wondered what typical practice is...
  4. JStephen

    Minimum anchor bolts for saddles

    For larger saddle-supported vessels, the saddles normally have provision for anchor bolts. But, in many cases, the anchors aren't actually required for wind or seismic action. In this case, the recommendation is "If Qo > QL, then no uplift occurs, and the minimum number and size of anchor...
  5. JStephen

    What are these? (odd little outbuildings)

    A friend asks me what these little buildings are for- any ideas? Woodside, CA, if that helps.
  6. JStephen

    Wind uplift on tank roofs

    Several revisions back, API added a wind-uplift load to API-650, and has revised that and the overturn criteria several times since. I was noticing recently that ASCE 7-16 has some wind-uplift requirements for tanks and tank roofs that are different from API-650, and that were not in ASCE 7-05...
  7. JStephen

    Bednar's Leg Design Method

    I've wrestled with leg designs through the years, and am just now looking through some of the details of Bednar's method. Reference: Pressure Vessel Design Handbook, 2nd Edition. The issue I find is than an unbraced leg subject to lateral loads has to have applied moments somewhere. The leg...
  8. JStephen

    Lifting lug vs shackle vs impact factors

    I'm designing a lifting lug. The specification calls for a safety factor of 2 and an impact factor of 2. So fair enough, if I have a 10,000 lb item, I add the impact factor and design for a load of 20,000 lbs, with a safety factor of 2. Or, I need design strength of 40,000 lbs. Then I'm...
  9. JStephen

    Flange welds, slip-on flanges

    Two questions have been bugging me about the little detail in UW-21 (ASME B&PV Code Section VIII Part 1) and the similar details in Figure 2-4. I think I asked these long ago, but don't recall ever seeing a definite answer, either. For that inside fillet, is corrosion allowance supposed to be...
  10. JStephen

    Duck Boat Update

    Updated info on the duck boat sinking a while back, with full report still pending: Press release: https://www.ntsb.gov/news/press-releases/Pages/nr20200428.aspx Report abstract: https://www.ntsb.gov/news/events/Documents/DCA18MM028-BMG-abstract.pdf
  11. JStephen

    Flush Manway Cover Thickness

    In API-650 Section 5.7.7.7 are equations for thickness of the cover plate for flush manways. The equations include a C factor, with is defined differently depending on whether h/b is > 0.5 or less than 0.5. Curiously, those criteria have flipped in the latest (13th) Edition. Anyone know what is...
  12. JStephen

    Dam Failure Vale Brazil Jan 25, 2019 (Update)

    The original thread: https://www.eng-tips.com/viewthread.cfm?qid=448577 The update- homicide and other charges filed against 16 people: https://www.yahoo.com/news/ex-vale-ceo-charged-homicide-231429267.html
  13. JStephen

    Tesla Autopilot Update

    There's been several threads on Tesla and Uber self-driving issues, most of which are now closed. I did just run across this article, which is newer news on a couple of incidents: https://www.yahoo.com/news/3-crashes-3-deaths-raise-080510771.html?guccounter=1
  14. JStephen

    Surface Finish Symbol

    I find the attached note on a drawing. I assume this means 250 micro-inches? But is that little cross a typical way to denote that? Trying to google that, all I come up with is the little check-mark-looking symbol, and never the italic cross.
  15. JStephen

    Definition of "seismic design uplift load"

    In the anchor bolt section of API-650, Section 5.12.13 requires design for three times the "seismic design uplift load per anchor", referencing Tb in 5.12.2. The Tb in turn is based on the uplift loads in Table 5.21. In that table, there is a "Seismic Load" line and a "Design Pressure +...
  16. JStephen

    Is 24" Sch 40 wall 0.687" or 0.688"?

    Yeah, I know, stupid question that doesn't make any practical difference. But I find the wall thickness of 24" Sch. 40 listed as 0.688" in some sources, as 0.687" in other sources. Did it change at some point? Or is it different in different standards? Or is this a conversion from...
  17. JStephen

    Pressurized Gauge Hatch

    Atmospheric tanks frequently have a hinged gasketed gauge hatch for gauging or tank sampling. Is anyone aware of any specific limitations on the maximum pressure at which those hatches can be applied, and the maximum pressures at which they can actually be used? Curiously, the gauge hatch...
  18. JStephen

    What's this from?

    Big piston rod seen alongside the road- picture with bike is for scale. So what did this come out of? We're not anywhere near the coast, so nautical origins are unlikely. It doesn't look that heavily built for its size, which makes me wonder if it's maybe out of a compressor instead of an...
  19. JStephen

    What kind of foundation is this?

    This is a screen-grab from a video where they're setting a very large vessel in place. The foundation has a row of anchor bolts sticking up for the vessel. But around the edge of the foundation is what looks like a row of bolts holding it down. Anyone know what's going on there? Just curious...
  20. JStephen

    Miami Pedestrian Bridge, Part III

    "Site management has requested that we limit the length of the other thread by forming a new one. This subject may require III, IV...." So here's Part III. Please don't post any more in Parts 1 and 2. Part I thread815-436595 Part II thread815-436699

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