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  1. gwideman

    SF Tower settlement Part III

    I think one point of confusion about the jacks is that dik is saying on this kind of jack you can set a hydraulic pressure that should be maintained, which translates to a force that the jack applies. This differs from a commonplace car jack, where you pump the fluid in to raise the car, then...
  2. gwideman

    SF Tower settlement Part III

    Likely of interest: Josh of the YouTube Building Integrity channel's recent video -- "Did I Uncover a $100,000,000 Mistake with the Millennium Tower "Fix"?" " https://www.youtube.com/watch?v=Xezg8PxVSYA. Josh critiques the rather small plates at the bottom of the threaded rods in the jacking...
  3. gwideman

    Miami Pedestrian Bridge, Part X

    But you are not presenting poor video. What you are presenting is fake video.
  4. gwideman

    Miami Pedestrian Bridge, Part X

    Please please read the previous forum posts about these interpolated videos. You are not analyzing evidence, you are analyzing the model used to interpolate, which means you are muddying the waters by claiming that these images tell us anything useful. As MikeW7 pointed out 28 Mar 18 22:52, the...
  5. gwideman

    Miami Pedestrian Bridge, Part X

    MikeW7: Back in the old days of Part IX (!) you were assembling videos that focused on when personnel inspected parts of the bridge. The appearance of the OSHA report perhaps drained some of your momentum, but I wonder if you have made any observations of whether the various inspections noted in...
  6. gwideman

    Miami Pedestrian Bridge, Part X

    ... but most important is whether or not it's interpolated in time, as you previously pointed out. If an assessment like Sym P. le's is based on a time-interpolated version, then it's just assessing the interpolation method and model, literally the morphing method that generates the...
  7. gwideman

    Miami Pedestrian Bridge, Part X

    No worries. I've deleted my comment to you as well.
  8. gwideman

    Miami Pedestrian Bridge, Part X

    Your entire post is spot on. For example, while it's important for OSHA or NTSB to use alternative software to cross-check the strength of the design, I hope that one of these bodies reconstructs how FIGG performed the design. I want to understand whether the errors are as simple as...
  9. gwideman

    Miami Pedestrian Bridge, Part X

    That "capturing the node" discussion stems from the "cracks" meeting just prior to the collapse. From that meeting: "Steel channels to 10/9 node & PT Bars to capture some of that force which is better than vertical support.". So something like this: This was deemed "better than vertical...
  10. gwideman

    Miami Pedestrian Bridge, Part X

    The north-south swap is annoying, but probably results from confusing wording of previous view direction statements on preceding photos. More concerning is their assertion on one of the photos that #11's lower PT bar sheared off, when photos at the scene show it attached to the deck, which is...
  11. gwideman

    Miami Pedestrian Bridge, Part X

    It think you may be referring to this informative post by SheerForceEng in thread part IV, 24 Mar 2018 22:40, responding to my questions as to whether the diagrams I sketched represented principles we would expect to see in the 11-12-deck connection, conveying the horizontal load of #11 to the...
  12. gwideman

    Miami Pedestrian Bridge, Part IX

    Yeah, I don't see those hoops either, but if they sheared they might be obscured under concrete dust in this picture. As for the roughening, that lack of such is mentioned in the OSHA report as one of the problems. But there was so much wrong with that connection it's hard to know which part...
  13. gwideman

    Miami Pedestrian Bridge, Part IX

    Aside from clearing up a lot of heretofore ambiguity about the initial failure location, what stands out for me about the OSHA report is that it doesn't reveal any new shop drawings showing extra steel, or FIGG calculations that might have been later and better and replaced the ones we've been...
  14. gwideman

    Miami Pedestrian Bridge, Part IX

    Actually that was jrs_87
  15. gwideman

    Miami Pedestrian Bridge, Part IX

    For those who have been following this story, and particularly the details of the #11-#12-deck area, these photos from the OSHA report finally give us a decent look at that area. Fig 62: Fig 63: As a side note: Fig 63 says that #11's lower PT bar sheared. Yet I don't think that matches what...
  16. gwideman

    Miami Pedestrian Bridge, Part IX

    Also MikeW7, you may find the OSHA report useful in correlating your video efforts with the report's description of who the personnel were. For example, page 75: "March 15, 2018 Two structural engineers from FIGG, Denney Pate and Eddie Leon arrived at the site approximately 7:45 am to examine...
  17. gwideman

    Miami Pedestrian Bridge, Part IX

    This question seems moot now, as the OSHA report just released contains this: "March 10, 2018 [...] As they [VSL] began to de-stress the PT bars of diagonal 11, cracks began to appear at multiple locations, most prominently at the construction joint of diagonal 11 and the deck and at the top of...
  18. gwideman

    Miami Pedestrian Bridge, Part IX

    Thanks MikeW7. But... "When Kevin Hanson noticed that the thin cracks veining a crucial connection in the Florida International University bridge had opened into gaping fissures, he pulled out his phone and snapped a few photographs. It was March 10, 2018, the day the prefabricated bridge had...
  19. gwideman

    Miami Pedestrian Bridge, Part IX

    That's some informative work you're doing. Any chance of adding some kind of date (or even better, date-time) overlay? That way we viewers could easily see how the inspections corresponded to other events in that critical week. Also, you mentioned Hanson reporting cracks that developed...
  20. gwideman

    Miami Pedestrian Bridge, Part IX

    I originally created this image at an early stage in this thread, and not knowing the dimensions, I drew the wireframe outlines of #11 and #12 far too wide. Their width should not encompass the two pairs of white vertical pipes/sleeves, a detail which is rather critical. (I realize this wasn't...

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