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  • Users: gwynn
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  1. gwynn

    Flare weld to Prestressed Girder Top Flange shear bars

    If you can get the tie tight to the top flange, you can get reasonable capacity out of attaching to the stirrups. Not at the distance the conceptual drawing seems to show though. And I second your thoughts on weld capacity. My preferred detail is to cast sleeves into the web, just below the top...
  2. gwynn

    Miami Beach, Champlain Towers South apartment building collapse

    A bit off topic, but most of the bridge decks locally have gone to stainless or low carbon/chromium bars lately, with GFRP bars used in a few places. Epoxy coated bars are now only permitted on low volume roads here.
  3. gwynn

    What to learn for a bright future in the industry (Bridges)

    Turning aside from the discussion of 3D modeling for a moment, one of the things I would suggest to anyone planning a career designing bridges is to spend some time working on the construction engineering side of things. This is probably the best way to understand how design decisions impact...
  4. gwynn

    Bridge failure during launch, Umeå, Sweden.

    The term bridge launch is commonly understood among the North American bridge designers, erection engineers and bridge contractors I know. The piece-by-piece method of bridge erection is referred to as stick built locally (only applicable to larger multi-span bridges). A few comments from the...
  5. gwynn

    Transporting Stress Limits & Loads Specification

    CSA-S6 (the Canadian Highway Bridge Design Code) limits stress in precast girders during transport and erection to 0.5fcr in tension and 0.6f'c in compression. The PCI manual methodology mentioned above for evaluating pre-stressed concrete girders during transport and erection is also accepted...
  6. gwynn

    Difficult Concrete Slab Pour

    Width has no effect. For a fluid pressure is dependent on the amount of head only. Typical practice for wall forms against existing walls, from what I see here, would be to Hilti some coil rod into the existing walls, add B1 coil ties or similar and attach a wood form on the open side of the...
  7. gwynn

    Forming concrete slab by hanging soffit formwork from steel beams

    This is how most bridge decks for steel girder bridges are formed. Concrete girder bridges are a little bit different, in that the girders are concrete. Dayton Superior and National Concrete Accessories (NCA) supply the hangers you are thinking of. Just make sure that the beams can handle the...
  8. gwynn

    R&D ideas for structural engineering

    I would go with an in depth cost benefit analysis of making the top flange of NU girders 2" thicker.
  9. gwynn

    Curved Deck on Straight Parallel Beam Design

    In reference to the cross frame "fit" comments above, I believe many of the NSBA and AISC comments on this reference NCHRP report 725, which is available in it's entirety here: http://www.trb.org/main/blurbs/167646.aspx It also give guidelines on when different methods of analysis should be...
  10. gwynn

    Lifting Beam Design

    Apologies, I had thought it was in the "Structural Stability of Steel" text by Galambos, as that has been a go to reference for the "other rational methods of analysis" CSA S-16 allows in regards to stability. I also remembered it being laid out in more depth. The text I should have referenced...
  11. gwynn

    Lifting Beam Design

    To add to the above from both SlideruleEra and Lomarandil, Closed sections (generally pipe) are common for both spreaders and lifting beams in my experience. If it works with a 12" HP section though, the contractor has a bunch lying in a yard somewhere. The latest edition of Galambos does deal...
  12. gwynn

    Lifting Beam Design

    delagina: You are incorrect that all spreaders are bought off the shelf items. Custom spreaders are very commonly engineered items for those who work with/for construction companies. The ASME standard mentioned by JStephen above (design of below the hook lifting devices) is the go to...
  13. gwynn

    I have a situation where the floor

    Is the bolted connection between the truss and beam enough that you have moment fixity between the two for the offset from centreline of beam to end of truss?? If so, if you take the truss as simply supported to the centreline of the beam, what is the rotation in the truss at the centreline of...
  14. gwynn

    Tension and shear force at top of foundation wall from braced frame

    I agree, introducing field welding where there was none before generally doesn't make people happy. You could have drilled and tapped holes in the embedded plate, but then you would need to have a site survey after pouring the slab and prior to fabrication of the brace assembly.
  15. gwynn

    Unity check for pin connection?

    It depends on what the application is, and if the pin is going to see significant rotations and how many cycles of load and/or rotation (fatigue/wear considerations). CSA-S6 gives the interaction equation for bending and shear stress in a pin as Mf/Mr+(Vf/Vr)^3 < 1, with Mr based on elastic...
  16. gwynn

    What are the popular software for civil engineer currently?

    @CCPE All of the calculations in Profis are based on using Hilti anchors and/or epoxies. You should not use this program to do anything other than determine which Hilti anchor or epoxy, and embeddment depth to specify. Hilti wrote the program after the changes to schedule D made the tables...
  17. gwynn

    Lateral Design of Steel Stairs

    If the deflection at the top of the stair tower is that small, I would determine what forces are induced in the stair tower by that amount of deflection. Design the stair tower for those forces (or 5% out of plane loads, etc., whichever governs). If displacement loads govern, this would be...
  18. gwynn

    Fall Protection with Wind Loads

    I agree with Dave, in that you would not have a worker there in a high wind event. Even on the rare chance you did, the peak load from a fall arrest system is an impact load and the peak load from a wind storm is a three second gust. To combine the two is being overly conservative given the...
  19. gwynn

    Canadians stranded after bridge splits amid intense cold

    Here is a link to the 2015 report that resulted from the original inquest (I am linking the English translation, not the French original). If it's a members only document, I can dig up the link from Manitoba which might not be. APEGA seems to not have a direct link to it...
  20. gwynn

    Canadians stranded after bridge splits amid intense cold

    I don't know the details of what is happening in Quebec. Only what was in the email news notification from my local association, which said that they had been placed under temporary government stewardship.

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