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Recent content by BridgeEngineer21

  1. BridgeEngineer21

    Open Spandrel Arch Bridge with Solid Exterior Arch

    The arch is a compression member - shouldn't you model it with shell elements rather than plates? Then you can just take the in-plane cross sectional forces and check compression/buckling.
  2. BridgeEngineer21

    External anchorage of reinforcement - is this feasible?

    Agreed. Propping the slab is also an option under consideration. But this anchorage idea is not my approach, it's something the contractor is asking to do. So I should only say no if I have a good reason it won't work.
  3. BridgeEngineer21

    External anchorage of reinforcement - is this feasible?

    Yea, that was my thought. The bond fails, so the plate picks up the tensile load and transfers it back in compression on the side face of the slab, providing the necessary anchorage.
  4. BridgeEngineer21

    External anchorage of reinforcement - is this feasible?

    Sorry, I'm not going to post anything more detailed due to sensitivities of the project. All I can say is the loading and geometry is complex and probably not what you're picturing. It's not really comparable to the behavior you'd see on a typical bridge deck with staged construction. There...
  5. BridgeEngineer21

    External anchorage of reinforcement - is this feasible?

    It's definitely not a simple cantilever, and the reinforcement demand can't be easily determined based on rules of thumb or hand calcs. It's a two-way slab with complex geometry and openings, experiencing large axial forces and bending in both directions. There is a significant demand for...
  6. BridgeEngineer21

    External anchorage of reinforcement - is this feasible?

    But again, as I said, if the situation i described is getting you hung up then just forget about it. I really just want to discuss the general question of external anchorage. Not why or whether the external anchorage is needed, but if it's feasible at all.
  7. BridgeEngineer21

    External anchorage of reinforcement - is this feasible?

    Ld required is 1000mm. Ld available is 0mm.
  8. BridgeEngineer21

    External anchorage of reinforcement - is this feasible?

    Yes, that's one example of a situation where you need a hook to anchor. So take that situation then. Instead of a hook, do you see a reason it couldn't be anchored externally? Since this is a temporary condition, ignore deterioration of the external plate. Sorry for the terrible sketch on my...
  9. BridgeEngineer21

    External anchorage of reinforcement - is this feasible?

    Thanks for the input everyone, much appreciated. The contractor has already identified some materials they'd like to use for this, though the threaded rebar gives me the idea to look into a possibility of rebar threaded beyond the, so I could fit a plate and nut plus a coupler behind it like I...
  10. BridgeEngineer21

    External anchorage of reinforcement - is this feasible?

    You can't count on the full capacity of the bar to be activated and acting compositely right at the tip of the bar. This is why we specify anchorage lengths, hooks, bends or headed bars.
  11. BridgeEngineer21

    External anchorage of reinforcement - is this feasible?

    Thanks HTURKAK, but the coupler is not the problem. We know the couplers we're going to use. The question is, can a rebar be anchored by being bolted to a plate bearing externally on the surface of the concrete (rather than traditional methods of bonding over a straight anchorage length, or...
  12. BridgeEngineer21

    External anchorage of reinforcement - is this feasible?

    Hopefully this can clarify. The structure is quite complex (It's a large project so I am being purposely vague to avoid giving away what the project is) with very complex loading conditions and geometry during this particular construction phase. So the demand at the tip of the reinforcement is...
  13. BridgeEngineer21

    External anchorage of reinforcement - is this feasible?

    Ahh, sorry for the confusion. No this is a slab in a complex building structure being built in stages, which will have construction vehicles and loading running on it prior to casting the adjacent portion of the slab. So its a cantilevered piece of slab, and there's a large demand on the top...
  14. BridgeEngineer21

    External anchorage of reinforcement - is this feasible?

    Thanks, but that one is not for a structural application. This external plate needs to be able to transfer the anchorage force (tension in the bars) into the concrete through bearing on the surface.
  15. BridgeEngineer21

    External anchorage of reinforcement - is this feasible?

    I have a situation that I can't seem to find any examples of in practice. During staged construction, a slab is loaded right to the edge, utilizing the primary longitudinal reinforcement. These bars will eventually be coupled and continue into the next stage of the slab (figure 1). But...
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