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Recent content by BacBac

  1. BacBac

    Cast-In Starter Bars vs Post Fixed Epoxy - Edge Breakout

    @ANE91 I meant the concrete breakout failure that is worse when your post-fixed rebar is close to the edge. Please see snapshot below for clarity. I'm assuming this is referring to ACI? Could you please guide me to which clause you are referring to? Yea, we will be specifying this to be done...
  2. BacBac

    Cast-In Starter Bars vs Post Fixed Epoxy - Edge Breakout

    Hi All, Does anyone know why the effect of edge breakout is more severe in post-fixed rebar with epoxy compared to cast-in rebar? Say you're drilling a post-fixed rebar the same length as what the development length of the cast-in rebar, if you check it in Hilti or similar software, the...
  3. BacBac

    PT Pan Stressing Tendon Elongation

    @Tomfh Yes, they are constantly out for pan stressing. We have asked the contractor to ensure that the hydraulic jack is calibrated correctly. For instance, we have 27m long tendons adjacent to each other with pan stressing on one and edge stressing for the adjacent, the elongation result we get...
  4. BacBac

    PT Pan Stressing Tendon Elongation

    Hi All, Structural engineer from Australia here. I'm currently working on the construction phase of a project where the floor system is PT suspended slab, and our office is detailing the PT slab. The typical tendon length on this project is >24m. The design was completed using popular software...
  5. BacBac

    Strut-Tie - Tie Development at Nodes (Starter Bars)

    @KootK Thanks KootK for all the replies, very insightful. I feel the same thing in the industry. You mostly end up doing what your managers asked you to do, and the seniority usually wins. When you start arguing too much, you're seen as not a team player, and it hurts your career. It is what it...
  6. BacBac

    Strut-Tie - Tie Development at Nodes (Starter Bars)

    @KootK That's what I thought when I first heard it as it even contradicts with EQ design principle as you don't want to over reinforce the plastic hinge. But what surprises me is that his previous company always does it that way, and the previous company is actually a well-known consulting firm...
  7. BacBac

    Strut-Tie - Tie Development at Nodes (Starter Bars)

    @KootK Thanks for your insight. Unfortunately, my new manager insisted to have larger starter bars on all starter bars where there's tension due to bending unless I find a justification not to. Seems like his previous firm always put larger starter bars under core, but I just haven't seen other...
  8. BacBac

    Strut-Tie - Tie Development at Nodes (Starter Bars)

    @KootK Thanks for the recommendation. What do you mean by “really gotta tell an STM story”? I’m just wondering to find a way to justify the current typical detail (where cogged/hooked starter bars match the size of wall vertical bars) actually works before I introduce unnecessary changes...
  9. BacBac

    Strut-Tie - Tie Development at Nodes (Starter Bars)

    @rapt Thanks, rapt. In short, are you saying the answer to these 2 questions is yes if we follow the standard hook/cog detail as per the typical industry practice?
  10. BacBac

    Strut-Tie - Tie Development at Nodes (Starter Bars)

    @hardbutmild Thanks. I'll research more on increased bend diameter to allow for better anchorage. @rapt Thanks for explaining the 10db bent for me. It's noted that we need to develop the strength at the node, but as per the original thread here...
  11. BacBac

    Strut-Tie - Tie Development at Nodes (Starter Bars)

    @hardbutmild Thanks for the comments. AS3600 also states that if the diameter of the bend is >10db, then the development of the bars can be assumed to be continuous. For low rise building, the thickness of the wall is typically 200mm, you barely can fit the U-Bars with 10db internal bend, which...
  12. BacBac

    Strut-Tie - Tie Development at Nodes (Starter Bars)

    @bugbus I agree the top one is the general consensus. The commentary of the AS3600 also makes it quite clear. My issue with the starter bars is that since we only have cogs at the nodes ends, and the STM principle requires tension is constant at nodes face, should we put more starter bars...
  13. BacBac

    Strut-Tie - Tie Development at Nodes (Starter Bars)

    @bugbus: Agree with you. Does this mean that there'll be a case where you have more starter bars than your actual vertical reinforcement? A coworker has suggested to always have double starter bars for this situation (assuming starter bars only developed by 50% at the nodes), but I don't think...
  14. BacBac

    Strut-Tie - Tie Development at Nodes (Starter Bars)

    Reviving this thread: https://www.eng-tips.com/threads/strut-and-tie-tie-development-at-nodes.513462/ Does anyone have any ideas on how to justify the starter bars reinforcement is developed at the node? For the shear ties, reference from Australian Standards, it's said to be fully anchored if...

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