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Recent content by omegaeng

  1. omegaeng

    Tower raft - 100% bearing, no piles

    winelandv - for clarify, which was the similar approach you saw? I think you were talking to my second post (designing it as a massive column)? And then how would you get your reinforcement - strut and tie? I'm no geotech engineer, but I didn't know that soil can redistribute forces. Concrete...
  2. omegaeng

    Tower raft - 100% bearing, no piles

    Thanks for your response. He did a variation of your Model 1, but only did one "strip" (a strip about the heaviest loaded wall). But I still don't get the logic. Can you think of any other ways to simplify it - say, using just the heaviest wall? Someone else just suggested that it can be...
  3. omegaeng

    Tower raft - 100% bearing, no piles

    Hi, So I'm reviewing a raft design for another firm and I don't see the logic in their design approach. I was hoping that someone could tell me what they thought of the design approach and maybe, how they would have designed it. Design brief: 30 story tower, 100% bearing raft (no piles) Core...
  4. omegaeng

    Piled raft design - S&T or flexure

    Good point about all those load cases! I'm still trying to establish a technical and full-proof reason why we can design deep rafts using flexure, in spite of the code clearly stating that we should be using a strut and tie approach. Regarding checking the highly stressed walls for s&t - I...
  5. omegaeng

    Piled raft design - S&T or flexure

    You're right - in the permanent condition (full building weight on piled-raft), you'll get some sort of "dishing" effect of the raft (deformed shape), so you won't get any moment or shear reversal. But this is only true if you've modelled your piles as springs and not supports. You might get...
  6. omegaeng

    Piled raft design - S&T or flexure

    The one I'm doing now is for a fairly slender tower - approximately 30m x 30m of raft under the tower. But the last one I did was something like 90m x 120m - this was for two towers plus a common basement car-park between the towers. Both were rafts about 2000mm deep. Why wouldn't the span be...
  7. omegaeng

    Piled raft design - S&T or flexure

    In every company I've worked for, in any country, complicated piled-rafts (complex pile, column over and wall over arrangements) have been modelled in FE software. (This too goes for complex/large/irregular pile caps.) The piled-rafts I've designed have all been very deep, ranging from 2m to...

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