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Recent content by rapt

  1. rapt

    Integrity Steel Interpretation

    The sentence in the code above the equation explains it. The sum on all faces of the column. You should ask for your money back on the text book. ACI code works differently and might result in something like the textbook.
  2. rapt

    Minimum Flexural Reinforcement ACI 318-19 8.6.1.1 for a very thick slab

    JoshPlum, The 4/3 rule for beams is the anomaly and is not in any other code that I know of. It was in older Australian codes but was removed in 1988. It is not logical in limiting ductility. If you are trying to ensure ductility, the tension strain in the reinforcement is the problem. But for...
  3. rapt

    Flexural Steel in Beam ACI 318-19(22) 9.6.1.3

    It is a very illogical concession. If you do the calculations by strain compatibility and check the strain in the reinforcement against the breaking strain, you will find that reducing the minimum with this rule will often result in the actual steel strain being significantly higher than...
  4. rapt

    Structural theory behind Design Strips in two-way slabs (as per CSI-SAFE)

    It is not practical to design for a varying moment across the width as your reinforcement spacing would be continually varying. Normal allowed logic is to consider 2 strips, column (support) strip and middle strip with the total moment in each strip averaged over the strip. Most codes then have...
  5. rapt

    Determining Moment from different strains of column interaction

    It should be about the plastic centroid, calculated under pure axial. As Smoulder said. The calculation can be about any position, but it should be transferred to the plastic centroid for the final result.
  6. rapt

    Comparison of EC2 and BS8110

    1 EC2 development lengths are not overly conservative. I would use them rather than the old BS8110 values. 2, BS8110 3.12.9 is the equivalent requiring reinforcement to extend D past where it is required. 3 I would never use L/D ratios for deflection. They give sa good starting point...
  7. rapt

    Prestressed Beam Design to ACI

    RAPT fully incorporates ACI-318 for Pre-tensioned beam design as well as Post-tensioned design. www.raptsoftware.com
  8. rapt

    Column Design - concrete - Biaxial bending - Why the r/f area is not deducted from concrete area

    It is still nearly 10% of the steel force. It should not be ignored, especially in heavily reinforced columns.
  9. rapt

    Column Design - concrete - Biaxial bending - Why the r/f area is not deducted from concrete area

    It should be removed, or the reinforcement stress reduced by the stress in the concrete (gives the same result).
  10. rapt

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

    Stirrup bend details are a special case and the code assumes full development for this. If the vertical Ties have a standard hook/cog, that is not equivalent to a stirrup detail and only provides 50% development according to AS3600.
  11. rapt

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

    "What does it mean that development can be assumed to be continuous?" It means you get no benefit from the bend. It is simply based on the length of the bar. RE Development of the tension tie, I think you should read 7.3. You need to develop the strength at the node!
  12. rapt

    Do you think it is right to design it as a 150cmx150cm column and rod element?

    Never used Etabs but I would assume a ROD element is a tension element!
  13. rapt

    Under-reinforced beam

    I disagree with stripping the formwork if the strength under the construction load is ok. It is far better to add strengthening before any deflection has occurred.
  14. rapt

    Partially Developed Reinforcement

    If you limit the bar size, you could ensure the bar can develop yield at the critical section for bending near the inside face of the column. So the maximum bar size would be dependent on the support length. In ASS3600, you would get 50% development from the cog, plus the length to the critical...
  15. rapt

    Partially Developed Reinforcement

    There is a phi factor built into in the bond calculation for reduced capacity of the reinforcement. In Eurocode, which actually provides the basic calculation , converting material factors to equivalent phi, that comes to about 1.15 / 1.5 = .75. This is built into the Australian code development...
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