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  1. BentEng

    AS 3600 Cl 10.8 Transmission of Axial Force through floor systems

    My thoughts are that you're grasping at straws to justify k=0.7, when it clearly can't be achieved. I suspect you have a calculation error in your gamma factors. The figure is approximate - so is the stiffness calculation. You have no idea what the true stiffness of the slab/column/footing is...
  2. BentEng

    AS 3600 Cl 10.8 Transmission of Axial Force through floor systems

    You have made a mistake with you effective length gamma factors. Look at figure 10.5.3(A). 0.7 is fixed fixed. You can't achieve that with a pad footing, and a slab on one end can't provide equivalent stiffness of two fixed ends. At best you can achieve 0.85, probably higher with a rotating...
  3. BentEng

    Slab to jumpform wall connection

    rscassar - Yes I prefer rebox/pull out bars, but we are getting push back more and more these days on specifying them. Trenno - the stair and landing will be pour later, but with this arrangement, the lobby slab will be poured with the main slab, so sleeved bars would be anchored on both sides...
  4. BentEng

    Slab to jumpform wall connection

    If you have a continuously poured, jumpformed concrete wall, what are the best ways to then connect a slab into the wall? Specifically looking for options where the slab is on both sides of the wall. The wall is 250thk and the slabs are 200thk. Typically our firm specifies Ancon keybox, or...
  5. BentEng

    Etabs pier label results and response spectra analysis

    Hi everyone Can etabs pier labels be used for response spectrum results, where the +be/-ve sign is lost in the SRSS? Can the pier labels adequately convert the absolute resulted at each end of a wall into tension compression resultants?
  6. BentEng

    AS3600-2018 CL14.6.7 hooked horizontal lap bars

    To me "central two thirds" is a confusing way of saying dividing a wall into 4 sections, but thanks for the clarification. Unfortunately I've seen other firms use this interpretation to get away from the detailing. I assume that a wall goes beyond the elastic limit is more likely to have cover...
  7. BentEng

    AS3600-2018 CL14.6.7 hooked horizontal lap bars

    Hi all, Looking at the CL 14.6.7 requirement for "all horizontal lapped bars within the central two-thirds region of the wall shall be provided with minimum 135degree hooks and lapped with a full-strength splice (figure 14.6.7(D). 1. What is the central two-thirds region? Is this meant to be...
  8. BentEng

    Post-tensioned beam reinforcement detailing AS3600

    Hi rapt, I don't mean for this to be a complex theoretical discussion, merely an interpretation of the detailing rules for beams and slabs, specifically the % of positive moment tensile reinforcement required to extend beyond the face of the support. I've said beams because this is the example...
  9. BentEng

    Post-tensioned beam reinforcement detailing AS3600

    It's definitely vague, especially when there's a conventional reinforcement diagram in section 9, but nothing for PT. I've seen dozens and dozens of buildings with PT slabs and no btm Reo, so I would think that it's almost a universal understanding that the tendons are applicable to the clause...
  10. BentEng

    Post-tensioned beam reinforcement detailing AS3600

    Hi CL 8.3.1.3 of AS3600 (2018, used to be CL 8.1.10.4), gives minimums of the quantity of positive moment tensile reinforcement required at midspan to be extended beyond the face of the support. 50% at a simple support, 25% at a continuous. Do PT strands count towards this, even as they drape...
  11. BentEng

    Flexural behaviour of walls as a function of design approach

    Hi RAPT I suppose this is a more theoretical question about how the wall would behave if you designed one way or the other. I understand that the 2018 3600 states explicitly that walls are to be designed as per option 2, if detailed for ductility. In this case, I believe it's to avoid...
  12. BentEng

    Flexural behaviour of walls as a function of design approach

    Hi I'm wondering what the difference is in wall flexural behaviour, stiffness, neutral axis depth etc if I design a lateral resisting wall in the following ways (AS3600), considering axial and moment loading: 1. Cracked section analysis using an equivalent stress block and lumped end tension...
  13. BentEng

    Compression element slenderness AS3600

    RAPT, When you say eurocode method, to clarify, are you referring to the nominal curvature method?
  14. BentEng

    Compression element slenderness AS3600

    RAPT, In your opinion (maybe you can't say) is the eurocode method the best/(most accurate) for slender RC columns/compression elements? It sounds like AS3600 CL11 might be unconservative but CL10 moment magnifier might be too conservative..? I've had a look at BS8110 (which I believe is...
  15. BentEng

    Compression element slenderness AS3600

    Hi I know this topic has been beat around a bit before on here but with the new AS3600 I was hoping there would be some clarification regarding Wall v Column design, namely slenderness and second order bending effects, moment magnifier etc. Without going into seismic and ductility, lightly...
  16. BentEng

    Punching shear v Beam shear capacity comparison

    Hi, I have always been under the impression that the AS3600 punching shear equations would be more conservative than the beam shear equations. However recently I have found this isn't the case (?). CL9.2 merely calculates a concrete shear stress, then applies that to the shear perimeter for...
  17. BentEng

    AS3600 2017 Draft

    I was hoping this clause would potentially help clarify when it is/isn't appropriate to use chapter 11, however if it does only place the new limitations on singly reinforced "walls" then I guess the ambiguity will remain, and we'll continue to see blade columns designed as walls in multi-level...
  18. BentEng

    AS3600 2017 Draft

    Are you suggesting that this might not make it into the final code? If anything, I think that makes it even more worth wondering about, and important to discuss, regardless if the next drafting is released or not.
  19. BentEng

    AS3600 2017 Draft

    Any thoughts on the new restrictions placed on the use of the simplified wall capacity method? I know plenty of buildings over 12m tall using this clause to design blade columns.
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