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...
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...
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...
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...
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?
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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.
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.
