@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...
@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...
@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...
@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?
@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...
@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...
@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...
@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...
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...
Ingenuity:
Thanks.
Yea, double live-end is not typically done anymore, and again it's due to safety issues.
We typically have 2 tendons stressed from each side and have it lapped.
Can't deny that we're not the best. [upsidedown]
hokie66:
Thanks for the comments. The previous snapshot is from a...
Ingenuity
True, in that particular snapshot, the construction joint is a "pour joint" as the builder cannot pour the whole slab in 1 pour. Some people call these bars as "stitching bars"
Typical detail is as per snapshot below.
Did you mean intermediate coupling anchorages for the tendons?
I...
hokie66:
There's top and btm bars continuous through the construction joint to maintain moment continuity.
I believe the props would stay until both pour reaches its strength.
Retrograde:
Apologies for my bad wording. Not meant to have tendons pass through the CJ as it'll start-stop.
The...
Thanks all for the insight. It's been very useful.
Ingenuity:
I agree with you. I'd avoid pans whenever possible due to the extra reinforcement, extra loss, potential congestion, possible clash with other reinforcement/pans, etc. which leads me to asking this question to know when...
Hi All,
Structural engineer from Australia here.
I have 2 questions regarding detailing a post-tensioned slab for its anchorage type (edge stressing vs pan stressing).
Q1. Does anyone know when edge stressing may be rejected by architect or builder?
Besides the obvious reasons such as edge of...
Hi Tomfh,
This is a concept question that kinds of applicable to all cases.
Basically, it's to compensate that at the nodal zone, you aren't able to develop 100% (500MPa yield stress for Australia N Bars) of the anchorage of the wall vertical bars (see snapshot below), hence you put more bars...
Hi JAE,
Thanks for your insight.
As per the Australian Code (See excerpt from the code commentary on the image below), exactly at the end of the cogged/hooked bars, it's generally taken as only 50% developed.
i.e. in my figure 2, exactly at the node location, the bars are only developed by 50%...
https://res.cloudinary.com/engineering-com/image/upload/v1723617656/tips/Core_Wall_Starter_Bars_1_degmkq.pdf
Hi All,
I'm a structural engineer working in a consulting firm in Australia.
There's a new manager in the company whom I'm working under at the moment, and he insisted that we should...