You are right. But I fail to see what K1Ac has to do with dowel action, although it is not specific to it. It seems to me that K1Ac is for cohesion only.
@le99, your first image is how I understand dowel action, which means the shear resistance should have dowel bar flexural & shear capacity...
Also, it says "These values of K1 apply to both monolithically cast concrete and to concrete cast against hardened concrete with a rough surface, as defined in 11.6.9."
I wonder why dowel action has to do with the roughness of interface?
I believe shear friction and dowel action are two different things. (I am not talking about the shear friction here). My point being dowel action should have to do with the flexural & shear capacity of dowel bars, not just concrete compression, as is expressed AcK1 in the above expression.
In ACI 318-11 commentary, I have found the following in regard to dowel action in shear transfer, which is removed from ACI 318-19, in addition to shear friction.
However, I am not getting why dowel action is expressed as AcK1 which has nothing to do with dowel bars? (I don't have reference...
Yes it is. Walls are in-situ tho. Also, I don't think precast walls means pin connection especially in plane? The dowel bar will still give you moment to transfer.
The uncracked walls & slabs model from the very first picture is a simplified 2D model without considering construction sequences.
When you design your slab in this way, do you take the axial load of walls above from staged construction sequence?
If so, is it really safe to ignore the moment...
I did have run a 3D model analysis with staged construction sequence as I mentioned. It does reduce the moment but in some case the moment is still large.
Yes reducing the stiffness of walls alone will reduce the moment but what if we crack the wall & slab at the same time? The moment might...
It is a non-seismic zone. I can pin the column in the analysis but my concern is that in real world it will not follow this assumption - there will be moment at the ends of the columns. Can we ignore this moment and why?
Just to clarify that using vierendeel truss to design the transfer slab is...
The out-of-plane thickness is 200mm. I guess you can call a 200x1000mm either wall or column. But even if I reduce the wall to 200x600 the moment is still quite large
Below is a section of the transfer structure I am working on. The transfer slab is going to be 400mm PT.
I am getting large moment at the bottom of internal transferring walls as you can see from the picture below.
Above is a 2D model but I have created a full 3D model and considered the...
I am still a bit confused.
I have this from CSI website where it says "Walls are generally not designed for out-of-plane bending to avoid excessive longitudinal reinforcement. In this case, use a small modifier say 0.1 for m11, m22 and m12 so numerical instabilities could be avoided. "...
Thanks everyone.
@centondollar What I tried to say by "statically determinate" is that say a simply support beam, there is no moment distribution involved.
A bit off topic but I am wondering do you reduce your out-of-plane stiffness of RC walls that connect to RC slabs to say 0.1 or even less...
Understand the total of WL2/8 as a whole will not change. I guess what I tried to say what I initiated this was, say use your example, I have different reinforcement for span and ends and if I design to the elastic case with ql^2/24 for my design positive moment, and when it cracks over the...
Okay thanks.
If I am not mistaken, as long as the beam doesn't become statically determinate (ie not hinge generated at supports) we don't need to consider moment redistribution for positive moment because once it exceeds the MCr+ it will redistribute back to elsewhere?
Given that for continuous concrete beams the moment generated at the supports will normally exceed the cracking moment Mcr of the beam, isn't it a must to increase the design bending moment & corresponding reinforcement at mid spans generated from a elastic frame analysis?
Can anyone please...
Thanks everyone.
I just got the Guide that Retrograde mentioned where it says "Typically, 600 mm is a comfortable minimum width for legs and mullions, while 900 mm is a comfortable minimum depth for spandrels". But I failed to find the reasons behind 600mm & 900mm. I would argue that 600mm as...
@Trenno, some are single story warehouses some are multi-storey buildings. Is there any reason behind 4x? I know the only thing for 4x is fire but do I need to design this leg to fire as column? And even if I design it as column to fire, in many case it will still pass when the axial force is...
Is there any limit for the length of the precast panel legs next to opening? I have seen some people specify 600mm while some make it 300mm despite that their loads are quite close. I would argue that as long as the N-M satisfies (ligs provided if required) and there is no problem for...
I tried 200x100 rectangular hollow section to reduce the deflection to 20mm but am just wondering if changing the layout would be a better idea instead of changing the section or size just to pass defection check?
Thanks for the quick response SRL V1.0.
Yes I called it struct because they are structs for the other orthogonal direction wind. In the middle I would just use double purlins. I am not worry about the wind coming in this directions.
It is the wind coming the direction as shown the plan that...
