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...
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...
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.
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...
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.
"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!
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.
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...
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...
Unless you have a heavy point load on the end of the cantilever, why are you worried about S/T modelling anyway? Whatever reinforcement you need at the end column for the internal span would be adequate for the short cantilever.
The main benefit of a corner bar is to reduce the compression stress concrete in the curve of the main bar, thus allowing tighter bend radius.
This is useful for stirrups and other applications where bend radii are a problem in detailing such as corbels.
Eurocode and the FIB Model Code have...
You have simply created a new tension zone at the back of the anchors.
Is there other horizontal reinforcement to transfer that tension force further into the kerb/deck?
The old method was based on Zustti's logic and the perimeter was set at the larger distance to match the method to test results.
The new code uses The Critical Shear Crack Theory developed by Muttoni and has gone back to using .5d for the perimeter, along with limitations on the length of the...
