AS3600-2009

[demayeng]

Hi,

This is actually from previous versions of the code also, however Cl 8.1.10.4 (b) says that 1/4 of the midspan positive reo "shall continue past the near face of the support"

How come there is no distance prescribed? what does this mean? does 0.1mm past the face comply?

Thanks

 

[apsix]

The commentary AS3600 Supp1-1994 shows the requirements in figure C8.1.8.5

It just shows the bars extending 'a bit' past the face, no dimension given.

I would use 50mm min.

 

[hokie66]

Note that provision only applies if you are using the simplified method of Cl 6.10. Even if doing the analysis that way, I think the anchorage provisions of 8.1.10.4 should be complied with.

 

[demayeng]

Thanks,

I guess it just needs enough that the closest shear tie has some anchorage

 

[rapt]

demayeng,

That is a minimum requirement. If you have any condition like support settlement or large load reversals or if it is a roof slab with temperature differentials, basically anything that might put stress in the bottom near the support, I would lap the bars at the bottom! Doesn't cost much is is a lot safer.

Hokie66,

I disagree that this applies only if 6.10 is used!

 

[hokie66]

Right you are, rapt. I had 8.1.10.4 and 8.1.10.6 confused. They are a bit different, but I don't know why.

 

[rapt]

hokie66,

8.1.10.4 must be satisfied for all designs.

8.1.10.6 is the minimum deemed to comply bar termination rules to be used where you do not actually do a full analysis and determine bending moment diagrams, points of contraflexure, etc and are therefore unable to calculate real termination requirements. ie when you use 6.10 to determine maximum -ve and +ve design bending moments.

But as I said, I would always at least provide a nominal lap on bottom bars, but that may be because of my PT experience.