Construction Joint Testing 1

[StructSEZ]

Hi,
I have a situation here where concrete was poured in a manner that created an 'unplanned' construction joint (in a suspended beam/panel slab).
Part of it runs over a wall support and I want to ascertain the quality of that joint in terms of the bonding and concrete strength through the joint (which is inclined at about 45 degrees) in that area.
I'm thinking of taking some cores for visual inspection and load capacity assesment.
My question is, are there any standards or literature out there which might guide on what to look for and maybe even some testing methods?

Thanks,

 

[ishvaaag]

Basically I would explore the ability of what built to pass the stresses to one side and the other side of the interface for a range of friction factors in some kind of friction shear scheme.

I think it would be a truly bad joint the one that unable to behave reasonably upon monolithic concrete if well reinforced; in fact, some kind of deteriorated joint, a crashable, able to freely open or greased one, typically. For most other situation ever a poorly executed cold joint should behave at service level in quite akin form to monolithic.

Another focus of attention is that water won't be able to access the rebar through the joint.

http://ieeexplore.ieee.org/Xplore/l...0991834.pdf?arnumber=991834&authDecision=-203

 

[StructSEZ]

Thanks for the reply.
I see what you mean regarding the friction mechanism as a method of stress transmission. I'll do some numbers on that. I believe the friction co-efficient of concrete generally floats around 0.33.

I'll also include a range adhesion values to model the non-mechanical bonding along the joint.

Thanks for the link as well, I'll definitely have a read of that paper.

 

[ron9876]

I would recommend not pouring new concrete over a 45 degree slope on the old concrete. I would cut it vertical, check shear stresses, add shear friction steel if required and continue the pour.

I am a little fuzzy about what you mean about part of it over a wall but when you are done the stresses have to work for the proposed condition and the surfaces should be vertical, clean and sound.

 

[StructSEZ]

Ron,

Thanks for the reply.

With regards to the wall, I meant that there's a shear wall underneath which is also supporting the slab.

Just out of interest though, what is 'friction steel'?