horizontal construction joint at cip box girder 1

[cjung]

My question is regarding single cell Box Girder Bridge Construction, Horizontal Cold Joints between webs and slabs.

Questions:
The client approved cold joint locations at between bottom/top webs and bottom/top slab, respectively.

1. Does that mean the client approved the visible cold joints at C-I-P Box girder?

2. Are there guidelines explaining about visibility restriction of horizontal cold joints at C-I-P Box girders?

3. I am concerning about the visibility and the contractor says the client approved the visible cold joints at the box because the client approved the cold joints.

4. Is there any way to minimize the visible cold joints?

 

[KootK]

Can you not just ask the client if they are okay with the cold joints?


I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[bridgebuster]

Just how ugly are they? We have several CIP boxes recently constructed with cold joints and no one's complaining about aesthetics. You could try grinding the joints a bit to make them blend in.

 

[cjung]

Thanks Bridgebuster! We are about to pour webs.

May I ask "Bridgebuster" regarding the construction joint preparation you guys did for your boxes?
We utilized the green-cutting(power wash, 3200 psi). Some area turned out to be a great joint with well exposed aggregates, but some area were not fully exposed the aggregates. I told them to re-wash using even higher pressure after a while. I am not sure it will expose aggregates well. Could you please share your experience?

 

[bridgebuster]

cjung, we used a keyed joint. The bottom of the slab was built up at the webs and the key was formed. The surface was left rough. Similarly the top of the web elements were keyed for the top slab. Prior to the concrete placement the keys were sand blasted to clean them up, then wet down.

 

[cjung]

Bridgebuster: may i ask the direction of the keyed joint? Is it perpendicular to the web?

 

[bridgebuster]

Cjung, it's a vertical recess that runs parallel in the direction of the web. I attached a detail of the joint.

 

[rapt]

Have you checked horizontal shear at the joint with a CJ?