large baseplate crossing joint

[londonkid]

HI, I have a situation where there is an existing piled foundation. A large baseplate (part of frame of a rectangular steel tank) will sit on a new found adjacent. However due to constraints part of the base will have to sit over the existing found. Therefore the 'baseplate' will sit over the joint between the two.
HOw would you resolve this? My thoughts are, connent in with dowel bars (lots of) to try and create a situation akin to a normal construction joint.
Or Cut out the part of the existing that will carry the load and re cast as one base with the new(will require re analysis of the existing as it still in original use).
Any other ideas? We cannot move the new proposed from its position that is proposed due to other constraints.

 

[BAretired]

I like your idea. Chip out a foot or so of the existing pile...install new pile to same elevation...pour new combined pile cap.

BA

 

[londonkid]

only problem is that it is 2.9m thick slab. so do able but not easy.

 

[Lion06]

Is the new, adjacent foundation a pile or a spread ftg?

 

[londonkid]

piled, both piled. new will be approx 2m deep

 

[Lion06]

The pile is 2m deep or the cap is 2m deep? What is the size of the existing cap? How many piles are j. The group
with the existing cap?

 

[BAretired]

2m seems like a very shallow pile. What is the expected depth of frost penetration? Are the existing piles also 2m?

BA

 

[londonkid]

2m is slab thickness, piles around 15-20m.

 

[Lion06]

I would just drill and dowel into the existing cap. I'm guessing they would have a fairly hard selectively demo'ing a 2 m thick cap to some specified distance over the existing pile and then you're probably going to reduce the punching shear capacity of the existing cap. I'm assuming the new pile is going to be placed very close to the existing? Are the steel piles, micro-piles, caissons?

 

[londonkid]

steel cased piles

 

[hokie66]

I wouldn't be cutting into the existing slab. Expose the edge and tie the new to the old.