Jointless abutment details for long curved bridges?

[MIKE_311]

Does anyone here have any experience using a jointless abutment on a long, curved bridge? The structures im looking at exceed 400' and one is over 800' long.

These lengths, plus the fact that they are curved, exclude the use of integral or semi-integral abutments, Deck extensions are also out as they tend to be limited for curved structures at the 300' range.

VDOT has their Virginia abutments that places a the joint and a drainage trough behind an end diaphragm and in front of the backwall that supports the approach slab. They allow these for curved structure that exceed 300' and expansion lengths length than 1.5".

This is the only detail I have seen that would make a bridge "jointless" for a curved structure. They require periodic maintenance and present constructability challenges.

 

[bridgebuster]

MIKE 311. I apologize fr the late reply. That's a very comprehensive example you posted, thank you.

The bridge doesn't require a design exception. NYSDOT permits an empirical stem design up to 20' tall and skews less than 45-degress. I'm still a little leary with a 17' stem and the orientation of the piles. Too late to change things 80% plans are due later this month.

 

[BridgeSmith]

The bridge doesn't require a design exception. NYSDOT permits an empirical stem design up to 20' tall and skews less than 45-degress. I'm still a little leary with a 17' stem and the orientation of the piles. Too late to change things 80% plans are due later this month.

The moments are actually worse on a shorter wall, since the bending on the wall is an induced load. There's less deformation on a taller wall, although, short of a FEA, I couldn't find a good way to estimate the bending moments for the one I did, so I just used the plastic moment capacity of the piles as my design moment.

Rod Smith, P.E., The artist formerly known as HotRod10

 

[MIKE_311]

Its early on a Friday and coffee hasn't kicked in but how are you getting a 17' tall stem design to work without battered piles?

 

[BridgeSmith]

Mike, if the soil pressure on the backwall is limited or eliminated (with MSE, etc.) it can can be done with a single row of vertical piles.

Rod Smith, P.E., The artist formerly known as HotRod10

 

[MIKE_311]

Ok, so it's being actively addressed. Thanks!

 

[bridgebuster]

It's an empirical design, which can be used for an overall height of 20' and skews less than 45-degrees. The 17' for this bridge includes a 5' backwall. I'm still leary because of the skew; the piles are strong axis in the direction of the bridge; I think it will twist. I'm also concerned that one end of the bridge is unbuildable as shown in the plans. The new bridge replaces a longer bridge on the same alignment; work done in stages. I see a number of constructability issues. Of course, I can't argue with not one but two PhDs. What do I know? I only spent 1/3 of my career on the field end of things, which is more years than they have been designing things.

 

[BridgeSmith]

I think it will twist.

It will move in the direction of least overall resistance. If that's the weak axis of the piles, that's where it'll go. We found that out the hard way; it made a mess of the approach slabs, the corbels they rested on, and the slope paving in front of the abutment.

Rod Smith, P.E., The artist formerly known as HotRod10