Use of Self Consolidating concrete at PT anchorages 1

[jimaitken]

We designed a post-tensioned integral bent cap for a highway bridge. The beams are steel plate girders and the PT system is Dywidag bars. The anchorages are on the outside face of the beam webs and the plans call for the anchorages to be encased in concrete by forming the bent cap end over the anchorages and fully encasing the plate girder from top flange to bottom flange.

The contractor has contacted me to ask if there is another way to build the end of the bent cap. The cap end is moderately reinforced and is a very tight space to place concrete. The dimensions of the cap end are 7'deep x 9'-6" wide and 10" thick( 1/2 the flange width). Access is restricted by the bridge deck overhang. He does not think this can be done using regular placement methods without the posibilty of voids and segregation of the concrete and I agree with him. I would think that a self-consolidation concrete would work well in this case but I have no experience with it. Are there other alternatives? Shotcrete? ??

I would appreciate your suggestions.

Thanks.
Jim

 

[civilperson]

Closed form with threaded bottom entry, pump super plasticized small aggregate mix, (f'c.> 5500psi)into the bottom of the form until it appears in the the top relief tube.

 

[jimaitken]

I like the idea. I'll run it by the contractor and see if he is open to it. Thanks.