Assuming you can make a temporary access opening through the deck, consider this idea. Sawcut a deck opening about 3 ft by 4 ft (long dimension across the deck). Perform your inspection. After inspection is complete, close the opening with a concrete plug.
To make the plug, first bush-hammer the saw cut surface to increase aggregate bonding. Drill horizontal dowels into the existing deck and grout with epoxy. Be generous with length of dowel to help compensate for unknowns. Space the dowels about the same as the existing rebar. Avoid cutting any rebar already captured in the deck as much as possible.
Make a frame out of 4 in x 6 in angles (or 6 in x 8 in if you like) thru-bolted to the underside of the deck with the long leg vertical. The bolt holes should be at least the deck thickness away from the saw cut opening. For the form use two layers of ¾ in plywood cut large enough to overlap the opening about 6 inches all around. Support the plywood with angles bolted to the 6 in vertical leg, say every 12 in spacing, using simple angle bracket connections. No welding needed. The plywood does not have to be in one piece as long as the joints are over a support angle.
Complete the reinforcing for the new plug pour by tying onto the dowels. Consider some kind of bonding agent applied to the raw deck concrete edge, then place a mix that is comparable to the existing deck mix, including aggregate size and hardness. The plug concrete should wear at the same rate as the existing surface. Low slump low shrinkage would be best, but cure time would also be a factor if traffic disruption is involved. Vibrate the pour, but not too much.
When sufficient strength develops strip the forms from below, passing the angle pieces and other hardware out though the access opening. The plywood can be cut into smaller pieces with a battery powered saw if they are too big for the opening. Remove the bolts and plug the bolt holes in the deck.
Sweep up, pack up, send an invoice to the owner, go home and have a beer.
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Norman Voigt P.E., P.L.S., F.ASCE
Retired
Pittsburgh PA
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Original Message:
Sent: 04-30-2018 14:51
From: Brian Grom
Subject: Tub Girder Deck Panels
This is a one-off requirement that we have never seen and the DOT is not even entertaining options outside of being able to inspect the completed bridge deck from inside the tub girder with no lost deck forms in place. The forms must be removed, anything in place not an option. With our limited options to access and strip, and trying to minimize gaps in the deck to remove all the deck form material, I'm looking for ideas on efficient ways to form and strip our closure pours to complete the deck.
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Brian Grom A.M.ASCE
Project Manager
Hilbert WI
Original Message:
Sent: 04-27-2018 08:15
From: Adam Shelton
Subject: Tub Girder Deck Panels
With that long of a span, I would assume the tub girders are big enough that you could inspect the entire deck from within the girders. I never heard of removing decking to inspect a bridge in my few years as a bridge inspector, but I guess there are always special circumstances.
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Adam Shelton P.E., M.ASCE
PROJECT MANAGER
Suwanee GA
Original Message:
Sent: 04-26-2018 09:03
From: Brian Grom
Subject: Tub Girder Deck Panels
I have a unique scenario on a tub girder bridge deck, the decking material must be removed for inspection of the deck from inside of the tub girders. The access to the tub girders are small hatches (less than 3'x2') at either end of a 1200' total span. Gaps in the deck to remove materials is being explored but at some point there will be closure pours on the deck. I am looking for suggestions and even fabricators that have ideas on prefabricated small sized deck forms that can be easily installed and removed and fit through our access.
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Brian Grom A.M.ASCE
Project Manager
WI
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