Concrete Expansion Joint Repair

[structuralnuke]

I have a concrete expansion joint between a electrical manhole and a buried concrete duct bank. The joint is 3" wide by 1' deep and is located below the water table. My problem is the waterstop (sealant) has degraded and only the styrofoam filler is acting to prevent water infiltration and water is flowing into the manhole.

Anyone have a recommendation as to any repair methods? The sealant MUST be a flexible sealant for seismic and differential settlement reasons.

My initial plan was to excavate about 3" of the styrofoam, pack an oakum rope saturated in a urethane grout (product not determined) into gap, then drill holes in rope and inject grout into joint. Any ideas would be greatly appreciated!

 

[JedClampett]

Didn't you like my answer in the Concrete Engineering forum?

 

[structuralnuke]

Yes i'm detailing it now. I duplicated post before your reply; i did so after looking at the lack of daily activity on the concrete board as opposed to this forum. Thanks alot for the help!