Parking Garage Dbl Tee/T Beam Joint Leaking

[BubbaJ]

I have a small 2 level parking garage (1975 vintage) that has a leaking problem (go figure), one level is slab on grade (access via the alley), the other is elevated and accessed via the street. Dimensions are approximately 200'x118' two spans of 24" double tees slope to the center of the garage where they bear on a cast inverted T beam. The joint above the beam leaks like a sieve. There drains along its length, but only on the south side of the joint. Water ponding is a problem on both sides of the joint. It's been repaired twice. We are in a freeze-thaw environment and there is damage to the tee bearing and T beam spalling (maintenance was deferred for many years). Historically, repairs have not performed well. Concrete testing was done on the beam, no elevated levels of chlorides or carbonation (no "smoking gun"). Rebar has shown little corrosion when exposed during repairs. Does anyone have resources for a detail to seal this joint? A repair contractor suggested removing the 3" topping slab above the joint and installing a roofing membrane. Any other thoughts on the situation? Something I am overlooking? TIA

 

[hokie66]

Without a membrane, I fail to understand why this type deck would not leak.

 

[BubbaJ]

The is a traffic coating. It was completely replaced in 2014 and repaired just about every year for the next 4 years. The double tee joints do not leak.

 

[hokie66]

A coating is not a membrane. Perhaps you can provide a section through the leaking joint.

 

[Enable]

hokie66: Your confusion might be due to a difference in terminology. In North America, traffic coating / traffic topping commonly refers to a thin applied waterproofing coating such as MasterSeal 2500. I assume this is what the OP is referring to when they say traffic coating (the entire system of basecoat + topcoat).

BubbaJ: Can you sketch the joint configuration for us? The issue will be with the detailing but without a schematic of the configuration it's hard for me to get an exact sense of the joint. Also, you should contact the coating manufacturer and have them visit the site; since it was replaced in 2014 I would assume the manufacturer is known and still around. Their technical reps should come to site for free to offer guidance on the joint.

 

[BubbaJ]

I thought I had uploaded the detail, apparently not.

There is a 3" topping slab.

Thank you for the tip, I will try getting in touch with the traffic coating manufacturer.

 

[Enable]

If the traffic coating isn't particularly susceptible to wear at above the joint (e.g. turning radius) then you're most likely looking at issues with the detailing. In this case you mention a nearby trench drain. Is the trench drain properly coated with termination reglets at the angle upturn? Any signs of wear at any edges?

If the trench drains seem okay then you may actually have an issue further afield. The fact that structure slopes to this area means that any infiltration is apt to find its way to the ledge. I've sometimes had "leaking" ledge beams where the source of water was some hundred plus feet away.

 

[JedClampett]

I've been in parking garages with gutter systems below the joints. It's not elegant, but it works.

 

[BubbaJ]

In this case you mention a nearby trench drain.

I apologize, I see my original post was worded poorly. There are isolated round drains at 24' O.C. that are offset from the south side of the beam. The repair over the beam prevents some of the water from the north getting to the drain. And you can see, some of the water on the south side doesn't make it to the drain either. There is no cross-slope.

Potential solution:

Remove 6' or so of topping slab at the beam, install a premanufactured joint above the beam in the crown of the new concrete. Add drains to the north side of the beam.

Install permanent shoring and defer the repair of the Tee stems at the beam bearing.