Concrete sealers & WWM for plaza concrete sidewalks

[smitty9898]

I'm working on a small project where we are replacing a portion of the concrete sidewalk on top of a below grade parking garage. Basically the below grade parking garage extends beyond the face of the building. The concrete sidewalk is bearing on the structural concrete deck. I have two questions regarding the design of the sidewalk:

1. Is welded wire mesh recommended or required for a concrete sidewalk located on top of a structural slab? The existing sidewalk has no reinforcing. I understand there are minimum reinforcement areas required per ACI.

2. Are concrete sealers typically installed on and exterior commercial concrete sidewalk?

 

[JAE]

The structural concrete slab that spans over the void below would have to follow the ACI min. reinforcement AND have to be designed for the required loading from above. This would include its self-weight, the weight of the sidewalk (topping) slab and a live load requirement. Usually this is 250 psf.

In older structures, there would be a waterproof membrane of some kind placed over the structural slab which would be flashed out beyond the edge of the exterior basement wall so any water coming down through the sidewalk slab would be directed out toward the street.

Another waterproofing method would be to cast a single structural slab and over-top with a traffic bearing waterproofing - such as Pedagard by Neogard (

http://www.neogard.com)

There are other similar products out there as well.

A topping slab only needs reinforcement to keep cracking tight. Otherwise not necessary. You can, with lots of control joints, not use any reinforcement in the sidewalk topping slabs.

Sealers can be considered - but they soon wear out and don't really protect the structural slab below from water/chlorides, etc.