corroding nosing bars
corroding nosing bars
(OP)
An existing cast in place framed concrete stair I am reviewing has numerous locations where the treads have cracked due to corrosion of nosing bars. Am having probes and tests done but my guess at this point is that lack of cover plus frequent salting have resulted in the nosing bars corroding and then spalling the concrete.
The question is how best to deal with the rebar corrosion long term. The nosing bar corrosion is not really reducing the structural capacity of the stairs, but the client does not want to see rust stains and cracking/spalling anymore. I don't see removing the loose concrete, cleaning the rusting bars and then patching as a complete fix. Additonal cover cannot be added as part of repairs because it will distort the dimensions of the treads. This also appears far too small a job to use csthodic protection.
I am considering just cutting the nosing bars out completely. There is an existing bottom mat of bars (which are in ok condition) each way in the bottom of the 8" thick stair slab, which can be counted on to tie everything together. The stair is about 18' wide.
Has anyone tried removing nosing bars and patching?
The question is how best to deal with the rebar corrosion long term. The nosing bar corrosion is not really reducing the structural capacity of the stairs, but the client does not want to see rust stains and cracking/spalling anymore. I don't see removing the loose concrete, cleaning the rusting bars and then patching as a complete fix. Additonal cover cannot be added as part of repairs because it will distort the dimensions of the treads. This also appears far too small a job to use csthodic protection.
I am considering just cutting the nosing bars out completely. There is an existing bottom mat of bars (which are in ok condition) each way in the bottom of the 8" thick stair slab, which can be counted on to tie everything together. The stair is about 18' wide.
Has anyone tried removing nosing bars and patching?






RE: corroding nosing bars
RE: corroding nosing bars
RE: corroding nosing bars
Pull out the rusting trim, replace it with a fiberglass or plastic trim piece - I've used the safety-reflective edge piece inserts outside on stairs for this when I've made repairs in the past - and set the new trim pieces in the two-part epoxy resins mentioned above. The new trims will seldom exactly fit back in the slots left from the old rusted parts.
RE: corroding nosing bars
The problem here is corroded reinforcement bar, not trim.
RE: corroding nosing bars
Cut them totally out and then patch the concrete.
The epoxy patch will be a much darker color than the original concrete. A cementatious patch will be closer but most likely will be a different gray color but not as far off. You may want to consider applying Thoroseal to the stairs for a uniform color after the repairs are made.
RE: corroding nosing bars
RE: corroding nosing bars
RE: corroding nosing bars
Dik