Steel reinforcement damaged by mechanical hacking
Steel reinforcement damaged by mechanical hacking
(OP)
Our Contractor at site has damaged existing steel reinforcement while hacking our RC slab in preparation to cast an extension. Was wondering if there are any guidelines out there (or rule-of-thumb) on how much the steel bar can be damaged mechanically by hackers and still be considered 'acceptable'/'safe'. i.e. in terms of loss of cross sectional area or some other measurable criteria.
The steel bars are actually starter bars that were cast in the slab in the previous phase for us to lap with when we extend the structure for the next phase (which is about 5 years in between phases). The steel reinforcement is Grade 500. (i.e. chracteristic yield stress of 500N/mm2)
I'm actually writing from Malaysia, so we usually refer to British Standards / BS-EN on stuff like this, but I couldn't find any guidance on this matter in BS8110. Any input on this matter is greatly appreciated.
Lester Seow.
The steel bars are actually starter bars that were cast in the slab in the previous phase for us to lap with when we extend the structure for the next phase (which is about 5 years in between phases). The steel reinforcement is Grade 500. (i.e. chracteristic yield stress of 500N/mm2)
I'm actually writing from Malaysia, so we usually refer to British Standards / BS-EN on stuff like this, but I couldn't find any guidance on this matter in BS8110. Any input on this matter is greatly appreciated.
Lester Seow.





RE: Steel reinforcement damaged by mechanical hacking
I will usually loook at it from the point of view that if the full bars are required for strength then any deterioration is not accepatable, but if the bars are only partially stressed then it may be okay if it looks like it has sufficient portion of strength left.
You need to use your engineering judgement.
RE: Steel reinforcement damaged by mechanical hacking
RE: Steel reinforcement damaged by mechanical hacking
RE: Steel reinforcement damaged by mechanical hacking
since the concrete will gain strength with age you might just get away with cube tests on the existing concrete to give you a service stress and thus justify a slightly reduced steel area.
RE: Steel reinforcement damaged by mechanical hacking
I would guess that if bars were placed in the last pour to lap with that the load must be transferred into these existing bars. If you epoxy into the slab, that will only develop the bars being epoxied in, it will not develop the existing bars. I think this might be a problem.
I would agree with csd72.
RE: Steel reinforcement damaged by mechanical hacking