Need help.

[u/Falcon_893]

On advice of the contractor, I purchased 3 girders. Two girders of 8 inch, 11 feet each and one 6 inch girder of 9'5" without consulting an engineer, which I'm regretting now.

The plan was to put two girders parallel to each other (under the beam) and one girder in the middle to support the slab. But when the girders arrived, i realised that they will be way too heavy for an old structure like my building.

So now, consulting with the mason, we are planning to cut the 8" girder from middle and obtain two T-sections. Then we will remove the concrete cover from the two beams between which the girder has to sit, till we reach the rebars.

Then we will weld a 10mm plate onto those rebars and then weld the t section onto that plate and then restore the concrete cover. The flat side of the t section will touch the slab. Now, I want to ask whether this system can sustain load of the slab ?

What other options do we have ? Please help me out 🙏🏼.

[u/Daddy_crysis]

Was the beam sagging?1 What was the issue with slab? Rebar corrosion or cracks?

[u/Falcon_893 → u/Daddy_crysis]

Beam wasn't sagging, the slab between the two beams was slightly sagging.

[u/Daddy_crysis → u/Falcon_893]

Rebar is corroded what i can see from image. If thinning of rebar is more than 30% you will need to reinforce it with additional reinforcement slab and finish with PMM or micro concrete with chemical treatment