If it needs to be repaired, the materials needed are: steel bar, concrete, formwork and supporting scaffolding.
Clean up the steel bar first, and then support the scaffold installation template.
Treat concrete joints according to the method of construction joints.
Cement mortar and loose layer on the surface of poured concrete should be chiseled away, and then a layer of cement slurry should be brushed on the surface of old concrete.
Then a higher grade of concrete should be poured.
It is better to find the original design unit to make a modification plan, which is not easy to construct without authorization.