Deterioration by impact
Impact damage usually causes some concrete to be damaged and lost. Unless there is a serious loss of section the result of impact damage will be some loss of strength that within the range of the original design safety factors lead to failure. However the effect of the loss of section should be investigated by an engineer and with any necessary repair being done as soon as possible.
During this period, temporary structural support may be required and the loading stresses should be reduced by support during repair so that the newly added material can take the same proportion of applied stress as the original material that was lost. In the worst case impact may cause collapse or make a structure unsafe.
An unsafe condition should be carefully, and safely, evaluated so that temporary supports can be introduced or the structure demolished.