If the bridge is fine, there is no problem.

If the bridge is rotten, you have lot fewer victims.

You want to do pre-emptive repairs? OK, the bridge ought to be fine. We can then proceed with the destructive testing.

You could do the testing with something like 110% of the typical max traffic load. A rotten bridge would then collapse within 6 months of it's "natural collapse". Only things you do is to make the collapse more predictable and you save lives.