@sammydog01 I think you would have to be asking about a specific ancient bridge… Then it would be a guestimate from an expert based on the size of the peir, the depth, the material you’d remove. Then you have to get an average work measure. And if it’s all men. If there are women. Kids.
Then how many you threw at it…if there were slaves.
Time in a construction project especially an accient one that is not documented who knows