https://www.youtube.com/watch?v=-pnOXuRI0vM

This guy pushes a bulldozer slightly more than half the length of a soccer field. At the end of this it's stated that his time isn't even close to Captain America's, so this should be a lower-bound for his strength.

The bulldozer looks to be a Caterpillar D9.

Weight - 48,988 kg

Distance - 52.5 meters

Timeframe - 15 seconds

52.5/15 = 3.5 m/s

((48,988 kg)(3.5 m/s^2)/2 = 300.1 kJ

Results

Captain America's Strength (Minimum) - 300,100 J, Wall level

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