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