More information might help.
I would anticipate that any load testing would be done because it was mandated by some standard or code and that standard or code would also dictate to a fair extent what was to be done and how.

IN WHICH IS THE PROCEDURE TO PROVE THE BRIDGE'S RESISTANCE? THE BRIDGE WAS DESIGNED FOR TRAFFIC OF HEAVY CRUDE TRANSPORT VEHICLES

We constructed an "on" ramp which did not have enough super elevation as the ramp rotated. That discovery was detected after the ramp was completed. Although the heavy structural steel components had been assembled entirely at the fabrication plant and conformed to the design requirements for curvature, elevation etc..., somehow the third party designing firm had made a mistake which was discovered when the ramp was completed with parapets and pavement, railings etc... Nonetheless, the state DOT suggested that we load the ramp with truck cranes for a specified amount of time to detect any further flaws. DOT was satisfy with such a load tests however the life span of the ramp was reduced.

if correct the tests of resistance of the point were made with load depending on the capacity for which the bridge was designed, now the problem that I have is that they ask me to indicate this procedure but in docuemntacion, there is some standard format to elaborate procedures for this kind of structural bridge tests?

This is a most unusual requirement so I'd guess there is no accepted standard. I'd develop a program for the test with the actual loaded vehicles used, but I'd first have sufficient supports under the structure to prevent it from failing, yet sufficient to see that the structure can carry what it is designed for. Measuring deflection of the bridge would be mandatory and the structural engineer is likely to be able to give the deflection limit that would indicate acceptance/failure.

BVRS -- where is the bridge located? Oldestguy is right that there likely is not one standard procedure, but you may be able to work from some of the bridge codes in your region as a starting point.

Why is a load test required instead of an analytical load rating?

The procedure itself will depend on the design of the structure. Find the two or three most likely "weak links" in the design. Then come up with a way to validate their performance using the resources at hand (trucks, concrete barriers, etc).

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The name is a long story -- just call me Lo.

I don't know how sophisticated your testing capabilities are, but I have used the following procedure...

1. Determine the analytical capacity of the bridge
2. Set up strain gauges on the bridge structure at locations that match your analysis points.
3. Set up digital dial indicators at strategic deflection points
4. Monitor all remotely by computer as a heavily loaded truck with known axle weights drives slowly across the bridge with no other traffic on the bridge
5. Do this several times for repeatability
6. Back-check the data obtained against the predictive analysis