Purpose
A diagnostic load test provides measured evidence of bridge behaviour under controlled loading. The objective is to compare observed strains, deflections and transverse load distribution with analytical expectations and reduce uncertainty in structural evaluation.
Planning considerations
- Define the engineering questions and acceptance criteria before testing.
- Select truck configurations, lane positions and load cases that activate the governing structural responses.
- Develop instrumentation and data-acquisition plans for strain, deflection, displacement and temperature.
- Coordinate traffic control, access, safety and test sequencing.
Interpretation
Measured results should be reviewed for repeatability, linearity, elastic recovery and consistency with the analytical model. Diagnostic testing does not replace structural evaluation; it strengthens the evidence base used for rehabilitation, load-rating and asset-management decisions.