Construction methods · Finishing, articulation and maintenance

Load testing, inspection and handover

Before traffic, the bridge is loaded with trucks at known positions and its deflections compared with the analysis; a dynamic test measures frequencies and damping. Together with the inspection of every component and the as-built records, it is the last hold point and the first entry in the maintenance file.

How bridges get built · Finishing, articulation and maintenance · Load testing, inspection and handover

Also called: proof load test, acceptance test, as-built documentation, bridge handover

Load testing, inspection and handover — concept diagram — Concept diagram (TheBridgeEng)

How it is done

Plan the test: loading cases that produce 60-90 % of the design live-load effects; instrument with deflection gauges, strain gauges and accelerometers.
Load in stages with weighed trucks; record and compare; accept when measured deflection is within the predicted range and recovers on unloading.
Complete the principal inspection, the as-built drawings, bearing pre-set records, PT records, cable force records and the maintenance manual; hand over.

Where it fits

All new bridges in many jurisdictions (mandatory in Italy, Spain, Poland, Korea for large bridges); recommended for long spans and unusual structures.

Where it does not

Testing without an analysis to compare against; overloading.

Plant, pace and money

PlantLoaded trucks, instrumentation, survey.

ProductivityOne to three days of testing; weeks of documentation.

CostUSD 50,000-500,000 depending on size; the game's schedule ends with it.

Risks and controls

What goes wrong

Unexpected deflection revealing a construction error; damage from overloading.

Quality assurance

Independent review of test results; complete document set as a condition of handover.

Examples

Every game bridge finishes with the load test segment; Korean special bridges undergo static and dynamic tests before opening.