Load Testing / Proof Loading
Direct Verification of Structural Capacity Under Controlled Loading
Load testing is the direct method of verifying structural capacity, applying controlled loads to a structure and measuring its response. Where analytical methods calculate capacity from material properties and geometry, load testing demonstrates capacity by applying the actual loads and observing the actual structural behaviour. For existing structures where material properties, connection details, or composite action are uncertain, load testing can provide capacity verification that analysis alone cannot deliver with confidence.
TRSC conducts load tests following a structured protocol: instrumenting the structure with deflection gauges, strain sensors, and crack monitors; applying load incrementally in defined stages; holding each load stage while recording structural response; monitoring for signs of distress (excessive deflection, cracking, non-linear behaviour); and unloading to verify elastic recovery. The test is controlled by an RPEQ-qualified structural engineer who can halt the test at any stage if the structural response indicates distress.
Proof load testing is particularly valuable for bridge assessment, floor capacity verification, and heritage structure assessment, situations where the structure's actual capacity may significantly exceed its calculated capacity due to unquantified contributions (composite action with non-structural elements, load sharing, membrane action in slabs). A successful proof load test demonstrates that the structure can carry the applied load with adequate margin, regardless of the analytical uncertainty.
TRSC integrates load testing with structural monitoring, using the measured structural response during the test to calibrate FEA models. The calibrated model then enables confident prediction of structural behaviour under load conditions that cannot be physically tested (ultimate loads, seismic loads, dynamic loads). This combined approach provides the most reliable assessment of existing structural capacity.
Speak with an RPEQ-qualified structural engineer about deploying this technology on your asset.
Applications
Bridge Capacity Verification
Proof loading of bridges to verify capacity for specific vehicle loads, demonstrating adequate capacity where analytical assessment produces uncertain or conservative results.
Floor Load Capacity Verification
Load testing of floor slabs to verify capacity for changed loading conditions, heavier equipment, increased occupancy, or change of use.
Heritage Structure Assessment
Controlled load testing of heritage structures where analysis is limited by uncertainty in material properties, connection details, and structural system behaviour.
FEA Model Calibration
Using measured structural response during load testing to calibrate finite element models, enabling confident analytical prediction beyond the tested load range.
Post-Repair Verification
Load testing of repaired or strengthened structures to verify that the remediation has achieved the required capacity enhancement.
Crane & Equipment Installation
Load testing of structural elements that will support heavy equipment, verifying adequate capacity before committing to equipment installation.
Frequently Asked Questions
When is load testing warranted?
Load testing is warranted when analytical assessment cannot provide sufficient confidence in structural capacity, typically because material properties are uncertain, connection details are unknown, the structural system includes unquantified beneficial effects (composite action, membrane effect), or the analytical method is known to be conservative for the structure type. Load testing is also used when the cost of the alternative (structural strengthening based on conservative analysis) exceeds the cost of demonstrating adequate capacity through testing.
What are the risks of load testing?
The primary risk is overloading the structure to the point of damage. TRSC manages this risk through continuous monitoring during loading, deflection gauges, strain sensors, and crack monitors provide real-time data on structural response. The test is controlled by an RPEQ engineer who can halt loading at any stage. Load stages are incremental, allowing the engineer to assess behaviour at each stage before proceeding. Distress indicators (excessive deflection, non-linearity, cracking) trigger an immediate halt.
What happens if a load test fails?
If a structure fails to meet the load test criteria (excessive deflection, inadequate recovery, or signs of distress), the test is terminated and the structure is immediately assessed for any damage caused during the test. The test results are documented and inform subsequent decisions about load restriction, strengthening, or replacement. A failed load test provides valuable information about actual capacity that informs the remediation design.
Deploy Load on your asset
Every investigation begins with a direct conversation with an RPEQ-qualified structural engineer. No sales intermediary, contact TRSC to discuss whether load testing / proof loading is appropriate for your structural question.