Proof-Load Factors and Reliability

For a complete implementation of second moment reliability concepts in structural design codes, rules must be established for proof-loading tests on the basis of a safety index or of proof-load factors derived therefrom. The safety index after test is defined conveniently (as a distance in an associated Gaussian probability space) as an extended definition of the Hasofer-Lind safety index. Limitations of this safety index in the context of proof-load tests are considered. Two categories are studied: Active proof-load tests, in which the purpose is to determine the optimal design parameter given a successful test on a particular structure prior to service; and passive tests, leading to reliability statements about a structure during or prior to service. Examples show how to calculate the proof-load factors. Current building standards provisions on proof-load tests are examined from the reliability point of view.