ABSTRACT
Field tests have been widely adopted to monitor and validate the use of novel construction technologies and to perform an experimental evaluation of existing bridges. The AASHTO Manual for Bridge Evaluation defines two test methodologies: proof load tests and diagnostic load tests. Proof load tests are employed to estimate the maximum safe live load a bridge can withstand without undergoing inelastic deformation. Diagnostic load tests are used to better understand a bridge’s in-service response. Diagnostic load tests have largely proven that existing bridge superstructures possess additional strength capacity than predicted by analytical methods. This difference can be explained by considering some in-situ parameters that are beneficial to the bridge’s performance. This chapter introduces an example diagnostic load test conducted on the superstructure of Bridge A7957, built in Missouri, USA, to illustrate how experimental in-situ parameters can be included in the estimation of a bridge load rating. The experimental load rating resulted to be less conservative than the analytical load rating.
