Bridge Load Testing: State-of-The-Practice

Sreenivas Alampalli*, Dan M. Frangopol, Jesse Grimson, Marvin W. Halling, David E. Kosnik, Eva O.L. Lantsoght, David Yang, Y. Edward Zhou

*Corresponding author for this work

Research output: Contribution to journalReview articleScientificpeer-review

18 Citations (Scopus)
141 Downloads (Pure)


Bridge load testing can answer a variety of questions about bridge behavior that cannot be answered otherwise. The current governing codes and guidelines for bridge load testing in the United States are the 1998 NCHRP Manual for Bridge Rating through Load Testing and Chapter 8 of the AASHTO Manual for Bridge Evaluation. Over the last two decades, the practice of load testing has evolved, and its intersections with other fields have expanded. The outcomes of load tests have been used to keep bridges open cost-effectively without unnecessarily restricting legal loads, when theoretical analyses cannot yield insights representative of in-service performance. Load testing data can be further used to develop field-verified finite-element models of tested bridges to understand these structures better. In addition, structural reliability concepts can be used to estimate the probability of failure based on the results of load tests, and noncontact measurement techniques capturing large surfaces of bridges allow for better monitoring of structural responses. Given these developments, a new Transportation Research Board (TRB) Circular, Primer on Bridge Load Testing, has been developed. This document contains new proposals for interpreting the results of diagnostic load tests, loading protocols, and the determination of bridge load ratings based on the results of proof load tests. In addition, included provisions provide an estimation of the resulting reliability index and the remaining service life of a bridge based on load testing results. The benefit of load testing is illustrated based on a cost-benefit analysis. The current state-of-The-practice has demonstrated that load testing is an effective means for answering many important questions regarding bridge behavior that are critical to decisions on bridge maintenance or replacement. Load testing has evolved over its history, and the newly developed TRB Circular reflects this evolution in a practical way.

Original languageEnglish
Article number03120002
Number of pages17
JournalJournal of Bridge Engineering
Issue number3
Publication statusPublished - 2021

Bibliographical note

Accepted Author Manuscript


  • Bridge maintenance
  • Bridge tests
  • Codes and guidelines
  • Field tests
  • Instrumentation
  • Load testing


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