This report presents the results of a research effort to assemble, review, and evaluate all available data relating to the load capacity of highway bridges. The primary objective of the research was to identify and evaluate aspects of bridge behaviour that are not normally considered in load capacity estimates but which may be important in enhancing the actual load capacity of a bridge. The term "bridge load capacity" was examined and found to contain a degree of ambiguity, meaning either the limit of elastic behaviour or ultimate load capacity. Accordingly, the effects of the variables considered were evaluated in terms of both definitions with emphasis on the limit of elastic behaviour. The effect of lateral distribution of load, although not an aspect of behaviour in the strictest sense, was found to have a significant influence on the load capacity predicted. Two variables discussed in some depth in the report are the effects of unintended composite action and unintended continuity, both of which may be important in predicting the response of a bridge but which are typically difficult to quantify for a specific situation without benefit of some testing.
Abstract