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Abstract
The use of nondestructive evaluation tools to assess the structural
condition of bridge infrastructures gained wide acceptance. As a result, many
countries direct their researches to this field. In this thesis, the most recent
researches on nondestructive evaluation of the dynamic behaviour of box girder
bridges are highlighted and the different concepts in this field are illustrated.
Special attention is given to the application of modal testing as a global
evaluation method of bridges. This includes the use of both frequency shifts and
changes in mode shapes as indicators for damage presence.
It was found that research was carried out in laboratories, and as a result
environmental effects were not considered. With recommendations to carry out
experimental tests in site, this study has three folds:
The first focused on studying the dynamic characteristics of several
prototype box girder bridges, including reinforced and prestressed concrete
bridges. The study was performed analytically using the finite element analysis.
Frequencies of vibration and mode shapes were determined and were compared
to those of similar bridges available in the previous literature.
In the second phase, the results of a dynamic test on a long-span
prestressed box girder bridge were utilized to obtain its fundamental frequency
and the corresponding mode shape. The process of obtaining these
characteristics was thoroughly explained and applied.