Adjacent precast,
prestressed box beam bridges have a history of poor performance and have been
observed to exhibit common types of deterioration including longitudinal
cracking, concrete spalling, and deterioration of the concrete top flange. The nature of these types of deterioration
leads to uncertainty of the extent and effect of deterioration on structural
behavior. Due to limitations in previous
research and understanding of the strength of deteriorated box beam bridges,
conservative assumptions are being made for the assessment and load rating of
these bridges. Furthermore, the design
of new box beam bridges, which can offer an efficient and economical solution,
is often discouraged due to poor past performance. Therefore, the objective of this research is
to develop improved recommendations for the inspection, load rating, and design
of adjacent box beam bridges. Through a
series of bridge inspections, deteriorated box beams were identified and
acquired for experimental testing. The
extent of corrosion was determined through visual inspection, non-destructive
evaluation, and destructive evaluation.
Non-destructive tests (NDT) included the use of connectionless
electrical pulse response analysis (CEPRA), ground penetrating radar (GPR), and
half-cell potentials. The deteriorated
capacity was determined through structural testing, and an analysis procedure
was developed to estimate deteriorated behavior. A rehabilitation procedure was also developed
to restore load transfer of adjacent beams in cases where shear key failures
are suspected. Based on the
understanding of deterioration developed through study of deteriorated adjacent
box beam bridges, improved inspection and load rating procedure are provided along
with design recommendations for the next generation of box beam bridges.