| dc.description.abstract | The behavior of two 55 ft. long prestressed, composite steel beamconcrete
slab bridge units was studied. The type of unit tested is currently
used in county road bridge construction, where the use of prefabricated units
is especially economical.
In primary test phases, the first unit was subjected to 3 years of sustained
loading, over 2,000,000 cycles of fatigue loading and statically loaded
to failure. The second unit underwent 500,000 cycles of fatigue loading
and was statically loaded to its yield level.
In supplementary test phases, pushout-type specimens with channel and
stud shear connectors, identical to those in the bridge units, were studied
to determine the difference between the two connector types under sustained
.;Ird ultimate loading conditions. In addition, transverse slab strength tests
were performed at six locations on the first unit, and on six similar, simply
supported, control slabs. The transverse slab strength tests were performed
to verify that arching action occurs in the bridge slab. The presence of
arching action in the bridge slab changed the mode of slab failure from a
relatively ductile flexural failure, to a sudden punching failure at a much
higher concentrated load.
Test results were compared to theoretical predictions and AASHTO Specification
limitations. It was found that the behavior of the unit was
reasonably predictable, and that with a minor connection detail change, the
prestressed, composite steel beam design concept is suitable for county road
bridge use. | |
