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OCR for page 21
21
#8 C bar
& 2#6
2#6
2#6
2#6
2#6
2#6
2#6
2#6
2#4
2#4
2#4
2#4
2#4
2#4
2#4
2#4 2#4 2#4 2#4
2 1/2"
2 1/2"
2 1/2"
2 1/2"
2 1/2"
1 1/2"
1 1/2"
3" 3" 3" 3" 3" 3" 3" 3" 1'-0" 1'-0"
1'-0" 1'-0"
Figure 3.7. End zone reinforcement details of WA1L (proposed) and WA1R (LRFD).
specimens in the structures laboratory, a 10 × 24-in., 12,500 psi failure. Examples of the CIP deck and the deck cast during
concrete deck was formed and made composite with the fabrication of the specimens are shown in Figures 3.5 and
girder. Figures 3.12 through 3.14 show the details of the 3.9, respectively.
Florida specimens. To test the first end of a specimen, the specimen was sup-
ported at 6 in. from both ends, leaving an unsupported length
of 41 ft. A point load was applied at 12 ft from the end being
3.2.3 Test Setup
tested and 30 ft from the other end, as shown in Figure 3.15.
In order to simulate the decking system that would be Once the test on this end was complete, the support on this
placed on the girders in the actual bridge, a deck was cast end was moved 12 ft inside the specimen and the load setup
in place on top of the Tennessee and Florida specimens was placed 12 ft from the second support. This setup helped
in the structural laboratory, while a deck was cast mono- to test both ends of every specimen while avoiding any effect
lithically with the top flange during fabrication of the Vir- from the tested end on the performance of the second end of
ginia and Washington specimens in the precast yard. The the specimen.
existing vertical reinforcement was extended in deck to act Since the dead loads, applied after a girder is installed on a
as horizontal shear reinforcement to create a composite bridge, help in closing the end zone cracks, a clamping force
system. The deck weight helped to increase the amount of mechanism was provided in the test setup at 30 in. away from
stress in the bottom strands of prestressing steel at flexural the end of the girder in order to simulate this load. The clamp-
ing force was provided by using a hydraulic jack attached to a
self-equilibrium frame built around the specimen as shown
in Figures 3.16 and 3.17. This clamping force was calculated
2#4 2#4 2#4 2#4 2#4
as the balance between the reaction developed by the actual
bridge girder (due to the slab, barrier, wearing surface, and
utilities weight) and the reaction generated by the 42-ft long
specimen. The clamping mechanism was placed only at the
end being tested.
The load was applied at a rate of about 5 kips per second
in stages of 100 kips. After each additional 100 kips, the load-
1'-0" 1'-0" 1'-0" 1'-0"
ing was paused so that the girder could be checked and marked
for cracks. Once the estimated failure load was reached, the
loading was stopped and the girder was checked for signs of
failure and the cracks were marked. Then the loading was
Figure 3.8. End zone reinforcement details of WA2L resumed until failure was reached. In some cases, as will be
(no EZR) and WA2R (no EZR). discussed in the following sections, failure could not be
