Figure 7 shows that the horizontal shear
fatigue load range per unit length generated in the first
phase of the cyclic testing exceeded the anticipated load
range for the design bridge as well as the design resistances
at the girder-haunch and haunch-deck interfaces.
Each successive loading step surpassed the design capacities
by a larger margin. In the figure, ΔVf indicates the
range of vertical shear force on the beam, which is equal
to half the live load applied through the actuators onto the
beam. The circle-arrow marker indicates that the specimen
capacity was sufficient to resist the applied loads
throughout each loading phase, constituting a fatigue
runout at that load.
After the cyclic loading program, each specimen was
subjected to static loading in the second phase of the testing.
The basic loading setup was the same as that used for
the cyclic loading, with additional static hydraulic actuators
added to achieve the necessary higher loads. The test
specimens were loaded in a stepwise fashion until failure.