For a speed of 55 MPH, the maximum measured midspan deflections for all girders is shown in figure 9. The equivalent values obtained from the static load test with vehicles of the same weight are shown in the same figure. Figure 10(a) shows a typical time-acceleration relationship for a 35 MPH vehicle speed. Figure 10(b) shows a typical time-deflection relationship for a 55 MPH vehicle speed.
The fundamental natural frequency of the bridge was calculated by the power spectrum of time-acceleration measured data as shown in Figure 10(c). The dominant natural frequency of this test was about 7.0 Hz(cps).
Static Test of Span B2
The static load test was performed on span 2. Figure 11 shows the load position of the testing vehicles during the static test. A linear relationship exists between the applied load and the measured deflections and, also, between the applied loads and measured strains for all the girders. These results indicate a maximum deflection and strain of 0.755 inches and 263 microstrain, respectively. Neither cracking nor other signs of distress were observed at the maximum applied load.