ABSTRACT
First, a preliminary short-term test was conducted in October 2015 (Table 1) on the nine spans with a focus on the superstructure response through an 18 tri-axial high accuracy servo-type accelerometer array deployed at the center of exterior girders of each span. The test was conducted during night when passage of many heavy trucks are expected. In total about three-hours of measurement was completed with a sampling frequency of 1000 Hz. Although the test was conducted under free-flow traffic, two 25 ton trucks also ran with 60 km/h speed on each lane in both directions which were equipped with MEMS type accelerometers on dashboard with a sampling frequency of 200 Hz. The trucks completed 5-6 passages on each lane during the three-hour measurement. The speeds of the trucks were verified during post-processing by inspecting the video footages, which were taken inside the car during measurement and also through tracking the measured impact type responses as the trucks pass the expansion joints depicted in Figure 1. The data gathered from the car bodies were later used to investigate the relationship between the dynamic response levels of the viaducts and the response levels of the vehicles. Moreover, displacement of one of the spans was also measured by utilizing Laser Doppler Vibrometer (LDV). The center point of G1 girder was set as measurement point, where an accelerometer was also installed on the bottom flange. Displacement estimation algorithm from acceleration measurement is verified by comparing the results with the LDV measurement data which will be explained in the following section.
