Evaluation of Bridge Abutment with Ultraseismic Waveform Tomography: Field Data Application

This paper presents an application of ultraseismic waveform tomography for condition evaluation (determination of elastic properties) and the unknown depth of a concrete bridge abutment. A newly developed waveform tomography technique for bounded medium (e.g. thin plate) was applied to an ultraseismic dataset collected on a 30-m long bridge in New York City. The dataset was measured on the top of abutment using 24 100-Hz vertical geophones uniformly spaced at 1.2 m apart, and a 3-lb hammer source to induce wave energy. The results revealed that the waveform analysis was able to characterize both the S-wave and P-wave velocities (Vs and Vp) of the abutments and the supporting soils. The true abutment depth of 5.7 m was generally identified in both inverted Vs and Vp profiles. The main advantages of this approach include: (1) data acquisition on top of the abutment is more convenient and cost effective compared to measurements from the ground, boreholes, or river-beds for water bridges; and (2) abutment concrete physical elastic properties are characterized at high resolution in cells. To our best understanding, this is the first reported study using the waveform tomography on field data for assessment of concrete abutments or wall-type structures.