Exploratory Study of Nondestructive Parallel Seismic Testing Challenges in Estimating the Depth of Unknown Wood Bridge Foundations

Abstract

Nondestructive methods have been extensively used to characterize unknown bridge foundations. Among various nondestructive methods, conventional and reverse parallel seismic (PS) methods are considered proper methods capable of determining the depth of piles made of common construction materials, such as wood, steel, and reinforced concrete. Previous studies have indicated that the PS tests results are influenced by the distance between the borehole and the tested pile, the pile length, the stiffness of the surrounding soil, and the defects of the pile. In the current study, the method of striking is identified and discussed as another influencing factor. Several conventional PS tests were conducted on wood piles of a highway bridge. The conventional PS results showed that vertical, inclined, and horizontal striking methods can produce results with various levels of reliability. However, the vertical and the inclined striking can produce more interpretable signals compared to the horizontal striking. In addition, the results of this study showed that the conditions and stiffness of the foundation may be another factor that can adversely affect the success of reverse PS tests.