A STRUCTURAL ANALYSIS OF BRIDGE ABUTMENTS CONSIDERING SCOUR AND CLIMATE CHANGE

Abstract

One of the most pressing issues facing the world today is climate change. With bridges playing such a critical role in society, it is extremely important for the effects of climate change on bridges to be considered, especially in terms of scour, the leading cause of bridge failures in the United States. Thus, the primary objective of this research was to investigate how climate change influences scour vulnerability and how that, in turn, affects the structural stability of bridge abutments. Of the climate change components, it was found that increases in intense precipitation would have the most effect on scour. Case studies of three bridges in the New Jersey area compared the effects of climate change effects. A further investigation was conducted for one of the bridges. Its recalculated scour depths, adjusted for increases in precipitation intensity, exceeded the footing limits for the three design floods. Using a finite element model of the abutment, soil springs under the footing were removed to simulate scour. The results indicated that with increasing amounts of scour, the abutment moves forward and rotates clockwise, away from the backfill. Stress analysis revealed that even with extreme amounts of scour, the concrete’s tensile strength was not exceeded. In terms of soil bearing capacity, when 30% or less of the footing soil remained, the maximum allowable soil bearing pressure was exceeded. Lastly, shear and moment failure were checked and found to not be likely modes of failure. From this structural analysis, it was observed that the abutment is adequate for all but the most extreme cases of scour for the discussed potential failure mechanisms.