Performance Evaluation of Semi-Integral Abutment Bridge Ends Based on Approach Slab Details

Abstract

Semi-integral abutments help increase the service life of bridges by eliminating the issues associated with the use of expansion joints. However, the behavior of such abutments under service loads has complexities, especially in their connections to approach slabs. This motivated the current study to systematically investigate the in-service performance of semi-integral abutment bridges through a holistic suite of visual inspections, long-term monitoring programs, and numerical analyses. For this purpose, nine bridges were visually inspected to identify common problems associated with semi-integral abutments, including joint issues, embankment erosion, cracks in approach slabs, and water leakage. Additionally, two bridges were instrumented with various sensors at the time of construction and monitored to understand their long-term behavior under service loads. This was with a focus on top and bottom approach slab strains, longitudinal and transverse abutment displacements, and earth pressures on abutment walls. Two bridges with a high skew angle was further studied numerically in four different design configurations to evaluate the stress, strain, and displacement distributions in the approach slab and tie bars. The numerical investigations also assessed the bridge end’s response to embankment settlement, given the frequent occurrence of settlement-related issues. The study’s results and findings provided new insights into key structural response measures paired with relevant recommendations. The outcome facilitates the design and assessment of semi-integral abutment bridge ends, taking into account various approach slab details.