Frosch, R. J., Bobet, A., & Khasawneh, Y. (2014). Reduction of bridge construction and maintenance costs through coupled geotechnical and structural design of integral abutment bridges (Joint Transportation Research Program Publication No. FHWA/IN/JTRP-2014/06). West Lafayette, IN: Purdue University. https://doi.org/10.5703/1288284315500
Elimination expansion joints in the superstructure of integral abutment bridges offers the advantage of reducing the initial and life cycle costs of the structure. However, such elimination may have an adverse effect on the displacement demand at the pile-abutment connection and on the earth pressures on the abutment wall due to the thermal expansion/contraction cycles of the bridge. These adverse effects have resulted in regulations that impose restrictions on the maximum length and skew angle of integral abutment bridges. This research consisted of a deep analysis of the problem by considering soil-structure interaction. The approach was multifaceted as it included experimental and numerical analysis. Upon calibration and verification of the constitutive model, it was used as part of a parametric analysis to provide recommendations for the design limits of integral abutment bridges.
The analysis results showed that active state earth pressure is reached after the first contraction cycle. The displacement demand on piles is a function of the abutment wall displacement. Larger displacement demand of the pile at the acute corner when compared to the obtuse corner was observed during expansion and contraction cycles. The inflection point of the piles deformed shape was found to be at relatively shallow depth. Concrete shrinkage and sequence of loading affected significantly the displacement demand of the supporting piles, lower displacement demand of piles during the expansion cycle and larger displacement demand during contraction cycles. The analysis showed that a 500 ft bridge with 60° skew will provide acceptable long term performance.
integral abutment bridges, soil-structure interaction, piles, constitutive models, numerical analysis, coupled thermal-displacement, larger scale test, physical model
Joint Transportation Research Program
Indiana Department of Transportation
West Lafayette, Indiana
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