Long-term movements of highway bridge approach embankments and pavements are described and factors that may lead to settlement of highway bridge approach pavements are discussed. Six case histories are presented. The bridge approach sites were observed at different times during the period 1966 to 1985. At four sites, lateral movements, measured from slope inclinometers, of the approach embankments were monitored over time periods ranging from 8 to 14 years. Settlements of the highway bridge approaches were monitored some three to four years after paving. Estimated and observed settlements of the foundations at the study sites were obtained for a length of time sufficient to establish settlement patterns over long-term time periods. Subsurface explorations were conducted prior to and after construction. Triaxial tests were performed on foundation and embankment samples. Based on triaxial shear strengths and long-term seepage measurements, long-term factors of safety of the approach embankments were calculated. An empirical method of estimating the rate of foundation settlement is presented. This method appears to yield settlement estimates that agree better with observed settlements than estimated settlements based on laboratory parameters. An empirical method for estimating the long-term settlements of highway approach embankments is presented. This method may be useful in deciding whether permanent or temporary approach pavements should be installed. With regard to the design and construction of highway bridge approach embankments and pavements, several recommendations are presented.

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The contents of this report reflect the views of the author who is responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the Kentucky Transportation Cabinet, the Federal Highway Administration, nor the University of Kentucky. This report does not constitute a standard, specification, or regulation.