Bridge Foundations for Hightstown Bypass

Abstract

This paper presents a case history of the foundations for seven bridges supported on spread footings bearing on overconsolidated clay. Conventional methods of analysis were used to estimate the elastic and consolidation settlements of the foundations. The settlements were monitored during and after construction for approximately 300 to 500 days. While the settlements for all the piers were overpredicted, the predictions for the abutment settlements were in accord with predictions except for one bridge. The differential settlements from pier to abutment were underpredicted, with values after bridge deck placement that were up to one-half of the total or eventual differential settlements. Differential settlements from the start of construction were up to three-quarters of the total. The paper concludes that the overprediction of pier settlements and the reason for the relatively accurate abutment settlements are both related to inherent limitations in the methods of analysis used.