Analysis and Performance Monitoring of a Spread Footing Bridge Foundation

Detailed foundation analyses showed the feasibility of supporting the abutments of a two-span bridge on spread footings founded on overconsolidated glacial till. Embankments were used to preload both abutment areas prior to footing construction to reduce long-term settlements to tolerable amounts. The design-build team worked with the Minnesota Department of Transportation to develop a cooperative instrumentation program to monitor bridge performance during construction and provide data for comparison with the anticipated foundation response during the staged construction process. Instrumentation included optical survey targets, inclinometers, earth pressure cells, and tiltmeters. Monitoring data indicated overall good agreement between predicted abutment behavior and the measured response.