McMahon & Mann provided geotechnical engineering services to the project designer for the design of the foundations for the abutments. The soil borings indicated a dense gravel layer over clay soils which extended to more than 100 feet deep. Because of the deep soft clay deposit a pile foundation was considered impractical.

A spread footing foundation was selected to support the new bridge abutments. McMahon & Mann sampled and tested the clay soil for consolidation characteristics. The boring and testing data were used to analyze the allowable foundation bearing pressure and to estimate the settlement of the proposed foundation system. The bridge was designed with a shallow foundation and sheet pile walls to protect the shallow foundations from scour.