GET provided the soils explorations and geotechnical engineering evaluations for the Michigan Avenue Bridge Replacement over the CSX Railroad south of I-10. The project included the replacement of the existing bridge structure with two new 72-foot spans making the new bridge approximately 80 feet shorter than the original bridge but elevated 2 to 3 feet higher. The new bridge abutments were constructed 40 feet inside the location of the existing abutments.
Deep foundations were recommended for the new bridge structure. Potential long-term settlement of the bridge abutments and limited space between the two existing railroad tracks made shallow foundations impractical. Driven piles were recommended for the abutments with drilled shafts recommended for the center bent located between the railroad tracks.
Due to the shortened bridge length, mechanically stabilized earth walls were constructed to retain soils at the new abutments. Since the replacement bridge was 2 to 3 feet higher than the existing structure, approach embankments were analyzed for stability and recommendations provided for fill soil placement.
During construction, GET provided geotechnical engineering support and construction inspection services through its Construction Engineering Inspection contract with the Alabama Department of Transportation.