I-90 Over Six Mile Creek – Design-Build

SAI was responsible for the final design/build of over one mile of full-depth roadway reconstruction, with realignment of the west-bound lanes, and the replacement design of two continuous steel plate girder dual structures over Six Mile Creek, Erie County, PA.

Physical features:

• 796′ three-span continuous steel plate girder dual structures.
• Bridge deck consists of two 12-0 lanes, and 12′ 8″ shoulders for 37,770 sf of deck area (out/out).
• Approximately one mile of full-depth roadway reconstruction with realignment of the west-bound lanes on a four-lane limited access highway with an ADT of 59,000 (2029).
• Substructure consists of concrete abutments supported on piles with multi-column concrete bents on spread footings, with stepped rectangular columns.

Other features:

• Dual structures were used to replace deficient trusses.
• 170′ tall piers at the bottom of a gorge and designed an access road that required moving 200,000 CY of material to allow for construction.
• Widened roadway embankment for approaches and to account for settlements and down-drag issues with the abutments.
• Girders braced against existing truss for lateral support during erection to avoid the need for support columns constructed on steep embankment.
• Traffic maintained via phased construction with two lanes of traffic maintained in each direction, with cross-overs on a divided highway.