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MoDOT I-70 Connector for New Mississippi River Bridge

Owner: Missouri Department of Transportation (MoDOT)
Client: Crawford, Murphy, & Tilly, Inc.
Location: St. Louis, Missouri
Services: Environmental

Geotechnology provided environmental consulting, sampling and testing to support the design and construction of the I-70 Missouri Connector and Main Span Corridor project related to the New I-70 Mississippi River Bridge. The four-lane, cable-stayed main span, located south of the McKinley Bridge and about a mile north of the Martin Luther King Bridge will connect the City of St. Louis to the Metro East area of Illinois.

To assist the design team in evaluating the historically urban, industrial area, Phase II Environmental Site Assessments were needed to prepare for construction. The project area included properties both west of Broadway (MoDOT Connector) and east of Broadway (Main Span Corridor). The Assessment identified existing and prior site uses including a prison work release center, railroad track, storage for rubble collected from building demolition throughout the city, cement storage and packing, mattress factory, scrap metal and rubber warehouse, warehouse, railroad tie storage, gasoline filling station, and furniture frame manufacturing company.

The scope of services included reviewing the environmental assessment reports prepared by others, and sampling and testing in conjunction with the geotechnical investigation where impacted soil and/or groundwater were suspected or encountered. Thirty environmental borings were advanced, samples extracted and tested for a suite of parameters including volatile organic compounds, metals and PCBs. Monitoring wells were also installed in borings where water was encountered, and groundwater was later sampled and tested for contamination. All field activities were conducted according to the Missouri Department of Natural Resources (MDNR) regulations and testing was in accordance with MDNR Missouri Risk-Based Corrective Action (MRBCA) guidelines.