I-210 Cove Lane Interchange Improves Casino Access

GeoEngineers completed a geotechnical engineering evaluation, design and construction monitoring for the new Interstate 210 (I-210) overpass of Cove Lane in Lake Charles, Louisiana. This fast-paced project required our team to mobilize five different drill rigs for explorations and staff from offices across the country in order to meet the schedule requirements.

The goal was a new interchange to raise I-210 and extend Cove Lane from a new roundabout at W. Prien Lake Road to connect with a new public roadway running below I-210 to the new Golden Nugget Casino. The project was funded by an intergovernmental cooperative agreement between the state Department of Transportation and Development (DOTD), Lake Charles-area governmental agencies, Ameristar Casinos, Inc. and others.

Approach

GeoEngineers provided a complete geotechnical investigation, including 128 explorations (43 drilled soil borings and 85 CPTs) to depths of 20 to 120 feet, and associated soil laboratory testing for the I-210 overpass structure with approach embankments and ramps. The proposed embankment overpass structure used a tight urban diamond configuration for the new Cove Lane interchange.

The project was complicated by the historical meandering of the Calcasieu River, which created a widely varying subsurface geology. Our geotechnical engineers carefully analyzed the stability, differential settlement and other factors for geology ranging from over-consolidated Pleistocene clay to soft alluvial deposits.

The close proximity to live traffic throughout the project implementation caused an additional challenge. The team took extra measures to ensure the safety of everyone working on the project and members of the public using the roadways.

The team used Pile Driving Analyzer (PDA) equipment to evaluate and monitor installation of one in every 50 piles placed for acceptance of the over 8,000 driven piles. Careful data collection and record-keeping by GeoEngineers throughout the project proved useful to the DOTD and teaming partners.

Our engineers designed a staged 11-foot surcharge load with 60-foot wick drains over a soft portion of the project site, where I-210 exited to the Cline Canal Bridge, in order to speed up the settlement process and keep the fast-paced project on schedule.

Results

The GeoEngineers’ team completed engineering analyses and provided design and recommendations for numerous portions of this large project, including:

• Concrete and asphalt pavement design sections.
• Driven timber and concrete pile capacities for the overpass structure, Cline Canal bridge and subgrade improvements below the embankments and ramps (in accordance with the American Association of State Highway and Transportation Officials’ Load and Resistance Factor Design specifications for highway bridges).
• Embankment settlement magnitudes and time rates.
• Mechanically stabilized earth (MSE) wall analyses for slope stability, sliding, bearing and overturning.
• Wick drain and surcharge design to reduce post-construction settlement.
• Staged loading of the Cline Canal embankment to reduce potential subgrade instability.