MO AM Water Intake - Saint Louis, MO

Project Introduction

During routine geotechnical drilling for a new water intake structure, REN identified a karstic void roughly 8 feet below the top of rock where the 90-foot-tall structure was to bear directly on limestone. Given the facility’s critical role and seismic, wind, and flood design demands, the foundation system required rapid rethinking in the field.

Key Highlights

• Discovered karst zone beneath assumed competent limestone at proposed bearing elevation
• Developed grout design and specifications to stabilize the karstic feature
• Introduced micropiles to transfer ~8,000 kips of load through the karst to competent rock below
• Encountered artesian water seams delivering ~60 gpm at working elevation
• Applied specialized grouting techniques to prevent washout around micropiles
• Coordinated closely with the General Contractor and Owner’s Engineer to first stop inflow and then install load-carrying micropiles

Conclusion

By combining specialty grouting, micropile design, and on-site collaboration, REN transformed an unexpected karst and artesian water challenge into a stable, resilient foundation system for a critical water intake structure.

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