• Ground Improvement
• Illinois DOT
• Hazelwood Schools
• Wentzville
• West Memphis
• St. Peters Rec Plex
• Sheboygan Police Station
• Lange-Stegman
• Kennett
• Bluffton Ethanol
• Wheeler Center
• Earth Retention
• Metrolink
• Warrenton Copper
• MoDot
• Centrum Properties
• Pinnacle Tunnel
• Metropolitan Sewer
• Drilled Shafts
• Pinnacle Casino
• Eads Bridge
• Driven Pile
• MCI WorldCom
• Ameren UE
• Augercast
• Proctor & Gamble
• Micropile
• St. Louis Zoo
• Cupples Station

Service: Earth Retention System
The Creve Coeur Pavilion was a development consisting of retail, theatre, parking garage and restaurants. It was bordered on one side by a roadway with a large amount of underground utilities, which precluded running tiebacks or soil anchors underneath for a shoring system. However, as the project required a 17-ft deep excavation abutting the roadway, a 12,000 sq ft modified secant pier wall was developed by Subsurface Constructors to act as a cantilevered shoring system; eliminating the need for tiebacks or bracing.

A secant pier wall is typically made by drilling a series of piers in tangent to one another around the perimeter of a site to be excavated, forming a continuous wall. As this can be expensive and time consuming to install, we developed a modified system. The piers were spaced out on 5-ft centers instead of tangent, leaving gaps between them. As the site was excavated, welded wire mesh and a drain fabric were placed on the face of the excavation and anchored to the piers. Gunnite was then sprayed on to the face to complete the wall system. This allowed the wall to be built from the top down and used drilled piers as both cantilevered secant piers and as solder beams, with the gunnite acting as the lagging. The gunnite further acted as the finished retaining wall, saving money and time for the owner.

As Subsurface acted as both designer and contractor, we were able to quickly adapt to changing conditions; quickly turning around any needed design changes. This efficiency in design/ build shoring further aided in compressing the schedule by avoiding delays caused by the normal bureaucracy of subcontractor, general contractor, architect, and structural engineer using a "request for information" and "change order" type system.

• Owner: Centrum Properties
• General Contractor: C. Rallo
• Soils Engineer: Shively
• Drilling Equipment: Watson 3100