Crux executed the design and construction of 41 post-tensioned soil anchors to stabilize a steep, failure-prone slope with limited surface access and challenging geotechnical conditions. Crux and the owner’s geotechnical engineer Geosyntec, collaborated to develop a design approach that integrated subsurface investigation data, slope stability modeling, and load-path analysis to determine optimal anchor placement, inclination, and embedment depths necessary to achieve the required factors of safety. Each anchor utilized encapsulated five-strand high-strength steel tendons and precast concrete thrust blocks to provide active and permanent stabilization.

Installation required sequenced coordination with the excavation contractor to provide benching and backfill in planned stages to accommodate access by tracked drilling rigs. Excavation had to be precise to align with anchor drilling orientation and placement of concrete thrust blocks. Anchors were drilled to approximately 70 feet below ground surface to reach competent bearing zones identified during geotechnical analysis. Once drilled, strand anchors were inserted in the boreholes and grouted to ensure effective load transfer to the surrounding subgrade.

Each anchor was post-tensioned to more than 200,000 pounds of force and locked off at 150,000 pounds of force. After post-tensioning and design verification, all thrust blocks were buried to restore the site to its natural grade and appearance. To ensure long-term performance, permanent monitoring instrumentation was installed, allowing the owner to track slope movement and anchor load conditions over time. This enables proactive maintenance, including re-tensioning if required, and provides a data-driven approach to asset management.