Crazy Horse Memorial Tower Crane Foundation

Building Access Where Access Has Always Been the Challenge

Carving the Crazy Horse Memorial has always been defined by access. How people, equipment, and massive blocks of granite safely move across a steep, complex mountainside shapes every decision. To expand that access, the Memorial installed a high-capacity tower crane designed to reach nearly every working face of the mountain. The Liebherr 1000 EC-H 40 Litronic crane stands more than 215 feet tall and has a horizontal reach of 267 feet.

Our team was engaged in early 2024 to investigate and design a rock-anchored foundation capable of resisting extraordinary loads. The work began with an assessment of the rock mass characterization, including deep rock core drilling that extended 50 feet into the mountain, followed by detailed laboratory testing to characterize the strength of two distinct rock types. In our Rapid City rock mechanics lab, we conducted custom direct shear testing to determine the bond between grout and the underlying schist and granite to confirm anchor behavior under the anticipated loads.

Using this information, RESPEC designed an 8-foot-thick, heavily reinforced concrete foundation supported by 16 large-diameter rock anchors socketed deep into competent rock. Each anchor was tested and locked off at substantial loads (exceeding 200,000 pounds), providing the capacity needed to resist crane-overturning forces measured in the millions of pounds. The entire system was modeled using advanced 3D finite element software and integrated with the Memorial’s LiDAR scans to confirm constructability and fit within the mountain itself. The 8-foot-thick mat foundation’s octagonal shape was selected to provide an optimal location condition for safely moving massive blocks of granite in excess of 30 tons and customized robotic rock-carving equipment around the mountain, accelerating the carving of the largest monumental sculptures.

Results That Stand for Generations

The completed foundation supports a high-capacity crane that expands access across the mountain and allows work to be carried out with greater control and consistency. Designed to resist extreme loads and anchored deep into competent rock, the foundation provides the stability needed for safe, long-term operations in a demanding environment. For RESPEC, the project reflects the value of bringing the right expertise together in service of a monument meant to be built to last.