PILING

Morris-Shea completes deep foundation for Alabama high-rise

Morris-Shea has installed 261 H-piles as an alternative to drilled shafts with rock socket

 Morris-Shea at work on the deep foundations for Ascend Apartments in downtown Birmingham, Alabama

Morris-Shea at work on the deep foundations for Ascend Apartments in downtown Birmingham, Alabama

The 17-story residential building's mixed-use design includes 198 student occupancy units, ground floor retail space, a second story parking garage, and a rooftop swimming pool. Morris-Shea installed 261 high-capacity H-piles as a value engineered alternative to the original specification for drilled shafts with rock sockets. The original foundation design raised budget concerns that impacted the project's feasibility.

The Morris-Shea team completed H-pile load testing and production pile installation in 20 working days. Subsurface conditions varied considerably from pile-to-pile with dolomite rock pinnacles and crevices requiring piles be driven to depths as shallow as 40ft and as deep as 120ft. Morris-Shea installed high-capacity 12x74 H-piles with a 200t working load, rather than typical 12x53 H-piles with a smaller 50t load. The high-capacity piles were driven in 60ft lengths to rock refusal with a PVE 50 rig using a 5t hydraulic hammer. The contractor performed a static load test to 400t prior to commencing installation to verify load capacity.

The Ascend Apartments jobsite sits atop the Knox Group Formation, a subsurface mineral deposit dominated by Copper Ridge dolomite. The H-piles are installed through residual clays to refusal at the dolomite bedrock. The depth of the piles is highly varied due to cavities and fracturing commonly found in this type of subsurface.