University of California, Berkeley retained PB&A, Inc. to design the permanent Soil Nail earth retention system for the more than 83 ft. deep excavation for the new Stanley Hall. The structure is an 10-story building with seven levels above grade and three levels underground. The design called for up to 80 ft. long, double-corrosion protected Nails and galvanized shear plates.
The sloping site gives an uneven underground height for the building, so that at the east side there are only three levels below grade, consequently creating an unbalanced lateral soil pressure on the basement walls. The unbalanced lateral force would have been about 3X as much as the lateral seismic force to be supported by the internal bracing of the building had it not been for the innovative permanent earth retention system developed by PB&A. The system was designed to integrate with the structural framework of the building to form the most effective earth retention system.