The new South Bed Tower for FL Hospital required an excavation 20 to 30 ft. deep for the 5 ft. thick mat foundation. An earth retention system was required in order to protect the adjacent Emergency Drive and Rollins St. and provide access space and laydown area along adjacent Lake Estelle. The natural soils consisted of loose to medium dense fine sands to some depth below subgrade with the groundwater table at 5 to 10 ft. below existing grade. In order to minimize any noise or vibrations that could impact the existing hospital operations, no pile driving was allowed.

 

Schnabel Foundation Company designed and built a temporary earth retention system for this project consisting of soldier beams and wood lagging supported by rotary pressure-injected tiebacks. Drilled-in soldier beams were installed using a 24 inch CFA drill in swinging leads suspended by a large crawler crane. The soldier beam holes were filled with a weak flowable fill as the auger was extracted and then the H-piles were placed in each hole. In order to maintain a dry excavation, dewatering was performed by another subcontractor using deep wells on the excavation perimeter.