Accommodates Height Restriction Installation
DeWaal Screw Piles are recommended by Morris-Shea as a Value Engineered alternative to the base bid micropiles. DeWaal Screw Piles were able to accommodate the project’s interior height restrictions. Pile load testing was performed in two locations to assure the VE concept achieved project specifications.
Economical Temporary Casing
A sacrificial bit is attached to the bottom of the DeWaal SP tool. Sectional casings with special quick disconnect couplings are added during drilling to achieve the required depth. The special DeWaal Screw Pile tooling forms a 14-inch diameter pile shaft with a concrete screw blade that projects out to 20-inches in diameter.
A remote controlled Fundex CD20 drill rig with 20 ton-meters of torque and 15 tons of crowd force is used to install the DeWaal Screw Piles. The rig has sectional leaders, which can be adjusted from 13 to 60-feet in length to accommodate various height restrictions.
In some height restricted applications sections of temporary casings with quick disconnect couplers are added during drilling to achieve required depth. Excavators with special tong attachments lift and maneuver the sectional casings.
Prefabricated welded steel cages were manufactured by Morris-Shea and shipped to the job site in sections at specified lengths. Once the DeWaal SP tooling is drilled to the required depth, cages are lowered into the temporary casings and spliced together to create full length reinforcement that satisfied the seismic design requirements.
Grout is discharged directly into the casings as they are extracted by the CD20 drill rig. The grout level inside the temporary casings is maintained above the working grade during tooling extraction to ensure positive head pressure within the casing. Morrris-Shea can manufacture high strength sand-cement grout on site with a volumetric mixer to ensure that grout is always fresh and piles were poured without delays.