New York City Condominiums
Con-Tech Systems Ltd. supplied Titan Hollow Bar material and Obermann grouting equipment to the Presscrete Company of
This project consisted of installing 90 - 75 ton Titan 73/45 micropiles to a depth of 55’ in native silty sand soil using an EGT 1500 drill rig and an Obermann VS-63-20 grout plant. Each Titan 73 pile consisted of a 200 mm (7.9”) clay bit and 165 mm (6.5”) centralizers evenly spaced every 3 m (10’). A 0.4 W:C ratio grout mix was pumped at a maximum rate of 14 gpm and reaching a maximum pressure of 200 PSI. A performance test was conducted on a sacrificial Titan 73/45 mm pile and was successfully tested to 180 tons, well exceeding the 2 times design load requirement.
This project was unique as the piles located in the elevator shaft had to be exhumed and cutoff at a lower elevation. This allows us to see the grout column that surrounds the Titan 73 pile. The excellent grout coverage that is created when the Titan system is properly installed under pressure grouting is well shown in the photos. The average of the exposed column is 10”, or approximately 1.5 times the bit diameter. This increased column diameter which is not accounted for when the pile is structurally designed is what allowed this pile to reach almost 2.5 times the design load. The photo also illustrates the quality of corrosion protection created by the grout column.
At a Glance
Project: New York City Condominium
Contractor: Presscrete Company, South Plainfield, NJ