With more than 70 deep piles to drill at the bustling Pulaski Skyway Bridge in New Jersey, 3C Drilling LLC turned to Liebherr deep foundation machines for the large-scale project.
The machines' high performance, ease of use and adaptability to diverse soil conditions makes Liebherr a trusted partner to address complex foundation systems, said Liebherr.
Founded in 2002 as a small cell tower drilling company, 3C Drilling LLC has grown into an industry leader in drilling and foundation installation, possessing decades of combined industry knowledge. The women-owned company specializes in caissons, drilling, micropiles, helical piles and mini piles.
With more than 20 years of experience, 3C Drilling has multiple Liebherr deep foundation machines and purchased an additional Liebherr LB 45 drilling rig to assist with a large foundation project at the Pulaski bridge in Kearny, N.J.
"We chose Liebherr LB 45 because it delivered the most power possible with the smallest footprint, which was exactly what we needed for this project," said Alexandra Cook, COO of 3C Drilling LLC.
Handling approximately 67,000 crossings a day, the Pulaski Skyway Bridge spans 3.5 mi. across the Passaic and Hackensack rivers connecting Newark, N.J., to Jersey City, N.J. One of the major challenges with this project is the need to install deep piles with a limited height restriction in place so work can be completed under the bridge, which remains in use. 3C is actively running two crews to assist with schedule acceleration, however, it is expected to be on site for one two years.
3C Drilling is operating a combination of Liebherr drilling rigs, including the modular design of the leader on both the Liebherr LB 45 and LB 30 to install the shafts at various heights. When the project first began, the LB 45 was used with 26-ft. folding leader configuration, but as the project demands shifted, the machine was converted to "low head" utilizing the same leader in a different configuration with only a change of crowd ropes required. With the change, the LB 45 can be used to install piles sections of the bridge and remain under the height requirement.
The LB 30 drilling rig uses the modular leader design; it also is set up in low head configuration to access drilling needs under lower height requirements than the LB 45 can reach. Additionally, 3C Drilling has the option to install its ultra low head leader for the LB 30 to achieve even more of a reduction in machine height. The current configuration paired with a new Kelly bar allows the 3C team to reach a deep drilling depth, using a conventional drill rig while remaining under height requirements in place.
Ultimately, 3C Drilling is installing 75 drilled shafts and one sacrificial demonstration shaft for the rehabilitation of bridge piers along the Pulaski Skyway. The drilled shafts are 60 in. in diameter with 54-in. rock sockets, and the varying depths of the foundations range from 130 in. to 150 in.
