Ground Improvement

Location: Puget Sound Area, WA

Project Partner: Private Energy Company (Owner)

Challenge: Reinforce liquefiable soils up to a maximum depth of 100 feet to mitigate the effects of liquefaction and lateral spread. Provide a minimum of 4500-psf bearing capacity for future mechanical, piping, and tank systems. In addition to native silts and sands, the site soil profile included near surface debris that posed an obstacle to penetration and maintaining the specified verticality tolerance.

Overview: Condon-Johnson contracted directly with a private energy company (Owner) to install Rigid Inclusions for construction of a new natural gas facility. Ground Improvement using Rigid Inclusions was used to mitigate the effects of both seismically induced soil liquefaction settlement and lateral spreading. Moreover, the Rigid Inclusions were designed to reduce short and long term static consolidation settlements for the new natural gas facility.

Results: Condon-Johnson conducted a static settlement test program at the beginning of the project to verify the project design parameters. Upon completion of the test program, Condon-Johnson completed the work by installing over 2,000 3-foot diameter Rigid Inclusions up to 100 feet in length. Over 50,000-cyds of concrete were placed, documented and successfully tested. The Rigid Inclusion ground improvement system was installed on schedule and on budget using Bauer BG-46 and BG-39 drill rigs.