John Rogie, President of California Push Technology in Menlo Park, CA, repositions the 6625CPT machine next to an exterior wall of the Crocker Art Museum in Sacramento, CA. Maneuvering the machine immediately adjacent to the building’s foundation was critical to the success of obtaining CPT (cone penetration test) logs for the museum’s expansion process.

California Museum in Early Phases of Expansion Project

California Push Technologies in Menlo Park, CA, recently completed a multi-day, multi-visit project to assist a very old museum in the early phases of a 100,000-square-foot expansion project.

The Crocker Art Museum, in Sacramento, CA, founded in 1885, is the oldest museum in the western United States and is in the initial phases of a large restoration and expansion project. The City of Sacramento lies at the confluence of a number of major riverine systems. In several areas of the city, historic structures have been undergoing differential settlement for many decades due to underlying soft soils. As part of the museum restoration project, California Push Technologies is performing on-site cone penetration testing (CPT) services to establish baseline geotechnical conditions prior to a compaction grouting phase which will help stabilize the ground beneath the historic structure.

The project required that CPT logs be run as close to the existing foundation as possible. According to John Rogie, President of California Push Technologies, a registered Professional Geologist, and principal rig operator, “Our Geoprobe 6625CPT was THE ONLY rig for a job like this! The museum also requested we not tear up their grounds,” John added, “and our highly-maneuverable and lightweight rig, coupled with a set of mats allowed us to leave their lawns unscathed.”

California Push Technologies was able to easily position and operate their 6625CPT machine in very tight confines next to the museum’s exterior walls.

The project’s scope of services included performing pre- and post-compaction cone penetration tests in order to establish design and improvement criteria. Because compaction grouting will occur immediately adjacent to the museum’s perimeter foundation, a CPT rig capable of operating very close to the building was required to do the work. It was also extremely important that the museum facilities remain unharmed and undisturbed. John knew when the call came in that his Geoprobe® machine was the right rig for the project. “The 6625CPT rig was the ideal push platform for a limited access job like this,” John said. “We were hired because of our capabilities with the 6625CPT.”

John, and Jerry Droze, Facilities and Maintenance Manager for California Push Technologies, performed nearly 50 cone penetration tests at the site, all to a depth of 35 feet. John’s company is slated to return to the site upon completion of the compaction grouting in order to perform a final set of confirmatory CPT soundings. “The

6625CPT performed flawlessly,” John said. “The ability to position CPT sounding locations immediately adjacent to the building’s foundation was critical to the success of this project”. Jerry, who also is in charge of the company’s maintenance program, said, “There were a couple of days when the outside temperatures were close to 100 degrees fahrenheit. The well-organized design of the 6625CPT made working in those temperatures safe, and the rig’s cooling system performed exceptionally well.”

Wallace Kuhl & Associates (WKA) in Sacramento is the geotechnical engineering consultant for the museum project. They contacted Geoprobe Systems® for assistance in finding Geoprobe® machine owners in the Sacramento area to hire for the project. Through an established, complementary referral service offered to all Geoprobe® machine owners, WKA contacted several California Geoprobe® owners and ultimately hired California Push Technologies for the project.

Soft clays and silts, typical of riverine and deltaic systems, underlie the Crocker Art Museum site. The continuous, quantitative data logged during the cone penetration testing allows the engineer to design the ground improvement project in order to arrest settlement of the overlying structures.