Historic Remediation with Helical Piles

The Los Angeles County Sheriff’s Department’s new juvenile facility and training academy was opened in 1947 and later named the Biscailuz Center. A lack of space led to its closure in 1984. After 30 years of being vacant, the Biscailuz Training Center (BC Academy) was re-opened after renovations including foundation underpinning and straightening of the building.

When the decision was made to expand and re-open BC Academy, engineering experts were needed to preserve and renovate its historic buildings. Building B3, dating back to the 1940s, needed to be brought up to current codes. It was built on undocumented fill and the second story was out of plumb by over 6 inches.

The second story was shored so the old foundation could be removed. Even this early stage of the project proved challenging due to limited space with which to shore the building and having to work around bracing to install the helical piles. Utilizing limited access equipment, CHANCE SS175 helical piles were installed to provide axial loading capacity as well as lateral capacity within the replaced foundation. With no concrete to cure, the piles could be tested immediately.

Meticulous testing was required throughout this project. Vertical and battered sacrificial test piles were installed and tested. Vertical and battered production piles were tested in compression. The battered piles were installed at a 45-degree angle for lateral resistance within the proposed foundation. The vertical tests proved much easier than the battered tests in compression due to the challenge of limited space and reactionary forces. Learn more about load testing.

The entire project required 37 vertical and 6 battered helical piles reaching depths of 52 ft. A safety factor of 3x the design load of 29 kips was used.

Once all helical piles were installed and testing was complete, the new foundation was placed in its original location over the CHANCE helical piles and, at the direction of installer JRW Foundation Systems (JRWFS), framing was then replaced out of plumb. Under separate contract, JRWFS designed a method to re-plumb the second story utilizing cables and turnbuckles. Afterwards, sheer walls were installed, and the cable bracing was removed.

Working with Hadley Engineering, JRWFS used CHANCE helical piles to restore the foundations structural integrity through 30’ of undocumented fill. JRWFS came up with the design to straighten the second story in a way previously designed sheer walls could be installed without modification. It took five (5) days to straighten the building. It was verified by L.A. County surveyors to be perfectly plumb.