Project Snapshop
Project: Downtown San Francisco Excavation Support
Location: San Francisco, California
Application: Excavation strut preloading
Challenge: Apply up to 700 tons across three excavation levels
Solution: Custom fixtures with calibrated 355- and 660-ton jacks
Result: Struts loaded to the required force and secured before the fixtures were moved to the next location
Shimmick Construction needed a reliable way to load the large horizontal steel struts supporting a deep foundation excavation in downtown San Francisco.
Because the excavation was surrounded by high-rise buildings, the temporary support system had to withstand substantial forces while helping control movement around the jobsite. Having worked with CH Bull on previous high-tonnage jacking projects, Shimmick contacted the team to develop a specialized hydraulic solution.
The Challenge
Large-diameter steel struts were installed at three levels of the excavation to support the surrounding walls. These struts needed to handle forces reaching up to 700 tons.
The contractor required a system that could apply a predetermined load accurately, hold each strut in position, and then be reused throughout the excavation. The equipment also needed to be practical to move between struts within a crowded downtown construction site.
Engineering the Jacking System
Bull high-tonnage jacking specialist Stan Sheppard worked with Shimmick’s engineers to design custom fixtures that fit around the large steel pipes.
The system included:
- Four 355-ton jacks with 4-inch strokes
- Four 660-ton jacks with 3-inch strokes
- Four 660-ton jacks with 6-inch strokes
- Hydraulic hoses, manifolds, valves, and gauges
- Two 10-horsepower pumps with 20-gallon reservoirs
Each jack was calibrated to its gauge so the contractor could accurately monitor the force applied to the struts.
The CH Bull Solution
The hydraulic jacks were mounted inside custom fixtures positioned around each pipe. Crews used the system to load the strut to the specified force before securing it in place.
Once a strut was set, the pressure was released and the fixture could be lifted by crane and moved to the next location. This reusable configuration allowed the contractor to work efficiently across the different struts and excavation levels.
Stan Sheppard also provided onsite consultation to help ensure the systems were assembled and operated correctly.
Project Outcome
The custom hydraulic system gave Shimmick Construction a controlled and repeatable way to preload the excavation struts.
By combining high-capacity calibrated jacks, reusable fixtures, and onsite technical support, CH Bull helped the contractor apply the required forces accurately and move the equipment efficiently from one strut to the next.
Need a Custom High-Tonnage Jacking System?
CH Bull supplies hydraulic jacks, pumps, manifolds, controls, custom fixtures, and complete equipment packages for structural support, load testing, lifting, and controlled positioning applications.