San Francisco Slip Joint Project Featured in ENR Magazine

Stress Engineering Services is featured in the June 30th edition cover story of Engineering News-Record magazine.  The article entitled “Water Pipeline Designed to Surf Seismic Waves,” is about the San Francisco Public Utilities Commission plans to upgrade a pair of water pipelines that cross the Hayward Fault in Fremont, CA.  This project is just one of 83 proposed projects that are part of the $4.7 billion water system improvement program happening throughout the San Francisco Bay Area.

It is expected that during an earthquake the Hayward Fault will shift by up to 6.5 feet in nearly 2 seconds.  The objective of this project was to come up with a multi-pronged approach to allow the pipeline to move and flex with the movement of the earth. As part of this challenge, Stress Engineering Services was asked to design, assemble, and test a slip joint that could handle 9 feet of compression in the pipeline during an earthquake.

The 77 ton slip joint is surrounded by 8 huge pressure balancing cylinders that contend with the normal water pressure in the pipeline.  The cylinders are what allow the slip joint to easily compress during seismic motion.

To read the full article and view the photo gallery, go to http://california.construction.com/california_construction_projects/2014/0708-Water-Pipeline-Designed-to-Surf-Seismic-Waves.asp