Forell | Elsesser provided an innovative and cost-effective solution for a critical piece of Bay Area water infrastructure. Customized Solution

• The Mokelumne #3 Aqueduct is a 10-mile, 7.5-foot diameter steel pipeline that transports water between the towns of Holt and Bixler, California for the East Bay Municipal Utility District.  The pipeline is one of three aqueducts considered to be seismically vulnerable and is considered to be a critical lifeline facility.  The aqueduct segment is supported above the marshy Sacramento River Delta terrain on precast pile foundations for most of its length. Forell | Elsesser Engineers assisted prime consultant CH2M Hill in providing seismic protection design, including the use of elastomeric seismic isolation bearings for passive energy dissipation.
• One representative example of such an application is our execution of a scheme to protect a major water supply aqueduct to the East Bay region of Northern California.  Coincidentally, the water utility district (EBMUD) brought our firm into the process to improve on a scheme previously designed by CH2M Hill.  Our scheme involved the use of lead-rubber isolation bearing as an energy dissipator/soft horizontal restraint for a 7.5’ diameter aqueduct, extending approximately 10 miles across the “Delta” region of California.  The design accounted for the tolerance of the pipeline itself.  The use of this approach eliminated the need to strengthen the foundation substructure, which would have been practically impossible due to wetland preservation considerations.  It was found that the pipeline was sufficiently tolerant to distortion to allow significant motions in the supporting framework.  The higher movements allowed by this unconventional approach lowered seismic forces and saved money over CH2M Hill’s conventional bracing approach.

• Client: CH2MHill
• Owner: East Bay Municipal Utility District