County Sanitation District No. 2 of Los Angeles County
— December 2025
Dr. Sauer & Partners performed temporary work design tasks, signed and sealed by our Engineer of Record.
Construction of a joint water pollution control plant (JWPCP) effluent outfall tunnel. Tunnel dimensions: 8 miles in length, with 18ft i.d. The project features the first use in the USA of post tensioning (PT) of the segmental lining. Up to 40% of the alignment will feature PT in order to maintain integrity as a result of internal pressure during pumping out operations.
Dr. Sauer & Partners designed an unreinforced tremie slab and a crane pad for the JWPCP shaft, a starter and tail tunnel to facilitate the TBM launch, a TBM jacking frame, slurry wall panels for tail tunnel end wall, and risk assessment as well as mitigation measures design for squeezing ground conditions of TBM drive.
The shaft is located in the Lakewood formation which primarily consists of fine sand with silt. The tunnel crosses various geologic formations including squeezing ground.
Los Angeles, USA