With notice to proceed scheduled for October 1 2000, the bid cycle is currently under way for the construction contract on the $220-$250m, 18km long, 2-4m diameter Los Angeles East-Central Interceptor Sewer (ECIS).
Tunnel construction, slated for a mid-2001 start, will be split into four main sections driven by four TBMs. Client the City of Los Angeles has stipulated that the machines must be slurry and/or EPB type, the choice of manufacturer being up to the successful contractor. The current schedule envisages contractor mobilisation in October 2000. This includes fabrication of the first two TBMs, one at shaft site P and one at Grand Avenue shaft, with tunnelling on these drives to begin in September 2001.
The two other TBMs are scheduled for fabrication at Grand Avenue and Mission Road shafts in November 2000. Boring from the two shafts will begin in October 2001.
Tunnel alignment will be at depths of 15-30m through the Los Angeles recent alluvium deposits. Lining will comprise precast concrete segments erected in the TBM tail shield to provide support against anticipated unstable ground and groundwater infiltration.
The scheme, designed by the Bureau of Engineering of the City of Los Angeles with Parsons Brinckerhoff Quade and Douglas providing engineering support, begins an intense re-construction of the LA sewer system. This follows a ‘Cease and Desist Order’ issued by the California Regional Water Quality Control Board, which came after large sewage spills caused by the El Niño storms of 1998.
Two major projects form the majority of the upgrade, the ECIS and the planned 17km long Northeast Interceptor sewer (NEIS), which will eventually extend the existing North Outfall Sewer (NOS) that is currently stretched to capacity. The ECIS system has a government order to be operational by November 30 2003; the NEIS is to be completed a year later.
Related Files
Los Angeles East-Central Interceptor Sewer
