LOS ANGELES - OUTFALL SEWER
OWNER: City of Los Angeles
LOCATION: Los Angeles, CA
VALUE: $257 Million
This contract was the largest public works contract ever performed by the City of Los Angeles. Kenny acting as the onsite managing partner for the Joint Venture, has completed the mining of the new interceptor system approximately 18.5 km-long (60,000 feet) with a primary support system of bolted, gasketed precast concrete segments in order to replace a portion of existing 70 year-old Los Angeles north outfall sewer. The project runs directly through central and south central Los Angeles and on into Culver City including under-crossings of several major freeways.
Lovat Tunnel Equipment of Canada supplied four 15.5 foot diameter EPBTBMs to the Kenny led consortium for excavating the 60,000 foot long tunnel under very tight schedule considerations. The four EPBM machines were specially designed to operate in EPB mode with a screw conveyor to bore through the predominantly soft ground and sandy soils in the Lakewood Formation and hard clay and soft rock in the San Pedro Formation. The tunnel was particularly risky in segments where the water table was well above the tunnel as it passed under the Los Angeles River with plenum pressures in excess of 1.5 bar and other areas that traversed an active oil field. All four machines utilized ground conditioning systems and EPB screws for spoil removal.
Three significant geological faults at Newport, Inglewood and Baldwin Hills were crossed with special concerns for previous seismic disruption so watertight construction techniques and primary lining were mandatory. The final lining was an 11 ft. inside diameter Ameron lined, prestressed concrete steel cylinder pipe installed in the previously mined segment lined tunnel and grouted in place. Over 1000 ft. of the eleven foot Ameron T-Lock lined pipe was repeatedly installed in a single heading in one shift.
The final lining was an 11 ft. inside diameter Ameron lined, prestressed concrete steel cylinder pipe installed in the previously mined segment lined tunnel and grouted in place. Over 1000 ft. of the eleven foot Ameron T-Lock lined pipe was repeatedly installed in a single heading in one shift.
The Project also included 8 shafts, 23 maintenance holes with 8 junction structures, a 275 foot long major four barrel tunnel siphon, 770 feet of micro-tunneling, and conduits for fiber optic cables installed along the entire alignment.
Of additional interest in this work was the SEM construction of the La Cieniga Siphon structure and shaft. Both shaft and siphon were constructed by SEM with shotcrete support. The main siphon tunnel was constructed with a crossectional area of 571 square feet and 154 feet long. More than 3,000 cubic yards of material was excavated in this complicated excavation. A further section was mined by SEM as a triple barrel siphon connecting the 11 foot diameter tunnels on each side.
The contract was originally scheduled to be placed in service in January of 2004, but was extended to a sewer in service date of June, 2004. Project delays were due to an archeological discovery and easement problems extended the contract completion.