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City Trunk Line South

Site supervision for SEM/NATM works
Estimated cost: Commencement:
July 01, 2016
Completion date:
November 01, 2016
111 Hope St
Los Angeles, CA 90012
United States
Technical data:
Geology description:

Wash deposits consisting of moderately dense sand, silty sands and sandy silts.

Bid cost: Final cost:
$14.5 million USD
Service areas:
Construction methods:

The constructed tunnel is part of the City Trunk Line project in L.A. (replacement of an existing water trunk line). The tunnel is located at the junction of Riverside Drive and Whitsett Avenue. It is between eight and ten feet in diameter and has a total length of 252 feet. To fit between the existing structures in the ground (foundation piles of a bridge), the tunnel follows an S-shape and is divided into sections with different geometries. The tunnel was built using NATM/SEM construction methods. The primary support measures included fibre reinforced shotcrete, lattice girders and spiles (rebar spiles and grouted pipe spiles).

South shaft
Completed tunnel section