Large Scale Use of DYWIDAG Anchors: The San Gabriel Trench in California

The San Gabriel Trench Project is being built in the city of San Gabriel in Los Angeles County. A 2.25km (1.4mi) long section of the Union Pacific railway tracks is being lowered into a trench that runs through the city.

The project includes four new road and pedestrian bridges crossing the tracks that will ensure a safe transit of the railway line for the almost 90,000 vehicles using the roads every day. Consequently, the long wait times and the ensuing environmental impact will be eliminated.

The trough structure is being built to a depth of 9.14m (30ft) and a width of 19.81m (65ft) using the open cut method. Once the excavation and stabilization measures have been finished, concrete walls will be erected in the trench, and the new railway tracks will be placed.

Different DYWIDAG Anchor Systems were required to stabilize the excavation walls. DSI Construction USA produced and supplied 202 temporary, 3-6 strand DYWIDAG Strand Anchors with a total length of approximately 13.3km (43,700ft) including accessories. Furthermore, 2,206 permanent, double corrosion protection (DCP) 4-10 strand DYWIDAG Strand Anchors were installed in the excavation. The permanent anchors utilize 0.6" strand with a total length of nearly 229km (751,000ft) as well as corresponding accessories.

DSI also produced and supplied 433 permanent, double corrosion protected (DCP) DYWIDAG Bar Anchors including accessories. More than 5km (16,700ft) of 26mm Ø, GR 150 DYWIDAG THREADBAR® was used for the bar anchors.

Furthermore, DSI supplied the equipment for testing and stressing the strand and bar anchors. The Tensa and HOZ type jacks ensured efficient and fast tensioning and a time-optimized lock off of the anchors.


Alameda Corridor-East Construction Authority (ACE), USA

General Contractor

Walsh Construction Co., USA


Malcolm Drilling Company, Inc., USA

Consulting Engineers

Moffat & Nichol, Pirooz Barar & Associates, Inc. (PB&A), BMA Construction Engineers, Inc., all of them USA

DSI Unit

DYWIDAG-Systems International USA Inc., BU Geotechnics, USA

DSI Scope

Production, supply

DYWIDAG Products

202 temporary, 3-6 Type 0.6" strand DYWIDAG Strand Anchors, 2,206 permanent, 4-10 Type 0.6" strand, DCP DYWIDAG Strand Anchors, 433 permanent, 26mm Ø DCP DYWIDAG Bar Anchors

Back More Projects
DSI Canada Civil Ltd.

use our contact form
send us an e-mail
or call us:
+1-905-888 8988