Switzerland
Switzerland

Cascade Mountain, US Highway 12

US-12, 98937, 48935 US-12, Naches, WA 98937
2017
Customer
Washington State Department of Transportation
Engineering
Washington State Department of Transportation
Contractor
Hi-Tech Rockfall Construction, Inc.
Protected object
Road
Corrosion protection
GEOBRUGG SUPERCOATING
Stabilized area
780 m²
Maximum slope height
25 m
Slope inclination
70 ° - 85 °
Exposition
-
Initial situation

US Highway 12 is the Southern most pass that crosses the Cascade Mountain in the state of Washington, USA.  Numerous slopes near White Pass are active rockfall areas.  They have been mitigated over the decades with many solutions including numerous draped mesh systems composed of traditional cable nets.  One such antiquated cable net drape at MP 152 was draped across a rockfall chute and in 2017 was destroyed by severe rock and snow slides.  The Washington Department of Transportation decided to update the system with the stronger and improved Rolled Cable Nets (S4-250).

Geology

White Pass Scenic Byway and was featured in Newell Campbell’s geologic road guide (1975) (Fig. H-1). The byway passes through one of the most scenic and geologically interesting areas in Washington. There are tens of volcanic centers that range in age from earliest Miocene to Pleistocene. Late Paleozoic/Mesozoic sedimentary rocks and metamorphic rocks, glacial deposits, and large active landslides are also exposed along the way. The Russell Ranch Formation is exposed near MP 148 along US 12. The Russell Ranch unit includes marine sedimentary and volcanic rocks that are at least in part of Late Jurassic and Early Cretaceous age (~145–130 Ma).  Numerous Quarternary landslide and talus Deposits are also 

From INFORMATION CIRCULAR 107 (Pringle, et al.)

Description

Geobrugg worked with the Washington Department of Transportation assisting them in creating a robust Rolled Cable Net drape. The updated drape included upsized and redundant support rope infrastructure. The support rope and flexible wire rope cable anchors were made of 1-1/8" ropes having 130 kip ultimate strength.  The Rolled Cable Nets (S4-250) being 30 % stronger than the nets being replaced were chosen as they performed well in another nearby installation. Hi-Tech Rockfall Construction, Inc. performed scaling at the site and quickly installed the large Rolled Cable Net panels.

Your local contact

Roger Moor
Roger Moor
Country Manager Ost- und Zentralschweiz, Liechtenstein
Natural Hazards, Coastal Erosion Protection, Mining / Tunnels
Geobrugg AG
Aachstrasse 11
8590 Romanshorn / Switzerland
René Müller
René Müller
Country Manager Kantone AG BE BL BS FR GE JU NE SO VD VS
Natural Hazards, Mining / Tunnels
Geobrugg AG
Industriestrasse 21
5200 Brugg / Switzerland
Isacco Toffoletto
Isacco Toffoletto
Ticino Country Manager
Natural Hazards, Mining / Tunnels
Geobrugg AG Ticino
Stabile Cometal, via Pizzante 7
6595 Riazzino / Switzerland