Placer River Trail Bridge is now complete

The Forest Service has built the longest clear span, glue laminate, timber truss bridge in North America. As part of the Chugach National Forest Whistle Stop Project, contractors are assembling two 112-foot sections on either side of the Placer River near the current Spencer Glacier Whistlestop.

This Placer River Trail Bridge serves as critical linkage between the Spencer and Grandview Whistle Stops. When complete the Project will including over 30 miles of trails connected five Whistle Stops, cabins and campsites.

The Whistlestop project is allowing the average person to visit and enjoy backcountry normally only available to experienced and well-equipped recreationists.

Here is a list of interesting facts:

Placer River Trail Bridge Facts

  • The Placer River Trail Bridge is a pedestrian bridge that serves as a critical link connecting all existing and proposed Whistle Stops by trail. It is not intended for bicycle or motorized access.

  • Site work began in the late summer/early fall of 2010 with the subsurface (geotechnical) investigation required for foundation design. Fabrication began in the spring of 2011 with deliveries and construction commencing in June 2011.The bridge was completed was 24 July 2013.

  • Overall clear-span length: 280 feet

  • Overall width: 14 feet, 10 ¾ inches, with a 6 foot wide walkway

  • The top of the bridge to the water level is approximately 50 feet with 20 feet of clearance from the water and about 30 feet of total bridge height in the center of the span. The bridge was designed with enough clearance to ensure that any ice bergs coming down stream during periods of high flow would pass freely under the bridge. The bridge is located 900 feet upstream of the steel railroad bridge.

  • The bridge can support 90 pounds per square foot of pedestrian load.

  • It is equipped to withstand numerous environmental stresses resulting from: wind gusts up to 120mph, 200 pounds per square foot of ground snow load, flooding potential, and high seismic events.

  • The deck panels, posts, cap rail and horizontal rail elements (with the exception of the graspable rail) are made of Alaska Yellow Cedar (AYC) glulam*. Graspable rail is standard AYC (non-glulam). No preservative is needed on these areas of pedestrian contact, due to the decay-resistant nature of the wood. Preservative-treated Douglas Fir glulam was used for the truss members, floor beams, purlins, and all bracing members. (*Glulam, or glued-laminated timber, is an engineered wood product comprising a number of layers of dimensioned timber bonded together with durable, moisture-resistant structural adhesives.)

  • The bridge cost $1.67 million and was funded through the American Recovery and Reinvestment Act (ARRA).

  • The contract was a design/build contract awarded to Patrick Albin Carlson, a Joint Venture, Denver, CO.  They subcontracted the bridge design and fabrication to Western Wood Structures, Tualatin, OR.

See some photos of the construction project by clicking here