Wednesday, November 9, 2011
The Whistle Stop Bridge, currently under construction, is a cooperative venture between the US Forest Service and the Alaska Railroad to make the Alaskan backcountry more accessible. This bridge is located along the Alaska railroad between Portage and Moose Pass, Alaska. The area is accessible to recreationists by a self-propelled rail car. The Glulam Bridge will span 282’ and cross the Placer River and when complete will be the longest clear-span timber bridge in North America.
The USFS solicited proposals and considered several design-build options but settled on a design submitted by Western Wood Structures through Patrick Engineering, a General Contractor from Denver, Colorado. To meet the Forest Service’s preference, the bridge design is a Camelback Truss style which is typical of many bridges built in the early 1900’s.
The bridge was pre-fabricated and trial assembled at our facility prior to pressure treatment. Due to its length, we could only pre-assemble three of the five 56’ sections at a time.
The bridge components were shipped to Anchorage by barge and railed to the site for final assembly. The installation scheme called for assembly to take place on either side of the river. Pinned connections were used in the bottom chord splices to facilitate assembly and erection.
Western Wood Structures furnished a superintendent to assist the Contractor in the truss assembly.
Ultimately, hikers will be able to safely cross the Placer River to access the spectacular Spencer Glacier and not be tempted to use the existing railroad trestle.