Design and Construction of Welded Wire Retaining Walls in the Siuslaw and Willamette National Forests

Major winter storms occasionally remove portions of the steep mountainous roads within the Siuslaw and Willamette National Forests of western Oregon. On average, at least one flexible welded wire reinforced wall is built a year in these forests to reestablish the failed roadway. This paper summarizes the procedures used for foundation investigation, analysis and design, and construction administration of welded wire reinforced retaining walls in these forests. Since 2005, the U.S. Department of Agriculture Forest Service has designed the walls according to the current AASHTO LRFD Bridge Design Specifications. The two forests follow AASHTO procedures with some modifications. These modifications include a narrower bench width at the toe of the wall, less conservative global stability resistance factors, no performance of settlement analysis, and stricter fill requirements for reinforced walls.