ENGLISH – In mid-2020, bridge inspectors with the Hoosier National Forest noticed a problem. Steel supports under one of three bridges on the Hemlock Cliffs Trail was beginning to show signs of surface rust. While not structurally compromised, this early sign of wear indicated that the bridge would eventually need to be replaced.
The height and length of the existing bridge posed an additional problem. The base sat only a few feet above the streambed. Though infrequent, floodwaters from the stream could reach, or even overtake, the bridge’s walking surface. To solve this, engineering staff from the Forest Service’s Eastern Regional Office proposed a new bridge design. Steel beams were replaced with a stronger, longer-lasting glulam support structure. Glulam is a unique material composed of wood laminations bonded with strong, moisture-resistant adhesive. This material is well suited for a bridge over an intermittent stream.
With approximately $125,000 in funding provided by the Great American Outdoors Act, the bridge was recently replaced and a section of the trail was enhanced by a contracted crew from the Kentucky area. The new bridge has a higher clearance to allow water or debris to safely pass below it. It is longer to accommodate the clearance, with sturdy stone abutments included in the new construction.
To accommodate the construction of the bridge, a set of stairs was removed to allow equipment access. In addition to the new bridge, the staircase was rebuilt and another staircase was added to improve an area of the trail that had become incised from heavy use and was badly eroded. The new stairs are framed with wood and filled with crushed limestone aggregate for a sustainable, non-slip surface to improve safety.
In addition, approximately 2,000 feet of the trail used as the access route was resurfaced with crushed limestone aggregate, bringing the trail from 6 to 7 feet wide to 3 to 4 feet wide. The sides were seeded to allow natural vegetation to reclaim the exposed soil, and nearly 50 drainage structures were installed along the trail to prevent erosion or pooling of water, increasing the sustainability of this popular hiking trail.
The one-mile Hemlock Cliffs Trail is located between state roads 237 and 37 about 2 miles north of Interstate 64 in Crawford County, Indiana. The trail leads visitors through a unique box canyon. For more information visit http://bit.ly/44sfKka.
