Best Small Project: Catwalk Trail Reconstruction Design-Build
Catwalk Trail Reconstruction
Owner/Developer: Federal Highway Administration, Central Federal Lands Highway Division
Design Firm: Bohannan Huston Inc.
General Contractor: AUI Inc.
Civil/Structural Engineer: Bohannan Huston
Geotechnical Engineer: NV5
Subcontractors: Saguaro GeoServices Inc.; Kimo Constructors Inc.; Franklin Drilling & Blasting; Southwest Concrete & Paving Inc.
For nearly 85 years, the Catwalk Trail in the Gila National Forest of southwestern New Mexico was considered one of the state’s special jewels and was designated a National Recreation Trail in 1978.
In 2013, a heavy rainstorm flooded Whitewater Canyon, destroying the historic catwalk. A fire in 2012 charred the landscape, leaving the area more vulnerable to flooding.
The parameters of the trail’s rebuild included the design and construction of three steel bridges along with 700 ft of suspended catwalk in a remote slot canyon.
Workers restored primitive trails leading to the bridges, removed creek obstructions and flood-damaged structures, and rehabilitated and expanded a nearby parking lot while preserving historical and archaeological elements.
Due to the complex facets of the slot canyon walls, the project team used light detection and ranging (LiDAR) scanning, supplemented by a conventional ground survey, to accurately capture every nook and cranny of the canyon in a dense, 3D mesh made up of millions of survey points. According to the construction team, mapping the canyon was critical to the project’s success because it allowed designers to locate with pinpoint accuracy where the support beams should be placed in the canyon walls and thereby minimize potential construction delays.
The new structure is a cantilever beam-supported catwalk that embraces the historical vision of floating above the canyon floor while functionally avoiding debris-catching structural elements.
Scanning, surveying and modeling also provided the necessary level of accurate data to design and establish the height of the catwalk above the creek floor to minimize the risk of future flood damage. Site conditions led to a unique solution on marking beam placements: driving rebar into the canyon walls and bending it to match the required bearings.
Contractor AUI completed weekly safety inspections and used the Associated Builders and Contractors’ CLAS Partnership Agreement with the New Mexico Occupational Health and Safety Bureau to conduct joint safety inspections.
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