Engineers: attaching trail to Highway 82 at Shale Bluffs is feasible only with high risk and cost; boards favor pausing work

An engineering feasibility review presented June 3 to a joint session of the Pitkin County Board of County Commissioners and the Open Space & Trails Board found that directly attaching a trail to multiple Highway 82 bridges and retaining walls at Shale Bluffs is technically possible only with substantial additional investigation, very high construction risk and sharply higher costs.

SGM engineers said two reinforced concrete box culverts (the wildlife underpass and the Owl Creek culvert) could be extended to carry trail decking, and some bridge piers and abutments might accept independently framed attachments. But SGM cautioned that much of the 82 corridor there is lined by mechanically stabilized earth (MSE) walls and post-tensioned retaining structures whose facings and internal tendons cannot safely accept new loads without invasive work. Engineers described high-risk options that would require deep foundations, soil nails, specialty contractors and prolonged lane closures on Highway 82.

The firm estimated conceptual…