Tunnel Ribs
Used for support of new tunnels and excavation in both soft and hard rock tunnels. Circular in profile, comprised of cold-formed or rolled Wide-Flange Beams cut into segments and bolted together in the field. Spaced with tie rods and/or pipe spacers, typically on 4 or 5 centers. Often lagged with mixed-hardwood or channel lagging to carry loads between ribs and provide TBM thrust support during mining operations. Coating are typically hot dipped galvanization.