Abstract: A load bearing arch is disclosed, including a lower arch and an upper arch separated by a first beam and a second beam. Interior foam is provided between the lower arch and the upper arch, and a tension cable extends above the lower arch and between the first beam and the second beam. One or more levelling plates are positioned at a top of the upper arch. One or more plate ties extend vertically between the lower arch and the upper arch.

Abstract: A natural bottom culvert and installation method that preserves the in-stream environment for fish to spawn, forage and migrate, while being able to withstand high-water levels. The culvert has an arch-shaped member that is placed over the stream in connection with elongate footings placed on terraces prepared on each stream bank. The footings have a plurality of apertures spaced along their elongate dimensions. Anchor posts are driven into the terraces through the apertures and affixed to the footings. Fill material is placed over this assembly and a road is constructed over the fill material.