Compare the two 8.5 foot diameter metal culverts with a Monolithic Bridge section. The two will carry about the same amount of water. The bridge will last eons longer, carry more load, and allow more trash to pass. And the bridge with sloped ends is far easier to maintain and will generally be less costly.
Generally, Monolithic Bridges are constructed to meet the building code for highways and bridges as written by AASHTO (American Association of State Highway and Transportation Officials). The heaviest loading for a short-span bridge is designated as HS 20-44. The AASHTO code showing this loading is included.












