corrugated steel pipe 6

https://atomic-wiki.win/index.php/Understanding_Corrugated_Steel_Plate_for_Culvert_and_Drainage_Applications

Corrugated steel pipe is a familiar sight in drainage ditches and under roadways, its distinctive ribbed design giving it strength without being overly heavy. I remember watching crews install sections of it during a highway expansion, each piece fitting snugly into the next to create a durable channel for stormwater. The galvanized coating helps it resist rust, so it can last for decades buried in the earth, handling heavy loads and constant water flow.