Corrugated steel pipe & plate has dominated the culvert application market since its emergence in the construction industry more than 100 years ago. Corrugated steel culverts, storm drains and sub drains are vital to the protection of streets, highways and railroads.
As the need for cost-effective, durable infrastructure has grown over the years, the corrugated pipe industry has responded.
Technological advancements provide more hydraulically efficient profiles and highly durable coatings, such as spiral rib pipe, polymer coatings, aluminized Type 2 steel and 2-ounce galvanized.
Corrugated steel pipe & plate culverts provide reliable, economical solutions to handle the flow, including debris, with minimum damage to the slope or culvert barrel.
Strength of Steel
Corrugated steel culverts maintain the advantage of the strength of steel with a variety of coatings providing long service life. With allowable fill heights over 100 feet and minimum covers as low as 12 feet, corrugated steel pipes & plates can be matched to the strength required. Established long-term materials properties ensure product performance throughout the design life.
| AISI-1 | ||||||
| Height of Cover Limits for Steel Pipe H20 or H25 Live Load • 2-2/3 x 1/2 Corrugation | ||||||
| Diameter or Span, in. | Min.* Cover, in. | Maximum cover (ft) for Specified Thickness (in.) | ||||
| 0.064 | 0.079 | 0.109 | 0.138 | 0.168 | ||
| 12 15 18 21 24 30 36 42 48 54 60 66 72 78 84 90 96 | 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 | 248 198 165 141 124 99 83 71 62 (53) | 310 148 206 177 155 124 103 88 77 67 (57) | 248 217 173 145 124 108 94 80 68 (57) (48) (40) (32) | 186 159 139 122 104 88 75 63 52 43 35 | 195 171 150 128 109 93 79 66 54 45 |
| Notes: 1. Fill heights in parentheses require standard trench installations; all others my be embankment or trench.2. In 12 in. through 36 in. diameter, heavier gages may be available – check with the manufacturer.* Minimum covers are measured from top of pipe to bottom of flexible pavement or top of pipe to top of rigid pavement. Minimum covers must be maintained in unpaved traffic areas. | ||||||
“Real” Manning N-Values | |
| Spiral Rib CSP | .012 |
| Double Wall | .012 |
| Concrete-Lined CSP | .012 |
| Fully Paved cSP | .012 |
| 2-2⁄3 x 1/2 Helical | |
| 12″ | .011 |
| 15″ | .012 |
| 18″ | .013 |
| 24″ | .015 |
| 30″ | .017 |
| 36″ | .018 |
| 42″ | .019 |
| 48″ | .020 |
| 54″ and larger | .021 |
Superior Hydraulics
Corrugated steel pipe & plate provides “smooth” alternatives and fabricated fittings for superior hydraulics. Spiral rib pipe and fully lined CSP have the lowest Manning n-values of any storm sewer material. Small diameter helical CSP also has very low roughness coefficients as proven through independent testing. Fabricated fittings provide superior hydraulics by minimizing energy losses at junctions.
Durability of Coatings
These factors, along with a variety of coating systems, mean CSP can meet any service life requirement. Galvanized, aluminized and polymer-coated CSP are just a few of the coating options. Expected service life can be determined using the NCSPA Service Life Guidelines.
Cost and Installation Advantages
Corrugated steel pipe & plate provides the lowest installed cost compared to other materials. This is due to the low up-front material costs plus the added advantages of reduced installation costs, especially in large diameters. CSP is one-tenth the weight of reinforced concrete pipe (RCP) and comes in lengths of 20 feet or longer. Add this to fewer joints and easy, positive connections and it equals an installation cost advantage.
For more information on the advantages of steel in construction visit our friends at the American Iron & Steel Institute.