Steel Structural Plate

Steel structural plate consists of corrugated steel sections that are bolted together to form the required shape. The corrugated sections are commonly referred to as plates and have a standard corrugation profile of 6 x 2 inches that are formed perpendicular to the length of the culvert bridge.


Structural plate structures are specified where the pipe required exceeds the size that can be shipped to the job site, or where earth cover is so great that the wall thickness furnished by a shop-manufactured pipe will not meet design requirements.

Standard plates are fabricated in three lengths and several different widths. These plates are available in thicknesses from 0.222 inches to 0.380 inches. Plates are furnished curved to various radii and are clearly identified by the fabricator for field assembly. The fabricator provides assembly drawings to aid the installer.


The plates are assembled into various shapes as indicated in the table below. The shapes include round, pipe arch, singles-radius arch, horizontal ellipse, low profile arch, high profile arch, pear, underpass and vertical ellipse, special shapes, and other sizes of standard shapes beyond what is shown in the tables, are also available, The fabricator provides detailed assembly instructions with each structure.


The benefits of steel structural plate include:

  • Structural capacity
  • Lightweight construction
  • Easy installation
  • Aesthetically pleasing
  • Economical solutions
  • Design flexibility
Shapes and uses of corrugated steel  structural plate
ShapeRange of SizesCommon Uses
Roundround6 in. -51 ftCulverts, subdrains, sewers, service
tunnels, etc. All plates same radius.
For medium and high fill (or trenches)
Vertical ellipse
5% nominal
eclipse4-21 ft
nominal;before elongating
Culverts, sewers, service tunnels,
recovery tunnels. Plates of varying
radii;shop favbrication. For
appearance and hwhere backfill
compaction is only moderate.
Pipe ArchpipearchSpan x Rise 17 in, x 13 in.
20ft 7 in x
13 ft 2 in.
Where headroom is limited, Has
hydraulic advantages at low flows.
Corner plate radius. 18 inches or
31 inches for structural plate.
Underpass*underpassSpan x Rise
5ft 8 in, x 5 ft 9 in.
20 ft 4 in. x 17 ft 9 in.
For pedestrians, livestock or
/> vehicles (structural plate).
ArcharchSpan x Rise
5 ft x 1 ft 9 1/2 in.
82 ft x 42 ft
For low clearance large waterwway
openinng, and aesthetics (structural plate).
Horizontal EllipseHorizSpan
7-40 ft
Culverts, grade separations, sorm
sewers, tunnels (structural plate).
25-30 ft
Grade separations, culverts, storm
sewer, tunnels (structural plate).
High Profile
25-83 ft
Culverts, grade separations, storm
sewers and tunnels. Ammunition
magazines, earth covered storage
(structural plate).
Low Profile
20-83 ft
Low-wide waterway enclosures,
culverts, storm sewers (structural plate).
SpecialsVariousFor lining old structures or other
spcial puposes. Special fabrication.
Notes: *For equal area or clearance, the round shape is generally more economical and easier to assemble.