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Steel Structural Plate

ala1-1Steel sructural 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.  

DCP_1770_ArmtecThe 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

Range of Sizes
Common Uses
round.png 6 in. -51 ft
Culverts, subdrains, sewers, service
tunnels, etc. All plates same radius.
For medium and high fill (or trenches)
Vertical ellipse
5% nominal
eclipse.png 4-21 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 Arch
pipearch.png Span 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.png Span 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).
arch.png Span 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 Ellipse
Horiz.png Span 
7-40 ft
Culverts, grade separations, sorm
sewers, tunnels (structural plate).
pear.png Span
25-30 ft
Grade separations, culverts, storm
sewer, tunnels (structural plate).
High Profile 
highProf.png Span 
25-83 ft
Culverts, grade separations, storm
sewers and tunnels. Ammunition 
magazines, earth covered storage
(structural plate).
Low Profile 
lowProf.png Span
20-83 ft
Low-wide waterway enclosures,
culverts, storm sewers (structural plate).

For 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.

For more information on steel structural plate, check out the Corrugated Steel Pipe Design Manual or send us your questions through our Answer Desk.

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