AS/NZS 2041: 1998 - Class 1 Flanged Nestable Pipe Arch - 68mm x 13mm
Markham Culverts produces in Lae Flanged Nestable profiles for
use in low headroom situations or where a flatter wider cross section is preferable.
The top section is basically a half circular pipe and the invert sections have corner radii pre formed in the plant.
Because the profile geometry concentrates the applied loads under the tight radius of the corners specific attention should be applied to foundations, particularly under the haunches.
The limiting factor of gauge selection in most cases is usually the ground bearing capability of the foundation under the haunches. Check the acceptable heights of cover from the table below.
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Nestable Pipe Arch - Heights of Cover for T44 Highway Loading |
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Internal Dimensions |
Steel thickness |
Minimum Cover |
Maximum Cover in metres for various Haunch Bearing Capacities |
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Max Span |
Rise |
End Area m2 | mm. | m. | 300 kPa | 600 kPa | 900 kPa | 1,000 kPa | |
| 450 mm | x | 340 mm | 0.12 | 1.6 mm | 0.60 m | 8.5 m | 16.9 m | 16.9 m | 16.9 m |
| 600 mm | x | 430 mm | 0.20 | 2.0 mm | 0.60 m | 6.2 m | 13.1 m | 17.0 m | 17.0 m |
| 750 mm | x | 510 mm | 0.30 | 2.0 mm | 0.60 m | 4.7 m | 10.4 m | 13.5 m | 13.5 m |
| 900 mm | x | 600 mm | 0.43 | 2.5 mm | 0.60 m | 3.7 m | 8.5 m | 13.1 m | 14.2 m |
| 1,050 mm | x | 680 mm | 0.57 | 2.5 mm | 0.60 m | 2.9 m | 7.2 m | 11.1 m | 12.1 m |
| 1,200 mm | x | 770 mm | 0.72 | 2.5 mm | 0.60 m | 2.3 m | 6.2 m | 9.7 m | 10.5 m |
| 1,350 mm | x | 860 mm | 0.91 | 2.5 mm | 0.60 m | 1.8 m | 5.4 m | 8.5 m | 9.3 m |
| 1,500 mm | x | 940 mm | 1.11 | 2.5 mm | 0.60 m | * | 4.7 m | 7.6 m | 8.3 m |
| 1,650 mm | x | 1,030 mm | 1.32 | 3.5 mm | 0.60 m | * | 4.2 m | 7.7 m | 7.7 m |
| 1,800 mm | x | 1,100 mm | 1.53 | 3.5 mm | 0.63 m | * | 3.7 m | 7.0 m | 7.0 m |
| 1,950 mm | x | 1,170 mm | 1.79 | 3.5 mm | 0.65 m | * | * | * | 6.0 m |
For a full listing refer to AS/NZS 2041:1998 Table E1.5 - (Highway) or E1.4 (Railway) live loads.
The stated heights of cover are applicable to structures correctly installed fully in accordance with AS/NZS 2041:1998 bedding, installation and backfilling procedures.
Note: The 1950 x 1,170 mm Size is outside the published range of AS/NZS 2041, if specified, additional supervision of the backfilling is recommended.
