PRECAST
CONCRETE
CULVERTS
Aveng Manufacturing Infraset
S-Class culverts bear the
SABS mark and are designed,
manufactured and tested in
accordance with SANS 986.
Technical Data
Introduction
Aveng Manufacturing Infraset design and
manufacture high quality, high performance factory
engineered precast concrete culverts for use in
a wide range of modern construction and civil
engineering projects.
The company expertise combined with modern
manufacturing facilities and years of experience
enables Aveng Manufacturing Infraset to offer an
extensive range of standard culverts as well as the
manufacturing of non standard, project specific
culverts.
In addition to their exceptional load bearing
capabilities and structural stability, precast concrete
culverts require very little or no maintenance at all
to exceed the useful life.
CLASSIFICATION OF CULVERTS
Types of culverts
Aveng Manufacturing Infraset offers the full range
of S-Class rectangular portal culverts readily
available in lengths of 1.2m. Culverts ranging in
size from 450mm x 450mm up to 3600mm x 3000mm
with Butt-joints are manufactured to the relevant
S-Class strength requirements. All S-Class portal
culverts bear the SANS mark and are designed,
manufactured and tested in accordance with SANS
986:2006: Precast reinforced concrete culverts.
Reinforced concrete bases are available for all
S-Class culverts and are easily installed on site to
complete a structurally stable engineered unit.
SAR rectangular portal culverts manufactured to
Spoornet loading, NR 1983, have thicker deck and
leg sections to accommodate larger fill heights
and imposed loads. Culverts ranging in sizes from
900mm x 450mm up to 3000mm x 3000mm are
manufactured and unit lengths ranging from 1.2m
up to 1.5m as stated in the product tables. SAR
culverts are available in 2 strength classes, 0-5m fill
and 5-10m fill. Reinforced concrete bases are
available for SAR culverts being placed where the
fill height does not exceed a maximum of 5m.
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Ribbed skew haunch culverts are designed and
manufactured to withstand C-Class loading conditions,
consisting of a vertical proof load of 150kN/m and
a horizontal proof load of 30kN/m. Ribbed culverts
range in size from 600mm x 450mm up to 3000mm
x 3000mm and vary in unit length as shown in the
product tables.
Aveng Manufacturing Infraset also manufacture
jacking box culverts in various sizes and in standard
lengths of 1.190m which are manufactured with bolt
holes for longitudinal ties.
Strength of culverts
Precast portal culverts are classified in terms of their
crushing strength when subjected to a combination of
loading cases involving vertical and horizontal knife
edge tests conducted under factory conditions. The
proof load test can be defined as a line load that a
culvert must resist without the development of crack
widths exceeding 0.25mm over a length of 300mm
or over two adjacent ribs in ribbed 16 culverts. When
required, ultimate load test are also carried out to a
magnitude of 25% greater than the applicable proof
loads.
There are three different loading configurations that
are applied to precast portal culverts to simulate
the installed conditions, namely the deck bending
moment, deck shear and the inner leg bending moment.
The inner leg bending moment is only taken into
consideration for the S-Class portal culverts.
Loads on culverts
S-Class portal culverts are tested to a vertical proof
load which is a function of the strength class multiplied
by the span of the culvert, a horizontal proof load of
30kN/m applied to the top of the leg and a horizontal
leg load applied at a height 0.2 times the height of
the leg measured from the bottom of the leg for
culverts with a height to span ration of more that 0.5.
The horizontal leg load is determined by the vertical
load multiplied by the relevant factor.
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Technical Data
Load classifications
Installation conditions
Culvert
Span
Culvert
Class
Vertical
Proof Load
(kN/m)
Horizontal
Proof Load
(kN/m)
Horizontal Leg
Load Factor
Span > Height
Horizontal Leg
Load Factor
Span = Height
450
600
750
900
1200
1500
1800
2100
2400
3000
3600
200
200
175
175
150
100
75
75
75
75
75
200 x 0.450
200 x 0.600
175 x 0.750
175 x 0.900
150 x 1.200
100 x 1.500
75 x 1.800
75 x 2.100
75 x 2.400
75 x 3.000
75 x 3.600
30
30
30
30
30
30
30
30
30
30
30
0.2
0.2
0.2
0.2
0.2
0.3
0.4
0.4
0.4
0.4
0.4
0.45
0.45
0.4
0.4
0.4
0.5
0.6
0.6
0.6
0.6
0.6
The trench condition occurs when the culvert is placed into a trench cut into natural ground and then backfilled with suitable material.
Example
A 1200 x 1200 150S Culvert must resist
Trenched Installation
Vertical
Proof load = 150x1.200 =180 kN/m
Ultimate load = 180 x 1.25 = 225 kN/m
Horizontal
Proof load = 30 kN/m
Ultimate load = 30 x 1.25 = 38 kN/m
Leg load (Span = Height)
Proof load = 180 x 0.4 = 72 kN/m
Ultimate load = 72 x 1.25 = 90 kN/m
SAR portal culverts are manufactured for installations under
railway track and designed to take account of train track, ballast
and backfill load combinations as stated in the Spoornet Loading
code of practice: NR 1983.
The fill height above the culvert, determines the strength class
of the culverts. All SAR culverts are available in two strength
classes to suit either 0-5m or 5-10m fill height conditions.
In the embankment condition the culvert is installed at ground level and is backfilled with suitable material.
Embankment installation
Culvert in precast base configuration
Temporary prop arrangement
Note: For H>1.5m, provide horizontal props
at 40% height above base during backfilling
and compaction. One prop per precast
concrete unit.
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