CGI Corrugated Technical Information

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Material specifications

CGI is made from high tensile steel for strength and impact resistance. It is available in long lengths for added life and enhanced appearance. It has a non-syphoning side lap which reduces the risk of moisture transfer between sheets due to capillary action, thus reducing the risk of roof leakage. CGI is available in un-painted zinc/alum, and in an attractive range of factory pre-painted colours.

Material Specifications
Material Properties Finish 0.35 BMT 0.42 BMT 0.48 BMT
Total Coated Thickness (TCT) mm Zinc/alum 0.40 0.47 0.53
Colour 0.43 0.50 0.56
Mass (kg / linear metre) Zinc/alum 2.74 3.26 3.70
Colour 2.79 3.32 3.76
Mass (kg / square metre) Zinc/alum 3.60 4.28 4.86
Colour 3.67 4.35 4.93
Yield (square metre / tonne) Zinc/alum 277.9 233.8 205.9
Colour 272.3 229.8 202.8
Tensile Strength (MPa) Zinc/alum & Colour 550 550 550
Width Coverage (mm) Zinc/alum & Colour 762 762 762
Sheet Tolerances (mm) Length & Width ±5 ±2 ±5 ±2 ±5 ±2
Minimum Roof Pitch Zinc/alum & Colour N/A 5° 5°

Compliance

The Wind Capacity Tables are based on testing in accordance with AS1562.1-1992 and AS4040.0, 1 & 2- 1992. Span tables have been developed by determining wind pressures in accordance with AS4055-2006 for domestic applications and AS/NZS 1170.2:2002 for all other applications. Capacity tables are in limit state format.

Spans

Spans are determined by wind speeds for non-cyclonic areas. For domestic applications, the pressures and spans are based on a maximum: eaves height of six metres, roof pitch of 35 degrees and total roof height of 8.5 metres. For commercial and industrial applications, tables are based on a maximum overall height of ten metres and a 500 year design return period.



Roofing calculations are based on Cpe=-0.9 and Cpi=0.2, walling is based on Cpe=-0.65 and Cpi=0.2. A local pressure factor, Kl=2.0 has been used for all roofing and walling spans for both strength and serviceability limit states. Roof spans allow for loads incidental to maintenance.

All pressures have been determined assuming the wind loading in any direction is not affected by topography. The following shielding factors have been used for each of the terrain categories: Category 3 = 0.85, Category 2.5 = 0.95, and Category 2 = 1.

The carport and verandah spans only apply to structures not enclosed by peripheral walls. Spans are based on Cpn=-0.9 and Kl=1.5 applied over the entire span, and are suitable for all span types. Loads on supporting purlins may limit these spans.

Stratco can provide additional engineering advice if any design parameters vary from those above.

Wind Load Conversion

For domestic applications use the appropriate wind classification for the area. To read the span tables for commercial and industrial applications, select the region and category for the area, then convert it to the correct classification using table 2.0 below.

Wind Load Conversion
Wind Classification (Domestic) Region & Category (Commercial / Industrial)
N1 (W28) Reg A, Cat 3
N2 (W33) Reg A, Cat 2.5 - Reg B, Cat 3
N3 (W41) Reg A, Cat 2 - Reg B, Cat 2.5
N4 (W50) Reg B, Cat 2

Maximum Recommended Spans

Maximum Recommended Spans (mm)
Span Type Roofing (BMT) Walling (BMT)
0.42 mm 0.48 mm 0.35 mm 0.42 mm 0.48 mm
Single Span 800 900 1300 1650 1900
End Span 950 1300 1750 2100 2250
Internal Span 1200 1800 2300 2700 2800
Un-stiffened Overhang 200 250 150 200 250
Stiffened Overhang 300 350 250 300 350

Roofing spans are limited, based on typical maintenance foot traffic. Walling spans are based on N1 (W28) wind loading. Spans are based on three fasteners per sheet, per support. The values are for use with steel supports with a minimum thickness of 0.75mm, G550.

Domestic Carport / Verandah Spans

Domestic Carport / Verandah Spans (mm)
Wind Classification Base Metal Thickness
0.42 mm 0.48 mm
N1 (W28) 1700 2000
N2 (W33) 1700 2000
N3 (W41) 1450 1600
N4 (W50) 1050 1050

The values are for use with steel supports with a minimum thickness of 0.75mm, G550.

Spans

Spans (mm)
BMT Application Span Type Three Fasteners Five Fasteners
N1 (W28) N2 (W33) N3 (W41) N4 (W50) N1 (W28) N2 (W33) N3 (W41) N4 (W50)
0.35 mm Walling Single 1300 850 600 - 1650 1450 1250 1000
End 1750 1200 750 - 2050 1750 1450 1000
Internal 2300 1650 1100 - 2450 2200 1950 1600
0.42 mm Roofing Single 800 800 600 - 800 800 800 800
End 950 950 750 - 950 950 950 950
Internal 1200 1200 1050 - 1200 1200 1200 1200
Walling Single 1650 1350 1050 900 1700 1500 1350 1300
End 2100 1550 1100 1000 2200 1900 1500 1450
Internal 2700 2200 1700 1450 2700 2300 2050 1950
0.48 mm Roofing Single 900 900 600 - 900 900 900 900
End 1300 1300 1000 - 1300 1300 1300 1300
Internal 1800 1800 1550 - 1800 1800 1800 1750
Walling Single 1900 1450 1100 950 2100 1750 1450 1400
End 2250 1850 1500 1300 2250 1950 1700 1650
Internal 2800 2200 1950 1800 2800 2300 2100 2000

The values are for use with steel supports with a minimum thickness of 0.75mm, G550.

Wind Capacities

Wind Capacities (kPa)
BMT Span Type Limit State Span (mm) Three Fasteners Span (mm) Five Fasteners
600 900 1200 1500 1800 2100 2400 2700 3000 600 900 1200 1500 1800 2100 2400 2700 3000
0.35 mm Single Serviceability 1.25 0.88 0.64 0.55 0.45 0.37 0.29 0.21 - 3.22 2.04 1.36 0.91 0.45 0.37 0.29 0.21 -
Strength 3.12 2.55 2.10 1.80 1.50 1.20 0.90 0.65 - 4.86 3.93 3.03 2.68 2.33 2.04 1.75 1.46 -
End Serviceability 1.36 1.15 0.95 0.78 0.60 0.42 0.25 0.18 - 3.96 2.76 1.95 1.18 0.88 0.59 0.29 0.18 -
Strength 3.34 2.63 2.15 1.82 1.50 1.17 0.85 0.55 - 4.39 3.61 2.98 2.39 2.24 2.09 1.94 1.46 -
Internal Serviceability 1.57 1.38 1.19 1.00 0.86 0.71 0.57 0.43 - 4.26 3.15 2.51 1.91 1.50 1.09 0.68 0.45 -
Strength 4.12 3.38 2.80 2.35 1.95 1.55 1.15 0.94 - 6.09 5.15 4.26 3.56 3.00 2.44 1.88 1.73 -
0.42 mm Single Serviceability 1.73 1.40 1.09 0.78 0.46 0.40 0.34 0.27 - 4.68 2.82 1.64 1.00 0.45 0.39 0.33 0.27 -
Strength 5.07 3.60 2.65 2.10 1.80 1.56 1.38 1.11 - 7.41 6.27 5.25 4.26 3.27 2.86 2.46 2.06 -
End Serviceability 1.85 1.48 1.17 0.99 0.80 0.62 0.44 0.36 - 5.29 3.52 2.09 1.27 1.00 0.73 0.45 0.36 -
Strength 5.17 3.66 2.67 2.10 1.86 1.63 1.39 1.15 - 7.14 5.81 4.55 3.50 3.21 2.92 2.63 2.33 -
Internal Serviceability 1.94 1.75 1.54 1.36 1.18 1.00 0.81 0.63 - 5.70 3.86 2.67 1.97 1.59 1.20 0.82 0.64 -
Strength 5.87 4.75 3.80 3.48 3.15 2.83 2.50 1.88 - 7.64 6.37 5.43 5.03 4.64 4.25 3.86 2.33 -
0.48 mm Single Serviceability - 1.48 1.13 0.91 0.69 0.50 0.32 0.27 0.22 - - 1.88 1.18 0.89 0.62 0.35 0.29 0.23
Strength - 5.03 4.31 3.87 3.50 3.13 2.64 2.19 2.01 - - 6.62 5.85 5.25 4.67 4.08 3.35 2.63
End Serviceability - 1.74 1.47 1.23 0.98 0.74 0.50 0.39 0.27 - - 2.47 1.60 1.14 0.82 0.50 0.40 0.31
Strength - 4.90 4.22 3.85 3.50 3.14 2.65 2.22 1.77 - - 7.11 6.32 5.64 5.01 4.38 3.68 2.98
Internal Serviceability - 2.30 1.99 1.70 1.41 1.09 0.76 0.66 0.55 - - 3.76 2.53 1.72 1.27 0.83 0.67 0.52
Strength - 5.92 4.98 4.30 3.75 3.21 2.66 2.23 1.80 - - 8.28 6.89 5.96 5.25 4.54 3.78 3.02

The values are for use with steel supports with a minimum thickness of 0.75mm, G550.

Water Carrying Capacity

Maximum Roof Run For Drainage (m)
Roof Slope Peak Rainfall Intensity (mm / hr)
150 180 200 250 300 350 400 450
5° 27 23 20 16 13 11 10 9
7.5° 34 28 25 20 17 14 12 11
10° 39 32 29 23 19 10 14 13
15° 48 40 36 29 24 20 18 16
22° 59 49 44 35 29 25 22 19
30° 71 59 53 42 35 30 26 23

The peak rainfall intensities shown represent a 100 year average recurrence interval (ARI) for a five minute rainfall duration. If roof penetrations exist, the total roof run will generally be greater than the distance from ridge to eaves at the location the penetration interferes with the runoff. Contact Stratco if further advice is required.