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Department of Public Works | James Cook University
REPORT NO. TS776
Simulated Wind Driven Debris Impact
Testing of Corrugated Roof Cladding
3 September 2010
By Ulrich Frye
Cyclone Testing Station
School of Engineering and Physical Sciences
James Cook University
for Queensland Government
Department of Public Works
GPO Box 2457, Brisbane, QLD 4001
Disaster Preparedness
Department of Public Works
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1 Introduction
In this testing program, simulated wind driven debris impact loading of corrugated roof cladding to be
installed on public cyclone shelters in Queensland was performed. The cladding was loaded in accordance
with the Design Guidelines for Queensland Public Cyclone Shelters, Sep 2006. The testing was performed
with the use of new test materials, purchased from a local supplier. All tests were conducted in the air
cannon testing facility located at James Cook University.
2 Design Guidelines for Debris Loads
The structural design guidelines for debris loads state that the external fabric of public cyclone shelters is
to be at least capable of resisting wind debris defined as:
a) Five spherical steel balls of 2 grams mass and 8 mm diameter impacting at 0.4 x V10,000 for
horizontal trajectories and 0.3 x V10,000 for vertical trajectories.
b) A 100 mm x 50 mm piece of timber of 4 kg mass impacting end-on at 0.4 x V10,000 for horizontal
trajectories and 0.1 x V10,000 for vertical trajectories.
In Queensland’s tropical cyclone region (Region C) V10,000 = 85 m/s. Thus, the required impact speeds are:
0.1 x V10,000 = 8.5 m/s
0.3 x V10,000 = 25.5 m/s
0.4 x V10,000 = 34.0 m/s
3 Test Criteria and Procedures
3.1 Test Loads
For Cyclonic Regions C the debris test loads for the external fabric of public cyclone shelters are specified
as follows:
• Test Load A: End-on impact of timber 4 kg in mass, with cross-section dimensions of 100 mm x 50 mm,
impacting at the speed specified for the trajectory.
• Test Load B: Series of five steel balls of 2 grams mass and 8 mm diameter, successively impacting at the
speed specified for the trajectory.
3.2 Test Sequence
A test specimen shall be subject to successive test loads applied in the following order:
1) Debris Test Load A
2) Debris Test Load B
Test load A shall impact the most critical location(s). The testing authority shall determine the most critical
location(s) by test. Test load B shall successively impact at various random locations on the test specimen.
3.3 Acceptance Criteria
A test specimen shall:
a) Prevent a debris missile from penetrating through
b) If perforated, have a maximum perforation width of less than 8 mm.
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4 Test Apparatus and Procedure
The roof test specimens were tested in the Cyclone Testing Station’s air cannon testing facility. Two
differently sized air cannons were used to fire the timber missile and the steel spheres. Both air cannons
consist of a cylinder, which is pressurised by an air compressor. Once the required air pressure is reached
a solenoid valve is triggered to instantaneously release the air and the missiles are fired through the
barrels and accelerate to the required velocity.
The test specimens were mounted on a target support frame located about 1300 mm away from the
exit opening of the barrels. Digital velocity meters are installed at the exit of the barrels to measure the
velocity of the missiles, at their tail ends, before they impacted the target.
5 Test Specimens
The test roof specimens were set up in a 900 mm triple span arrangement, supported by 1.5 mm BMT
steel z-purlins (Z151015). The cladding was screw fixed to the support at every second corrugation as per
manufacturer’s installation manual using 14-10 x 42 mm self-drilling metal screws fitted with Corri-Lok
cyclone washers.
5.1 Corrugated Cladding
The corrugated steel cladding used in this test program was rolled from G550 steel sheeting with a stated
Base Metal Thickness (BMT) of 0.48 mm. The total sheet width is approximately 860 mm with eleven
sinusoidal corrugations per sheet which are spaced at 76 mm centres. The cover width of the cladding
is 762 mm and the corrugations are approximately 16 mm high. Figure 1 is an end view that shows the
sheeting profile.
Figure 1: End view of Corrugated cladding
6 Results
A summary of the test results is presented in Table 1. Further details on the modes of deformation are
provided in Appendix A.
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Table 1: Impact Testing Results
Impact
Trial Date Impact Location & Velocity
No. Tested Test Load (m/s) Results and Observations
C1 4 Jul 2008 Various (5 impacts), > 34.0 Pass. Small indentations.
Test Load B
C2 12 Mar 2008 Centre of sheet, mid span of 9.1 Pass. Deformation across 3 corrugations.
end span, Test Load A
C3 13 Mar 2008 Centre of sheet, mid span of 17.2 Pass. Deformation across 8 corrugations.
end span, Test Load A
C4 13 Mar 2008 Centre of sheet, mid span of 25.9 Pass. Deformation across entire sheet width.
end span, Test Load A One screw hole on end support elongated.
C5 17 Mar 2008 Side lap, mid span of end 26.2 Pass. Deformation across 7 corrugations.
span, Test Load A Small tear (~50 mm) along internal support.
C6 17 Mar 2008 Centre of sheet, mid span of 26.0 Pass. Deformation across 10 corrugations.
internal span, Test Load A
C7 17 Mar 2008 Centre of sheet, next to end 25.5 Pass. Deformation across 9 corrugations. 4
support in end span, Test screw holes on end support elongated up to
Load A ~30 mm.
C8 17 Mar 2008 Side lap, mid span of 20.9 Pass. Deformation across 7 corrugations.
internal span, Test Load A
C9 17 Mar 2008 Centre of sheet, next to 21.3 Pass. Deformation across 8 corrugations.
internal support in end Crack ~50 mm at corner of missile impact
span, Test Load A location.
7 Conclusions
A test program of simulated wind driven debris impact loading was performed on 0.48 mm BMT
corrugated roof cladding.
The method and criteria of testing (in accordance with the Design Guidelines for Queensland Public
Cyclone Shelters, Sep 2006 including amendment 1) has been presented. The results demonstrate the
performance of the roof cladding when subjected to Debris Test Loads A and B.
The roof cladding tested is deemed to satisfy the vertical trajectory impact load performance
requirements detailed in the Design Guidelines for Queensland Public Cyclone Shelters, Sep 2006.
Prepared by Checked
Mr. U. Frye Mr. C. J. Leitch Prof Y. He
Senior Engineer Manager Head of School
Cyclone Testing Station Cyclone Testing Station School of Engineering and Physical Sciences
James Cook University James Cook University James Cook University
Note: This report may not be:
• Published, except in full, unless permission for publication of an approved abstract has been obtained in writing
from the Head, School of Engineering and Physical Sciences;
• Or cited in any publication or advertising material, unless the proposed citation has been submitted to and
approved in writing by the Head, School of Engineering and Physical Sciences.
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Appendix A – Photographs of Tested Cladding
Figure 2: Cladding damage after Trials C1 (left) and C2 (right)
Figure 3: Cladding damage after Trials C3 (left) and C4 (right)
Figure 4: Cladding damage after Trials C5 (left) and C6 (right)
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Figure 5: Cladding damage after Trials C7 (left) and C8 (right)
Figure 6: Cladding damage after Trial C9
