The team’s observations show that most contemporary housing has not sustained much structural wind damage, demonstrating that where the building Codes and Standards have been rigidly followed housing has performed well.
Unfortunately some older houses and some houses exposed to storm surge suffered extensive damage.
The CTS team leader in the field, Dr Geoff Boughton, said that the analysis of damage to simple structures throughout the region indicated that the wind speeds on the ground in Tropical Cyclone Yasi were less than those expected in a Category 5 event.
Using techniques developed and refined in previous cyclones, the CTS team has formed a preliminary view that the maximum wind speed in Cyclone Yasi was about the same as that in Tropical Cyclone Larry.
"We estimate that the gust wind speeds in some of the most affected areas were about 220 km/h" Dr Boughton said.
"As the wind speed does not appear to have been greater than the design wind speed of buildings in the region, we would expect that any modern houses should have performed well under Yasi’s wind loads.
"Our observations show that throughout the region, most contemporary housing has not sustained much structural wind damage. It has demonstrated that where builders have diligently applied the Codes and Standards, housing has performed well."
One item of concern is the general poor performance of roller doors.
"During Cyclone Larry many roller doors in both houses and sheds failed at loads less than the design load and we have observed the same after Yasi," Dr Boughton said.
The Cyclone Testing Station has previously published an Information Bulletin expressing concerns about roller door performance, which is available on the CTS web site at www.jcu.edu.au/cts.
Other issues identified in the Cyclone Yasi investigation include damage to tiled roofs, guttering and flashings, and the CTS report will include recommendations on these.
"These issues need to be addressed, but overall we have been pleased with the performance of contemporary buildings in the high winds associated with Yasi," Dr Boughton said.
"The CTS team is grateful for the assistance and cooperation of the people of the Cassowary Coast during the study," he said.