Ex-cyclone Oswald damage in Brisbane

This outer Brisbane suburban shopping centre car-park shade structure failed

 during the ex-cyclone passage.  Given the relatively low 125km/hr gust speeds when

compared to the structures intended higher design gust speeds

we suspect a poor connection design has initiated early tube buckling failure.

 Water retention within the roof membrane (failed) was also noted as a potential contributor.

Ex-tropical cyclone Oswald moves through southeast Queensland

Gusts of approximately 125km/hr are quite noticeable in Brisbane (as predicted by the passing of ex-cyclone Osward ) but are well below the design cyclonic wind speeds that our houses are designed to withstand.  In a residential area of a typical Brisbane suburb set in flat surrounding terrain the Australian design standards would allow gust wind speeds to peek up to 144km/hr.  Exposed house sites on ridge lines or adjacent to open parks may be designed for gusts of 180km/hr.

Large exposed structures in a public places should also be designed to withstand significantly high wind speeds.  The early beam buckling failure of the shade structured pictured above suggests that its performance has been adversely reduced by a poor connection design detail.

The well known fact that most structural failures originate from poor connection design appears to be proven yet again in this instance.  From my experience connection design was given very little treatment in undergraduate course structural subjects.  There is something quite wrong about this lack of specific course treatment.

Super-storm Sandy proves fatal for some on the US East coast

A large tree in Methuen, Mass. Tuesday, Oct. 30, 2012 lays atop power lines due to Monday's hybrid superstorm Sandy. Sandy caused multiple fatalities, halted mass transit and cut power to more than 6 million homes and businesses. (AP Photo/Elise Amendola)

Written by

Allen G. Breed and Tom Hays

Associated Press

"NEW YORK — Millions of people from Maine to the Carolinas awoke Tuesday without electricity, and an eerily quiet New York City was all but closed off by car, train and air as superstorm Sandy steamed inland, still delivering punishing wind and rain. The U.S. death toll climbed to 39, many of the victims killed by falling trees.
The most devastating storm in decades to hit the country’s most densely populated region upended man and nature as it rolled back the clock on 21st-century lives, cutting off modern communication and leaving millions without power Tuesday as thousands who fled their water-menaced homes wondered when — if — life would return to normal."

http://www.pnj.com/viewart/20121031/HURRICANE/310310034/Superstorm-Sandy-makes-landfall?odyssey=tab|topnews|img|FRONTPAGE

In earlier days rural development would see the house paddocks cleared of trees to make way for the family farm home to be built.  Today in urban areas, trees offer a beautiful asset and increase the value and attractiveness of your street-cape and neighborhood.