Engineers rule out Opal Tower concrete issues

Engineers investigating the cause of cracking at Opal Tower say it is not due to an inherent fault in the prefabricated concrete panel.

The 38-storey Opal Tower building at Olympic Park. Picture: Tim Pascoe

Structural engineers have ruled out any inherent fault in a prefabricated concrete panel as the cause of cracking in a residential high-rise in Sydney’s west, meaning the damage is the result of how it was installed or problems in the design or construction of the building.

The assessment, which has not been made public but can be revealed by The Australian, marks a significant step in determining who might bear responsibility for the continuing crisis that erupted at the 38-storey Opal Tower at Olympic Park.

About 300 residents remain in hotels and other accommodation since they were moved out late last week at the request of the developer, Ecove, and the builder, Icon, to allow investigators to assess and correct what led to the 10th-floor crack on Christmas Eve.

The state government yesterday said it would stick with the much-criticised practice of allowing private-sector certifiers paid by developers or builders to declare that buildings have followed planning and construction codes, rather than reintroduce the previous system in which certifiers were employed by local or state government.

But Better Regulation Minister Matt Kean announced a tightening of the policing of private certifiers, saying that if developers were “working with their certifier mates to push shabby buildings through then we will rub them out of the ­industry”.

There are now four separate sets of investigators, including two university deans of engineering engaged by the state government, combing over Opal Tower, looking to find what caused the crack in the precast concrete panel measuring 6m by 3m and 30cm thick.

The panel was manufactured by Evolution Precast Systems, a company also in western Sydney, and it is understood about 230 of them were installed at Opal Tower to make up the walls around 12 garden “slots” in the building.

Structural engineers last week closely examined the panels to determine if flaws in their manufacture before arriving at the site might have caused the cracking.

But a source close to one of the investigations told The Australian “it’s not the precast panels”.

“It does seem to be not the ­material itself,” the source said.

Structural engineer Ali ­Hadigheh from the University of Sydney has said such cracking was not often associated with the manufacture of a precast panel itself but more often how it was attached to the columns, or difficulties in the structure of the building itself.

The Liberal-National state government has been under pressure for fast-tracking Opal Tower by declaring it a state significant development free from council planning oversight, and for allowing the rate of construction of high-rise apartment blocks to nearly quadruple over the past decade.

“Make no mistake — the problems in the certification industry were created by Labor with the botched privatisation leaving the industry open to cowboys and shonks who have cast a shadow on the entire profession,” Mr Kean said.

Asked if the government would bring certifiers back under the ­employ of government, Mr Kean said that was not the issue.