Water tank collapse at Sunshine Coast University Hospital, Kawana Way. The scene was described by witnesses as being like a tsunami.  Photo: Che Chapman / Sunshine Coast Daily
Water tank collapse at Sunshine Coast University Hospital, Kawana Way. The scene was described by witnesses as being like a tsunami. Photo: Che Chapman / Sunshine Coast Daily Che Chapman

'Time bomb' tank failed due to bolts, professor claims

AN ENGINEERING consultant who was contracted to determine why a water tank collapsed at the Sunshine Coast University Hospital told a hearing the structure was a "time bomb" and it was a matter of when, not if, it failed.

Professor Peter Dux gave his testimony in Maroochydore Magistrates Court during the third day of the hearing against Lindsay Consulting and its owner, engineer Jason Lindsay, who designed the Thermal Energy Storage tank.

Mr Lindsay pleaded not guilty to failure to comply with a health and safety duty that exposes a person to risk of death, serious injury or illness over the October 2015 incident which caused 2.7 million litres of water to engulf Kawana Way.

 

ACCUSED: Jason Lindsay's company designed the water tank that collapsed on Kawana Way.
ACCUSED: Jason Lindsay's company designed the water tank that collapsed on Kawana Way. Sarah Barnham

Currimundi mother-of-two Lou O'Brien and her twins Zali and Alex suffered the brunt of the water's force, but managed to escape their car with minor injuries before it was washed away.

The fault occurred just 400 days before the hospital was due to open and developer Lendlease replaced the tanks with assurances they were safe by May.

Prof Dux was approached by Workplace Health and Safety Queensland to examine the cause of the TES tank fault which he preliminarily determined to be due to the overloading of bolts.

Mr Lindsay was responsible for the design of the tank, but its fabrication was carried out by Australasia Liquid Storage.

He was not involved in the construction process, was not notified the tank had been built and was never asked to inspect it.

During cross-examination it was revealed ALS had changed the design it was given by Mr Lindsay, but Prof Dux said even if the certified design had been used it "would be hanging on by its teeth".

When pressed Prof Dux conceded his report on the failure had been based off the changed design and not Mr Lindsay's, but said it didn't matter as the issues with the bolts were the same.

Prof Dux said the tank was comprised of 19 horizontal bands of steel, called strakes, which were made up of 14 plates ranging from 3-16mm in thickness from the top of the tank to the bottom as the pressure increased.

The 12mm bolts used vertically ranged from 30-60mm in length from the top down.

Where the tank failed, Prof Dux said bolts that were supposed to be 50mm in length, according to the design, but were actually 40mm.

He said through investigations it was determined the tank would fault when water reached about 21m and if the tank had held together, it would have been a "time bomb" at risk of failing.

Prof Dux said a "design failure", rather than construction issues were to blame for the fault which could have been alleviated with thicker bolts as the ones used "weren't adequate".

Although Mr Lindsay made no recommendations on the bolt size to be used, Prof Dux said his design featured 14mm holes which were used for 12mm bolts.

The testing process Prof Dux undertook to determine the cause of fault was questioned as he used bolts which were from the same supplier, but a different batch.

There were also questions raised about the type of ssteel Prof Dux used to conduct the experiment, but he maintained it was the same as that used for the tank.

The hearing is expected to continue today.