Multi-million dollar repairs needed to prevent Perth Convention and Exhibition Centre sinking

Just 15 years after its opening, the Perth Convention and Exhibition Centre is facing the prospect of major expenditure to reinforce its structural integrity as its foundations are slowly slipping into the Swan River.

Opened in 2004, Perth's largest exhibition space attracts more than 800,000 visitors each year. However, it faces a multi-million dollar bill to remedy its structural problems which are most obvious in undulating ‘speed bumps’ that have developed in a car park at the base of the venue creating hazards for cars and people.

The sinkage affects around 30% of the car park and is in some places 40cm deep.

Expected to cost more than $10 million, City of Perth has allocated $4 million to fix the problem in its 2019/20 budget

The $310 million structure was built on Western Australian Government land by the Multiplex Consortium - which included Multiplex Constructions Pty Ltd and Accor Asia Pacific Pty Ltd.

It is privately operated under a 35-year lease from the Western Australian Government while the car park is operated by the City of Perth.

City of Perth Head of Infrastructure and Operations, Chris Kopec, said a permanent solution for the subsidence problem could take at least three years and cost "more than $10 million" to fix.

Kopec told ABC Radio Perth "the bedrock is about 28 metres deep, it's about on average probably 25, obviously there's a significant amount of soil there, and how it reacts in different areas of the carpark is different.

"There's a permanent solution which involves piling to bedrock, much in the way the building is supported down on bedrock, then re-laying a carpark over those piles, to effectively mean it's independent of the ground that its subsiding below."

Kopec said there had been 10 reports to the council of damage to vehicles or people tripping over the bumps since January.

Kopec, who was not involved with the original build, said ongoing short-term work was being done to address the issue while a long-term solution was decided.

He added “it's not something you see very often, but as I said it's a complicated scenario beneath there.

"I don't know what decisions were made back in the construction timeframe with regards to the method of construction."

A spokesman for the City of Perth said as the carpark was a Western Australian Government-appointed contract, it was not for the city to disclose any historical contractual or legal recourse details.