First published 27 March 2020

Masonry usually refers to bricks of clay, blocks of concrete, natural stone and similar products laid in mortar, but also refers to the bricklaying trade.

Workforce decline and lingering perceptions of product performance in catastrophic events continue to haunt the industry, says QUT structural engineering researcher Dr Hossein Derakhshan.

“Masonry is a superior construction material in terms of fire resistance and durability but its weaknesses cannot be ignored.

“Historically, it has low resistance to tensile forces caused by earthquakes, wind, impact or other vibrations applied to structures.

“Although design provisions were revised in building codes for robustness of masonry following Tropical Cyclone Tracy, and the 1989 Newcastle Earthquake, people still think it may be unsafe in hazardous events.

Dr Derakhshan said Australia’s earthquakes had a lasting impact on the industry.

“Masonry became unpopular in Queensland for decades following a 1918 earthquake.

“Adelaide suffered damage that would cost about $600M in today’s value after an earthquake in 1954.

“In Meckering 1968, a small village was severely destructed and had to be re-built in another location.

“Newcastle had a major disrupting earthquake in 1989 that caused 13 deaths and almost $4B in damages in today’s dollars.

“Policy-makers need evidence before promoting masonry considering its historical performance.

“The industry needs new engineering solutions if it wants to survive,” Dr Derakhshan said.

Masonry specimen tested for tensile strength.
Masonry specimen tested for tensile strength. Image provided by Dr Hossein Derakhshan.

Research to improve masonry performance is underway

QUT is assessing the seismic risks and effect of mitigation strategies on masonry performance through its Banyo Pilot Plant - a general-purpose facility for large-scale or scaled-up engineering and science research.

Here, it is also investigating the behaviour of different types of masonry including drystack (mortarless masonry) and reinforced masonry under various loads.

However, industry could take greater focus on proof-testing contemporary building prototypes against realistic loads, according to Dr Tatheer Zahra who is also a structural engineering researcher with QUT.

“A lot of research to date has focused on smaller parts of buildings, and been done independently in Australian academic institutions.

“If complete buildings were proof-tested, more accurate research data is obtained and result in more significant impact.

“This type of research has been done in other countries with low seismicity, most recently in the Netherlands where buildings are subjected to small earthquakes linked to gas extraction,” Dr Zahra said.

Construction contributes $134.2B (8.1%) of Australia’s GDP annually. An estimated 60% of Australian building stock made of masonry material.

Rising interstate and international migration have triggered new dwelling construction – up 18% nationally in 2019 - but the number of skilled masons has dropped due to fewer apprentice starts and an ageing workforce, creating a major skills gap.

Higher labour intensity and wages compared with other construction trades due to a shortage of bricklayers has also given industry the perception that masonry is expensive.

QUT hosted major industry members and researchers from all states and territories at the inaugural Masonry Resilience Forum last year to discuss future-proofing strategies.

Participants identified the need to redefine masonry within the Australian Masonry Standards (AS3700) to include other masonry types such as mortarless masonry; to innovate through prefabricated construction, and use of bricklaying robots to reduce dependency on skilled labour.

Despite its drawbacks, alternatives to masonry including wood, steel and concrete also had weaknesses, according to Dr Derakhshan.

“Other materials such as steel and concrete are expensive by comparison.

“Steel requires more technology to use and concrete, including its Portland cement ingredient, is a major contributor to environmental pollution. Both require more energy to manufacture than masonry.

“A few wooden products may be comparable in price but not in fire resistance and insulation,” Dr Derakhshan said.

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