Engineers grapple with nature’s fury

Roads are on the research agenda for a southern Queensland university, as heavy rain is forecast to drench the region once again. Rainfall events in Queensland over the past three years have exceeded what would be expected for a one-in-100-year average, says Dr Helen Fairweather, senior lecturer and research fellow in environmental engineering at the University of the Sunshine Coast. Fairweather said the climate change projections released by the Intergovernmental Panel on Climate Change suggest that we can expect more intense rainfall events than in the past. “On the Sunshine Coast over the last few years we have certainly experienced our fair share of heavy downpours,” she said. Fairweather is investigating whether the present local storms have exceeded the expected rainfall intensity, which is a 4 per cent increase in intensity for every degree of global warming. Her colleague at USC, professor of construction engineering John Yeaman, is excited about the research possibilities for his university and the Sunshine Coast which relates to his expertise – road pavements. Yeaman is also the former long-time owner of Sydney-based consultancy Pavement Management Services which operated as far afield as Abu Dhabi. “Australian pavements are designed for 20 years although many experience a shorter life cycle,” he said. When water gets into the pavement, it reduces the stiffness of the structure and the bending and flexing of the pavement under load will cause the water proof surface to fatigue, leading to the formation of potholes. Yeaman said heavy rainfall is responsible for the destruction of pavements in Queensland each year and cost the state government millions of dollars to repair. “The cost of repairs increases rapidly from preventative maintenance to corrective maintenance and to renewal in the ratio $1 to $15 to $55,” Yeaman said. He said the current life cycle of the pavements puts the estimated asset value at about $130 billion and a renewal cost at $3.2 billion per year. “If we can increase the nominal life by just one year, by 5 per cent, that cost could be reduced to $3 billion, or a saving of $200 million.” “With quality research, we might be able to do even better than that,” Yeaman said.