New Zealand engineers offer quake-resistant bridge design to world

Engineers in New Zealand hope to begin rolling out the world's first earthquake damage-resistant bridge design from later this year in a breakthrough that could help save lives and property by ensuring essential infrastructure survives natural disasters. Dr Alessandro Palermo, of the University of Canterbury, said his research team was very confident in the half-scale prefabricated concrete bridge support since beginning seismic tests in New Zealand's own earthquake battered second city of Christchurch. Current bridge standards coped with protecting life, but they had to accept damage in an earthquake, Palermo told Xinhua in an e- mail interview Monday. However, his research team had developed a self-centering technology that minimized post-quake costs for assessment and repair. The materials were similar to traditional systems, but the design featured high-strength post-tensioning bars or tendons as well as external dissipative fuses, similar to internal reinforcing bars in concrete structures. "Post-tensioning allows the bridge to come back to the original position. It acts as a sort of rubber band while the fuses absorb the energy of the earthquake," said Palermo. The design had no intellectual property protection so it could be taken and developed by any construction company anywhere in the world, he said. "The solution is universal. We are testing a solution which is related to New Zealand practice, but the concept can be applied easily to any other bridge in the world," said Palermo. Palermo had been working with companies to construct a real case study bridge, and in September he would begin working with a New Zealand consulting company to create a working bridge. The Canterbury laboratory was testing a 23-tonne half-scale multi-column bridge support -- 3.5 meters high and 6 meters long -- and loaded with another 40 tonnes to simulate the weight of the bridge deck it would support. It was probably the largest bridge specimen ever tested in a New Zealand laboratory, he said. However, a similar technology had already been tested for single-column bridge piers and had proved very successful. The prefabricated design was cost-effective and allowed a bridge to be built in weeks or days compared with traditional cast- in-place constructions that could take months to years. The design follows a tradition of engineering innovation in New Zealand, where the world's first self-centering bridge, designed by New Zealand scientist Dr Ivan Skinner, was built at Rangitikei in the North Island 40 years ago.