A 33.5m-long four-span concrete bridge built by the University of Nevada in Reno, USA, has survived a series of nine increasingly powerful 'earthquakes' in the large-structures laboratory. The final test carried out this week involved simulating a magnitude 8.0 earthquake.
'This is very satisfying to see how well the design and components worked,' said the principal investigator for the project and University of Nevada civil engineering professor Saiid Saiidi. 'We estimated bridge failure at eight inches (203mm) of deflection, which is a lot, but we had 10 inches (254mm) of deflection in the support columns and the bridge remained standing and usable, even with considerable internal stresses.'
The 200t model bridge was shaken with bi-directional forces for realistic simulation. Tests used recorded data to mimic the magnitude 6.9 Northridge earthquake.
The University of Nevada research team is experimenting with and testing a number of materials and innovations for input into seismic design of future bridges. Features include the use of glass and carbon fibres to support the bridge, precast columns, segmental columns and special steel pipe-pin connections.
