in Vol. 14 - September Issue - Year 2013
Stress Measurements On The "Bizkaia Bridge" In Bilbao, Spain
View of the horizontal bars
Measuring equipment measures stresses on the horizontal bars
Measurement of stresses on the upper girder
View of Bizkaia Bridge, Bilbao, Spain. The hanging gondola transports personal cars and persons over the Nervion River
120 years is quite an old age for a structure built completely by steel. In 2011, the Bizkaia Bridge staff appointed Prof. Santiago Sánchez-Beitia at the Basque Country University (E.T.S. de Arquitectura of Donostia-San Sebastián) to perform stress measurements on some critical points of the bridge. "Our Xstress 3000 G2R is the ideal tool for doing this job", says Prof. Sánchez-Beitia, who has used it since 2010 and is regularly travelling with the equipment mainly throughout Spain and Portugal.
The Bizkaia Bridge is the oldest hanging bridge in the world, which is still in daily use. It is used for transporting cars and persons over the Nervion River in Bilbao. It was built in 1893, designed by Alberto Palacio, one of Gustave Eiffel’s disciples. In July 2006, it was declared a World Heritage Site by the UNESCO.
The task was to measure the stresses on the steel cables, which fix the two towers to the ground, and on the horizontal bars at a 55 m height! There was a special interest in knowing the resulting stresses during the movement of the gondola. As you can see in the photo, the strong magnets of the Xstress 3000 G2R give confidence even in cases of extreme measurement locations!
Less dangerous, but not less important were the measurements of the stresses in the steel cables near the point of connection to the ground: "We found that there is a clear influence of the movement of the gondola on the measured stresses", says Prof. Sánchez-Beitia, "however, you can use the Bizkaia Bridge without any worry, the next time you are in Bilbao!"