Structural-Safety.org

No. 7: Legionnaires’ disease The recent outbreak of Legionnaires' disease in Edinburgh (June 2012) resulted in 44 confirmed cases, including the desaths of three people, with a further 18 requiring hospital treatment (7 of these requiring intensive care). This makes it timely to remind engineers of the hazard and associated risks.

The Awa Shirasagi Ohashi Bridge, which includes novel structural systems, was recently constructed in Tokushima, Japan (Figure 1). There were a number of severe design constraints for the project. The bridge is located in a very environmentally sensitive area. The site is also in a seismic region and is frequently struck by typhoons. Furthermore, the bridge was to be founded on soft alluvium, and to be constructed to a tight budget. These exceptionally challenging constraints led engineers to adopt a novel combination of structural forms, including the ‘cable egret’ cable truss system, an improved form of the permanent tubular steel pile cofferdam foundation and a steel- concrete composite sandwich slab deck.

All articles published in the August 2012 issue.