Bridges
Increasingly, around the world, a type of bridge is emerging that is designed principally for cyclists. These bridges, which can be termed velobridges, enhance personal mobility, reduce traffic congestion, improve community health and promote social equity. Given the relatively lighter loads applied to velobridges, they offer opportunities for design innovations and, treated sensitively, they can enhance the urban landscape aesthetic. When designing bridges for the cyclist, special consideration must be given to external clearances, the user envelope, loads and limit state criteria, deflections and dynamic behaviour, access and mobility, security screening, railings, kerbs and balustrades. These issues are explored via several recent bridge developments in Brisbane involving a range of span lengths from 7.5 to 120 metres. Various structural types are covered including girders, orthotropic slabs, trusses, arches and stay cables. Materials discussed include steel, timber, prestressed and reinforced concrete and fibre composites. Velobridges sometimes allow opportunities for access by other active users. This can have capacity implications, which are discussed. The codes referenced during the design of an Australian velobridge are discussed and compared with a variety of other international standards, including the predominant codes of practice adopted in the North America and Europe.