Small suspension bridges with 7-wire strand cables

The introduction of new codes fundamentally changes the way that small suspension bridges are designed, and will probably change the basic configuration of such bridges. An earlier paper discussed suitable configurations for bridges with prefabricated strands for the main cables. This paper extends the discussion to bridges with main cables made from 7-wire strand systems, similar to those widely used for the stays of cable-stayed bridges. These are likely to be more economic. A design study for a 170m span footbridge is used to show how the configuration of the bridge is driven by the performance characteristics of the simplest 7-wire strand cable system. It is shown that the standard stay system can be used directly, possibly with an increase in wall thickness for the ducts.