Integrative approaches to footbridge design in natural river environments. Two example cases in GaIcia, Spain

The design of footbridges in natural river environments implies some specific factors that are critical in their conception. River environments are very sensitive ecosystems, susceptible to impacts generated during construction stages. The temporary risings of the water level during floods usually determines a very high elevation of the footbridge deck from the ground, which combined with the accessibility requirements for the access ramps, produces a strong visual relevance that is not always desirable in natural environments. The location and size of the access ramps affect the river flow dynamics that must be avoided.

Two different footbridges are presented in this paper, located in natural river environments and designed to address these issues. They show several common elements: both are cable-stayed solutions, with composite steel-concrete deck section using weathering steel. These solutions aim for a lower visual impact and a better integration into the environment, as well as diminishing the environmental impacts during construction, because smaller machinery is needed due to the light weight of the structural elements. Additionally, the cable-stayed solution allows greater flexibility to design a geometry that better integrates with the surroundings.