Conceptual design and parametric analysis of curvilinear cable-stayed footbridges

Curvilinear cable-stay bridges represent an alternative to conventional footbridges in city areas where there is not much space available. They can also harmonize better with the urban context, being more pleasing to the eye and integrating better pedestrian ramps, inviting users to walk on them. This presents an additional challenge to engineers, since out-of-plane effects need to be taken into consideration when analyzing the deck, the cable system and the mast. In recent years, engineers have developed innovative systems considering a curved deck supported by one cable plane and additional elements to counteract the torsional effects. This thesis presents a conceptual design and a parametric analysis of two typologies of this type of bridge. A literature review is presented where several cases are described, and the two main typologies are identified according to the relative position of the mast within the curve. An equilibrium of torsional moments is presented for each typology, identifying how the bridges can counteract the torsion induced by the external loads. The analysis allows the identification of several parameters that affect the equilibrium of the bridge. Using a parametric design software, relationships are obtained between the curvature and the geometric configuration of the cable system and their effect on the deck. The mast was also included in the analysis, since is the other main component of the bridge. Some of the relationships obtained are not linear, which highlights the importance of the parametric analysis for this type of structure.