Long span footway bridges: coldformed steel cross-section
Article contains finite element analysis of alternative footway bridge structural construction. There is a possibility to increase building-up speed of construction and decrease congestion on a road due to choice of steel construction technology instead of reinforcement concrete materials used for footbridge. From this point of view we deny so called “wet” works. Architectural and structural design takes into account the following: built-up environment character, its historic and cultural, architectural and town-planning values; conformation; geologic and hydro geological parameters; organization and safety traffic conditions. Space lanning decision takes into account direction of pedestrian traffic and crosswalk pedestrian volume. Structural design ground is based on purpose to implement new and up-to-date technology that implies to use cold formed and thin walled cross-sections. There are many different engineering constructions that are built-up from thin walled cross-sections. Sometimes such a structural model entirely describes construction (for example, bridge span), in other cases — only important bearing elements of structure. Base difference of thin walled from thick-walled cross-section is concluded in behavior laws: breach of Bernoulli (plane-sections) hypothesis. Simple example is I-section deformation, when the last is loaded on end by bimoment. Deviation from Bernoulli (plane-sections) hypothesis is more characterized for open then for closed thin walled crosssections. This is taken into account in non-linear analysis of pedestrian bridge structure. Besides analysis according to 3rd order theory also non-linear material models for metallic materials is considered. The applied elastic-plastic-zone theory is based on the interaction of any internal forces and moments. So, new architectural and structural footway bridge design was modelled and analyzed in the master dissertation. Construction of such a bridge in St.-Petersburg would help not only pedestrian, but also automobilists to get through places with big crosswalk pedestrian volume.