Non-Deterministic Dynamic Structural Analysis of the Honestino Guimarães Bridge Steel Central Span (Brasília/DF)

Resumo

The Honestino Guimarães bridge was inaugurated in the mid-1970s and is the only structure of its kind in Brasília/DF, Brazil, designed by the renowned architect Oscar Niemeyer, where his understanding of structural systems was used aiming to create a symbolic and harmonious environment, having in mind a structural system composed by steel and concrete. The central span of the bridge is made of steel, with an orthotropic deck, presenting an arched shape, Gerber joint connection, and longitudinal symmetry. This way, this research work aims to investigate the non-deterministic dynamic structural behaviour and assess the structural fatigue on the central span of the bridge. A global finite element model and a numerical submodel were developed using the ANSYS software, incorporating the main physical and mechanical characteristics of the bridge’s central span, which measures 58 m in length and 13.50 m in width, with the concrete slab thickness varying from 0.07 m to 0.12 m. Thus, the hot-spot stresses were determined from the submodel created from shell elements (SHELL188), and identified through the use of the Vehicle Bridge Interaction (VBI) computational software, which integrates the ANSYS and MATLAB software. It was observed that, as the vehicle velocity increases, the time interval in which hot-spot stresses reach the maximum values decreases. The interval between maximum stresses shortens as the vehicle velocity increases, indicating faster and more concentrated dynamic loads. The intensity of hot-spot stresses is more influenced by the number of vibration modes than by the vehicle velocity, highlighting the importance of appropriate numerical modelling in order to capture the dynamic effects.