Model updating of a steel box-girder bridge based on field testing: the case study of Niemeyer’s Honestino Guimarães bridge in Brasília, Brazil

This study presents an integrated numerical–experimental assessment of the steel box-girder bridge located in the central span of the Honestino Guimarães Bridge, the only bridge designed and built by Oscar Niemeyer. Motivated by recent rehabilitation works, including the replacement of support bearings, the research combines long- and short-term ambient vibration monitoring, static load testing, and finite element (FE) modelling. Operational Modal Analysis was used to extract modal parameters, which were subsequently employed in a model updating procedure based on a linear programming routine implemented in MATLAB. The updated model achieved frequency discrepancies below 2% and reproduced static strains with errors under 3% when compared with field test results. Beyond the specific case analysed, the study provides a structured and transferable methodological framework for researchers and practitioners working with existing bridges. By demonstrating how ambient vibration data, FE modelling, and iterative updating can be effectively integrated to handle uncertainties in boundary conditions, material properties, and undocumented interventions, this work contributes to ongoing scientific efforts to improve the reliability of numerical simulations and the development of digital twins for ageing infrastructures. The results reinforce findings from recent literature and highlight the value of combining multi-source experimental data with advanced numerical techniques to enhance structural assessment, rehabilitation planning, and long-term monitoring.